US009853326B2 (12 ) United States Patent ( 10) Patent No. : US 9 ,853 , 326 B2 Tokuda et al. ( 45 ) Date of Patent: Dec. 26 , 2017

( 54 ) NONAQUEOUS ELECTROLYTE FOR (58 ) Field of Classification Search SECONDARY BATTERY AND CPC ...... HO1M 10 /0569 ; HOTM 10 /0567 ; HOLM NONAQUEOUS - ELECTROLYTE 10 /0525 ; HOTM 4 /587 ; HOTM 4 / 134 ; SECONDARY BATTERY EMPLOYING THE HO1M 2300 /0025 ; YO2E 60 / 122 SAME See application file for complete search history . References Cited ( 71 ) Applicant: MITSUBISHI CHEMICAL (56 ) CORPORATION , Chiyoda- ku ( JP ) U .S . PATENT DOCUMENTS 5 ,580 ,684 A 12 / 1996 Yokoyama et al . (72 ) Inventors : Hiroyuki Tokuda, Ibaraki ( JP ); 5 , 754 , 393 A 5 / 1998 Hiratsuka et al. Minoru Kotato , Ibaraki ( JP ); Masahiro 6 ,001 , 325 A 12 / 1999 Salmon et al. Takehara , Ibaraki ( JP ) ; Shinichi 6 ,033 , 808 A 3 / 2000 Salmon et al. Kinoshita , Ibaraki ( JP ) 6 ,436 , 582 B1 8 / 2002 Hamamoto et al. 6 , 919, 145 B1 7 / 2005 Kotato et al . 2001/ 0044051 AL 11/ 2001 Hamamoto et al. ( 73 ) Assignee: MITSUBISHI CHEMICAL 2002 / 0192564 Al 12 /2002 Ota et al. CORPORATION , Chiyoda -ku ( JP ) 2004 / 0048164 Al 3 /2004 Jung et al. 2004 / 0091786 A1 5 / 2004 Unoki et al. 2004 / 0191636 A1 9 / 2004 Kida et al . ( * ) Notice: Subject to any disclaimer, the term of this 2005 / 0008939 A1 1 / 2005 Ota et al. patent is extended or adjusted under 35 2005 /0014071 A1 1 / 2005 Noda et al. U . S . C . 154 ( b ) by 412 days. 2005 / 0084765 A1 4 / 2005 Lee et al . 2005 /0118512 Al 6 / 2005 Onuki et al . 2005 /0191553 A1 9 /2005 Fujihara et al. ( 21) Appl. No .: 13/ 846 , 254 2006 /0088763 A14 / 2006 Li et al . ( 22 ) Filed : Mar . 18 , 2013 (Continued ) (65 ) Prior Publication Data FOREIGN PATENT DOCUMENTS CN 1437777 A 8 / 2003 US 2013/ 0216918 A1 Aug . 22 , 2013 CN 1181592 C 12 / 2004 (Continued ) Related U . S . Application Data (62 ) Division of application No . 13/ 619 ,147 , filed on Sep . OTHER PUBLICATIONS 14 , 2012 , now Pat. No . 9 ,093 ,716 , which is a division Combined Office Action and Search Report dated Jan . 20 , 2014 in of application No . 12 /594 ,513 , filed as application Chinese Application No . 201210059236 . 3 ( With English Transla No. PCT/ JP2008 /056803 on Apr. 4 , 2008 , now Pat. tion and English Translation of Category of Cited Documents) . No. 9 , 281, 541 . Chinese Office Action dated Jan . 28, 2015 in Patent Application No . 200880011461 . 1 (with English Translation ) . Foreign Application Priority Data Communication pursuant to Article 94 ( 3 ) EPC dated Aug . 29 , 2014 (30 ) in European Patent Application No . 11 188 812 . 9 . Apr. 5 , 2007 ( JP ) Office Action dated Apr. 6 , 2015 in Korean patent Application No ...... 2007 - 099274 10 - 2009 - 7020547 (with English translation ) . Apr. 20 , 2007 ( JP ) ...... 2007 - 111931 U . S . Appl. No. 14 /624 ,914 , filed Feb . 18 , 2015 , Fujii, et al . Apr. 20 , 2007 ( JP ) . . 2007 - 111961 U . S . Appl. No. 14 /644 , 905 , filed Mar . 11, 2015 , Fujii , et al . Apr. 26 , 2007 ( JP ) ...... 2007 - 116442 Korean Office Action dated Feb . 4 , 2015 in Patent Application No. Apr. 26 , 2007 (JP ) ...... 2007 - 116445 10 - 2014 -7036628 ( with English Translation ) . Apr. 26 , 2007 ( JP ) ...... 2007 - 116450 (Continued ) ( 51 ) Int . Ci. Primary Examiner — Laura Weiner HOIM 10 /0567 ( 2010 . 01) (74 ) Attorney , Agent, or Firm — Oblon , McClelland , HOIM 4 / 133 ( 2010 .01 ) Maier & Neustadt, L . L . P . HOIM 4 / 134 ( 2010 .01 ) HOIM 4 /587 ( 2010 .01 ) (57 ) ABSTRACT HOIM 10 /0525 ( 2010 .01 ) An object is to provide a nonaqueous electrolyte and a HOIM 10 / 0569 ( 2010 .01 ) nonaqueous - electrolyte secondary battery which have excel HOIM 10 /052 ( 2010 .01 ) lent discharge load characteristics and are excellent in high HOIM 10 /056 (2010 . 01) temperature storability, cycle characteristics , high capacity , (52 ) U .S . CI. continuous - charge characteristics , storability, gas evolution CPC ...... HOIM 10 /0567 (2013 .01 ) ; HOIM 4 / 133 inhibition during continuous charge , high -current - density ( 2013 .01 ) ; HOTM 4 / 134 ( 2013. 01 ) ; HOIM charge / discharge characteristics , discharge load characteris 4 / 587 ( 2013 . 01 ) ; HOIM 10 /052 ( 2013 .01 ) ; tics , etc. The object has been accomplished with a nonaque HOIM 10 / 056 ( 2013 . 01 ) ; HOIM 10 /0525 ous electrolyte which comprises: a monofluorophosphate ( 2013 .01 ) ; HOIM 10 /0569 ( 2013 . 01 ) ; HOIM and / or a difluorophosphate ; and further a compound having 2300 /004 (2013 . 01 ) ; HOIM 2300 / 0025 a specific chemical structure or specific properties . ( 2013. 01 ) ; YO2E 60 /122 ( 2013 .01 ) 5 Claims, No Drawings US 9 ,853 , 326 B2 Page 2

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Office Action dated Jun . 9 , 2016 in Korean Patent Application No . 10 - 2015 - 7019150 ( with English language translation ). * cited by examiner US 9 ,853 , 326 B2 NONAQUEOUS ELECTROLYTE FOR degree , a coating film having high resistance is formed on SECONDARY BATTERY AND the negative - electrode side and this , in particular, reduces NONAQUEOUS - ELECTROLYTE discharge load characteristics . SECONDARY BATTERY EMPLOYING THE Nonaqueous Electrolyte 2 and SAME Nonaqueous- Electrolyte Secondary Battery 2 CROSS REFERENCE TO RELATED APPLICATIONS Secondary, various investigations have been made on nonaqueous solvents and electrolytes for use in those non The present application is a divisional of U .S . patent 10 aqueous electrolytes in order to improve the battery char application Ser . No . 13 /619 ,147 , now U . S . Pat. No . 9 ,093 , acteristics including load characteristics , cycle characteris 716 , filed on Sep . 14 , 2012 , which is a divisional of patent tics, and storability of those lithium secondary batteries . For application Ser. No. 12/ 594 ,513 , filed on Jan. 6 , 2010, now example , use of a nonaqueous solvent having a higher U . S . Pat. No . 9 , 281 , 541, which is a 35 U . S . C . $ 371 national permittivity and a lower coefficient of viscosity has various stage patent application of international patent application 15 advantages, e . g . , the resistance of the electrolyte can be PCT /JP2008 / 056803 , filed Apr. 4 , 2008 , which claims pri reduced to a low value , as described in non - patent document ority to the following Japanese patent applications: JP 1 . Furthermore , that nonaqueous solvent is thought to be 2007 -099274 , filed Apr . 5 , 2007 ; JP 2007 - 111931 , filed Apr. capable of improving infiltration into the positive and nega 20 , 2007 ; JP 2007 - 111961, filed Apr. 20 , 2007 ; JP 2007 tive electrodes . Use of that nonaqueous solvent is hence 116442 , filed Apr. 26 , 2007 ; JP 2007 - 116445 , filed Apr. 26 , 20 preferred . 2007 ; and JP 2007 - 116450 , filed Apr . 26 , 2007 . However, solvents having a heteroelement -containing functional group (group constituting a framework ) other TECHNICAL FIELD than a carbonyl framework , such as ether compounds and nitrile compounds, which are one kind of preferred solvents The present invention relates to a nonaqueous electrolyte 25 from those standpoints have the following drawback . These for secondary battery and to secondary battery employing solvents are electrochemically decomposed by an oxidation the electrolyte. More particularly , the invention relates to reaction at the positive electrode or by a reduction reaction nonaqueous electrolyte which is for use in lithium secondary at the negative electrode and are hence difficult to use . battery and contain a specific ingredient, and to lithium Practically , carbonic esters or carboxylic acid esters, such as secondary battery employing the electrolyte . 30 enumerated above as examples , are used in combination . These solvents have a carbonyl group and have excellent BACKGROUND ART oxidation resistance/ reduction resistance . On the other hand , patent document 1 includes a statement Nonaqueous Electrolyte 1 and to the effect that when an electrolyte containing a vinyleth Nonaqueous - Electrolyte Secondary Battery 1 35 ylene carbonate compound is used , the decomposition of this electrolyte is minimized and a battery excellent in With the recent trend toward size reduction in electronic storability and cycle characteristics can be fabricated . Patent appliances , secondary batteries are increasingly required to document 2 includes a statement to the effect that when an have a higher capacity . Attention is hence focused on lithium electrolyte containing propanesultone is used , recovery secondary batteries (nonaqueous - electrolyte secondary bat - 40 capacity after storage can be increased . teries ) , which have a higher energy density than nickel- However, incorporation of such compounds has had the cadmium batteries and nickel- hydrogen batteries. following problem although the incorporation has the effect The electrolytes used in lithium secondary batteries are of improving storability and cycle characteristics to some nonaqueous electrolytes prepared by dissolving an electro - degree . When these compounds are used in order to suffi lyte such as LiPF . , LiBF4, LiC104, LiCF3SO3, LiAsF6 , 45 ciently improve characteristics, a coating film having high LiN (CF SO , ) , or LiCF (CF , ) 2SO , in a nonaqueous solvent resistance is formed on the negative -electrode side and this , such as a cyclic carbonate , e . g ., ethylene carbonate or in particular, reduces discharge load characteristics. Espe propylene carbonate , an acyclic carbonate , e. g . , dimethyl cially when those solvents which have a heteroelement carbonate , diethyl carbonate , or ethyl methyl carbonate , a containing functional group ( group constituting a frame cyclic ester , e .g ., y- butyrolactone or y- valerolactone, an 50 work ) other than a carbonyl framework and have a high acyclic ester , e . g . , methyl acetate or methyl propionate , or permittivity and a low viscosity are used , there has been a the like. problem that the preferred characteristics are not imparted . First , various investigations have been made on nonaque The desire for higher performances in nonaqueous - elec ous solvents and electrolytes in order to improve the battery trolyte secondary batteries is growing more and more , and it characteristics including load characteristics , cycle charac - 55 is desired to attain various characteristics including high teristics, and storability of such lithium secondary batteries . capacity , high -temperature storability , continuous - charge For example, patent document 1 includes a statement to the characteristics , and cycle characteristics on a high level. effect that when an electrolyte containing a vinylethylene carbonate compound is used , the decomposition of this Nonaqueous Electrolyte 3 and electrolyte is minimized and a battery excellent in storability 60 Nonaqueous - Electrolyte Secondary Battery 3 and cycle characteristics can be fabricated . Patent document 2 includes a statement to the effect that when an electrolyte Thirdly , various investigations have been made on non containing propanesultone is used , recovery capacity after aqueous solvents and electrolytes in order to improve the storage can be increased . battery characteristics including load characteristics , cycle However, incorporation of such compounds has had a 65 characteristics, and storability of such lithium secondary problem that although the incorporation has the effect of batteries . For example , patent document 3 includes a state improving storability and cycle characteristics to some ment to the effect that when an electrolyte containing a US 9 ,853 , 326 B2 phosphinic acid ester is used , a battery inhibited from based negative electrode and an improved initial charge! deteriorating in battery performance during high - tempera discharge efficiency is obtained . ture storage or during continuous discharge can be fabri cated . Patent document 4 proposes a secondary battery Nonaqueous Electrolyte 5 and which has an excellent life in charge/ discharge cycling at a 5 Nonaqueous- Electrolyte Secondary Battery 5 voltage exceeding 4 . 2V and is fabricated using an electrolyte containing an organic compound having two or more cyano Fifthly , many reports have been made on the addition of groups . various additives to electrolytes for the purpose of improv Especially when a battery is in the state of being continu ing initial capacity , rate characteristics, cycle characteristics, ously charged in which a slight current is permitted to 10 high - temperature storability , low -temperature characteris always flow therethrough to keep the battery in a charged tics, continuous -charge characteristics, self -discharge char state in order to compensate for the self -discharge of the acteristics , overcharge - preventive properties, etc . For battery , then the electrodes are always in the state of having example , to add 1 , 4 , 8 , 11 - tetraazacyclotetradecane has been reported as a technique for improving cycle characteristics high activity . Because of this, the battery is apt to suffer 15 (see patent document 7 ) . accelerated deterioration in capacity or gas evolution is apt However, the desire for higher performances in nonaque to occur due to the decomposition of the electrolyte . In ous -electrolyte secondary batteries is growing more and particular, in the case of a battery having high capacity , there more , and it is desired to attain various characteristics is a problem that since the space within this battery has a including high capacity , high -temperature storability, con small volume, the internal pressure of the battery increases 20 tinuous- charge characteristics and cycle characteristics on a considerably even when a slight amount of a gas is evolved high level. For example , the prior- art technique disclosed in due to the decomposition of the electrolyte . With respect to patent document 7 , which is regarded therein as effective in continuous -charge characteristics , not only reduced capacity improving cycle characteristics , has had a problem that this deterioration but also the inhibition of gas evolution are technique , when used alone, results in considerable gas strongly desired. 25 evolution during continuous charge and in a considerable However , the electrolytes containing the compounds decrease in recovery capacity after a test, as will be shown described in patent document 3 and patent document 4 have later in a Reference Example . been insufficient in the inhibition of gas evolution during continuous charge and in the inhibition of battery charac Nonaqueous Electrolyte 6 and teristics deterioration , although the electrolytes have the 30 Nonaqueous- Electrolyte Secondary Battery 6 effect of improving cycle characteristics and storability to Sixthly , various investigations have been made on non some degree . aqueous solvents and electrolytes in order to improve the Nonaqueous Electrolyte 4 and battery characteristics including load characteristics, cycle Nonaqueous- Electrolyte Secondary Battery 4 35 characteristics , and storability of such lithium secondary batteries . For example , patent document 1 includes a state ment to the effect that when an electrolyte containing a Fourthly , various investigations have been made on non vinylethylene carbonate compound is used , the decomposi aqueous solvents and electrolytes in order to improve the tion of this electrolyte is minimized and a battery excellent battery characteristics including load characteristics , cycle 40 in storability and cycle characteristics can be fabricated . characteristics , and storability of such nonaqueous- electro Patent document 2 includes a statement to the effect that lyte batteries or to enhance the safety of such batteries when an electrolyte containing propanesultone is used , during heating or at the time of short - circuiting . For recovery capacity after storage can be increased . example , sulfolane combines a high permittivity and high However , incorporation of such compounds has had a electrochemical oxidation stability even in nonaqueous sol- 45 problem that although the incorporation has the effect of vents and a boiling point as high as 278° C . , which is higher improving storability and cycle characteristics to some than those of ethylene carbonate and propylene carbonate . degree , a coating film having high resistance is formed on Sulfolane can hence be expected to contribute to an the negative - electrode side and this , in particular, reduces improvement in battery safety when used as a solvent. discharge load characteristics . However , sulfolane has a melting point as high as 28° C . and 50 Patent Document 1 : JP - A - 2001 - 006729 there has been a problem that a battery employing sulfolane Patent Document 2 : JP - A - 10 -050342 as a main solvent has impaired low -temperature character - Patent Document 3 : JP - A - 2004 - 363077 istics . Furthermore , it is known that sulfolane has poor Patent Document 4 : JP - A - 7 - 176322 compatibility with graphite - based negative electrodes and Patent Document 5 : JP - A - 2000 -012078 that use of sulfolane as a main solvent results in a charged 55 Patent Document 6 : JP - A - 2004 - 296389 discharge capacity lower than a theoretical capacity . Patent Document 7 : JP - A - 9 - 245832 For example , patent document 5 discloses that in a Non - Patent Document 1 : Kikan Kagaku Sosetsu , No . 49 , p . nonaqueous - electrolyte secondary battery employing the 108 electrolyte described therein , the electrolyte can be pre vented from solidifying at low temperatures by using a 60 DISCLOSURE OF THE INVENTION mixed solvent composed of sulfolane and ethyl methyl carbonate . Problems that the Invention is to Solve Patent document 6 discloses that when sulfolane and y -butyrolactone are used as main solvents and vinylethylene < Nonaqueous Electrolyte 1 and Nonaqueous- Electrolyte carbonate and vinylene carbonate are added thereto , then a 65 Secondary Battery 1 > coating film of satisfactory quality which has high lithium An object of the invention , which has been achieved in ion permeability is formed on the surface of the graphite - view of the background art described above, is to provide a US 9 ,853 , 326 B2 nonaqueous electrolyte for secondary batteries which has to provide a nonaqueous electrolyte for secondary batteries excellent discharge load characteristics and is excellent in which has excellent discharge load characteristics and is high -temperature storability and cycle characteristicsteristics. excellent in high - temperature storability and cycle charac < Nonaqueous Electrolyte 2 and Nonaqueous - Electrolyte teristics. Secondary Battery 2 > Another object of the invention , which has been achieved Means for Solving the Problems in view of the background art described above , is to provide another nonaqueous electrolyte which has excellent dis - Nonaqueous Electrolyte 1 and Nonaqueous - Electrolyte Sec charge load characteristics and is excellent in high -tempera - ondary Battery 1 ture storability and cycle characteristics . 10 The present inventors diligently made investigations in < Nonaqueous Electrolyte 3 and Nonaqueous - Electrolyte view of the problems described above . As a result , they have Secondary Battery 3 > found that a nonaqueous electrolyte which contains at least Still another object of the invention , which has been one carbonate having a halogen atom and to which a specific achieved in view of the background art described above , is compound has been added can have excellent discharge load to provide a nonaqueous electrolyte for secondary batteries 15 characteristics and can retain satisfactory high - temperature which is excellent in cycle characteristics , storability, gas storability and satisfactory cycle characteristics . Invention 1 evolution inhibition during continuous charge , and battery has been thus completed . characteristics. Namely , invention 1 resides in nonaqueous electrolyte < Nonaqueous Electrolyte 4 and Nonaqueous -Electrolyte which is a nonaqueous electrolyte for use in a nonaqueous Secondary Battery 4 > 20 electrolyte secondary battery comprising a negative elec However , the recent desire for higher performances in trode and a positive electrode which are capable of occlud batteries is growingmore and more , and it is desired to attain ing and releasing ions and a nonaqueous electrolyte , and the high capacity, high output power , high - temperature storabil - nonaqueous electrolyte comprises: an electrolyte and a non ity , cycle characteristics , high safety, etc . on a high level . aqueous solvent, wherein the nonaqueous solvent com In a nonaqueous- electrolyte secondary battery employing 25 prises : a carbonate having a halogen atom ; and a monofluo the electrolyte described in patent document 5 , the revers - rophosphate and / or a difluorophosphate . ibility of electrode reactions in initial charge/ discharge was Invention 1 further resides in nonaqueous - electrolyte sec insufficient. This battery was hence insufficient in charge ondary battery 1 which is a nonaqueous -electrolyte second discharge capacity and charge discharge efficiency ( see ary battery comprising a negative electrode and a positive Comparative Example 1 for Nonaqueous Electrolyte 4 ) . On 30 electrode which are capable of occluding/ releasing lithium the other hand , a nonaqueous - electrolyte secondary battery ions and a nonaqueous electrolyte , wherein the nonaqueous employing the electrolyte described in patent document 6 electrolyte is the nonaqueous electrolyte descried above. has had the following drawbacks. y -butyrolactone , which is Nonaqueous Electrolyte 2 and Nonaqueous- Electrolyte Sec used as a main solvent in the electrolyte , has a coefficient of ondary Battery 2 viscosity at 25° C . as high as 1. 73 mPa . s, which is higher 35 The inventors diligently made investigations in view of than those of low -molecular acyclic carbonates used as main the problems described above . As a result , they have found solvents in common electrolytes ( e . g . , dimethyl carbonate , that a nonaqueous electrolyte to which a specific compound 0 .59 mPa . s ; diethyl carbonate , 0 .75 mPa . s ; ethyl methyl has been added can have excellent discharge load charac carbonate , 0 .65 mPa . s ) . Because of this, the electrolyte as a teristics and retains satisfactory high - temperature storability whole had a high coefficient of viscosity and was unsatis - 40 and satisfactory cycle characteristics even when a solvent factory in charge discharge efficiency at a high current which has a high permittivity and a low coefficient of density . In addition , y - butyrolactone in a charged state has viscosity and has a heteroelement- containing functional poor thermal stability and the battery has had a problem group other than a carbonyl group has been used therein . concerning charge /discharge characteristics after storage at a Invention 2 has been thus completed . high temperature such as 85° C . (see Comparative Example 45 Namely , invention 2 resides in nonaqueous electrolyte 2 2 for Nonaqueous Electrolyte 4 and Comparative Example which is a nonaqueous electrolyte mainly comprising an 3 for Nonaqueous Electrolyte 4 ) . electrolyte and a nonaqueous solvent dissolving the electro Consequently , a further object of the invention is to lyte , and the nonaqueous electrolyte comprises: a compound eliminate the problem that high -current -density charge /dis - which is liquid at 25° C ., has a permittivity of 5 or higher and charge characteristics decrease when a nonaqueous electro - 50 a coefficient of viscosity of 0 . 6 cP or lower , and has a group lyte containing a cyclic sulfone compound is used and to constituting a heteroelement- containing framework ( exclud provide a nonaqueous electrolyte capable of reconciling ing carbonyl group ) ; and further a monofluorophosphate high battery performance with high safety . Still a further and /or a difluorophosphate . object is to provide a nonaqueous - electrolyte battery Invention 2 further resides in nonaqueous- electrolyte sec employing the electrolyte . 55 ondary battery 2 which is a nonaqueous - electrolyte second < Nonaqueous Electrolyte 5 and Nonaqueous - Electrolyte ary battery comprising a negative electrode and a positive Secondary Battery 5 > electrode which are capable of occluding / releasing lithium Still further objects of the invention , which has been ions and a nonaqueous electrolyte , wherein the nonaqueous achieved in view of the background art described above , are electrolyte is the nonaqueous electrolyte described above . to provide a nonaqueous electrolyte which maintains high 60 Nonaqueous Electrolyte 3 and Nonaqueous - Electrolyte Sec capacity and imparts satisfactory continuous - charge charac - ondary Battery 3 teristics and to provide a nonaqueous- electrolyte secondary The inventors diligently made investigations in view of battery . the problems described above . As a result, they have found 65 battery characteristics can be kept satisfactory when at least Still a further object of the invention , which has been one compound selected from the group consisting of com achieved in view of the background art described above, is pounds represented by general formula ( 1 ) , nitrile com US 9 ,853 , 326 B2 pounds, isocyanate compounds, phosphazene compounds, Invention 4 further resides in nonaqueous - electrolyte sec disulfonic acid ester compounds, sulfide compounds, disul- ondary battery 4 which is a nonaqueous- electrolyte second fide compounds, acid anhydrides, lactone compounds hav ary battery comprising a negative electrode and a positive ing a substituent in the a -position , and compounds having a electrode which are capable of occluding/ releasing lithium carbon -carbon triple bond is further added to a nonaqueous 5 ions and a nonaqueous electrolyte , wherein the nonaqueous electrolyte containing a monofluorophosphate and /or a dif electrolyte is the nonaqueous electrolyte described above . luorophosphate . Invention 3 has been thus completed . Nonaqueous Electrolyte 5 and Nonaqueous -Electrolyte Sec Namely , invention 3 provides nonaqueous electrolyte 3 which is a nonaqueous electrolyte mainly comprising an ondary Battery 5 electrolyte and a nonaqueous solvent dissolving the electro - 10 The inventors diligently made investigations in order to lyte , and the nonaqueous electrolyte comprises: a monofluo - eliminate the problems described above . As a result , they rophosphate and /or a difluorophosphate ; and further at least have found that high - temperature continuous- charge char one compound selected from the group consisting of com acteristics are greatly improved while maintaining high pounds represented by the following general formula ( 1 ) , 15 capacity , by incorporating a cyclic polyamine compound nitrile compounds , isocyanate compounds, phosphazene and /or a cyclic polyamide compound into a nonaqueous compounds , disulfonic acid ester compounds, sulfide com pounds, disulfide compounds, acid anhydrides, lactone com electrolyte and optionally further adding a specific com pounds having a substituent in the Q -position , and com pound , e .g ., an unsaturated carbonate . Invention 5 has been pounds having a carbon -carbon triple bond ( the compound 20 thus" completed . is hereinafter sometimes referred to as " compound A of the Namely , invention 5 resides in nonaqueous electrolyte 5 invention ” ): which is a nonaqueous electrolyte comprising a lithium salt and a nonaqueous organic solvent dissolving the lithium salt , wherein the nonaqueous organic solvent comprises: a cyclic [ Chemical Formula - 1 ] polyamine compound and / or a cyclic polyamide compound ; and further at least one compound selected from the group consisting of unsaturated carbonates, fluorine -containing R — P - R3 carbonates , monofluorophosphates, and difluorophosphates . 30 Hereinafter, this invention is referred to as “ embodiment 5 - 1 ” . [wherein R ' , R ? , and R3 each independently represent a Invention 5 further resides in a nonaqueous electrolyte fluorine atom , an alkyl group which has 1 - 12 carbon atoms which comprises a lithium salt and a nonaqueous organic and may be substituted with a fluorine atom , or an alkoxy 35 solvent dissolving the lithium salt, wherein the nonaqueous group which has 1 - 12 carbon atoms and may be substituted organic solvent comprises : a cyclic polyamine compound ; with a fluorine atom ]. and further a cyclic carbonate in an amount of from 5 % by Invention 3 further provides nonaqueous - electrolyte sec ondary battery 3 which is a nonaqueous - electrolyte second mass to 40 % by mass based on the whole nonaqueous ary battery at least comprising a negative electrode and a 40 organic2 solvent. Hereinafter , this invention is referred to as positive electrode which are capable of occluding and “ embodiment 5 - 2 ” . releasing lithium ions and a nonaqueous electrolyte , wherein Invention 5 further resides in a nonaqueous electrolyte the nonaqueous electrolyte is the nonaqueous electrolyte which comprises a lithium salt and a nonaqueous organic described above . solvent dissolving the lithium salt , wherein the nonaqueous Nonaqueous Electrolyte 4 and Nonaqueous - Electrolyte Sec - 45 organic solvent comprises a cyclic polyamide compound . ondary Battery 4 Hereinafter, this invention is referred to as “ embodiment The inventors diligently made investigations in order to 5 - 3 " . eliminate the problems described above. As a result, they Invention 5 still further resides in nonaqueous- electrolyte have found that high -current - density charge /discharge char - secondary battery 5 characterized by employing any of the acteristics can be inhibited from decreasing and high battery 50 nonaqueous electrolytes described above . performance can be reconciled with high safety by using a compound having a coefficient of viscosity not higher than Nonaqueous Electrolyte 6 and Nonaqueous- Electrolyte Sec a certain upper limit together with a cyclic sulfone com ondary Battery 6 pound as a main solvent in a nonaqueous electrolyte and by The inventors diligently made investigations in view of further incorporating a specific compound . Invention 4 has 55 the problems described above . As a result , they have found been thus completed . that a nonaqueous electrolyte to which a specific disulfo Namely, invention 4 resides in nonaqueous electrolyte nylimide salt and a specific compound have been added can which is a nonaqueous electrolyte comprising an electrolyte have excellent discharge load characteristics and retain and a nonaqueous solvent dissolving the electrolyte , the satisfactory high -temperature storability and satisfactory nonaqueous electrolyte comprising : a cyclic sulfone com - 60 cycle characteristics . Invention 6 has been thus completed . pound in an amount of 10 - 70 % by volume based on the Namely , invention 6 resides in nonaqueous electrolyte 6 whole nonaqueous solvent ; a compound having a coefficient which is a nonaqueous electrolyte mainly comprising an of viscosity at 25° C . of 1 . 5 mPa. s or lower ; and further at electrolyte and a nonaqueous solvent dissolving the electro least one compound selected from the group consisting of lyte , the nonaqueous electrolyte comprising : at least one carbonates having an unsaturated bond , carbonates having a 65 cyclic disulfonylimide salt represented by the following halogen atom , monofluorophosphates , and difluorophos - general formula ( 1 ) ; and further a monofluorophosphate phates . and / or a difluorophosphate : US 9, 853, 326 B2 10 < Nonaqueous Electrolyte 6 and Nonaqueous -Electrolyte [Chemical Formula - 2 ] Secondary Battery 6 ( 1 ) According to invention 6 , nonaqueous electrolyte 6 for , secondary batteries and nonaqueous - electrolyte secondary / 5 battery 6 can be provided , which have excellent discharge load characteristics and are excellent also in high -tempera Mn+ ture storability and cycle characteristics . BEST MODE FOR CARRYING OUT THE 10 INVENTION [wherein R represents an alkylene group which has 1 - 12 Embodiments of the invention will be explained below in carbon atoms and may be substituted with an alkyl group , and the alkyl group and the alkylene group may be substi detail. The following explanations on constituent elements tuted with a fluorine atom ; n is an integer of 1 to 3 ; and M 15 are for embodiments ( typical embodiments ) of the inven is one or more metals selected from Group 1 , Group 2 , and tion , and the invention should not be construed as being Group 13 of the periodic table or a quaternary onium ]. limited to the contents thereof. Various modifications of the Invention 6 further resides in nonaqueous -electrolyte sec invention can be made within the spirit of the invention . ondary battery 6 which is a nonaqueous - electrolyte second < Nonaqueous Electrolyte 1 and Nonaqueous -Electrolyte ary battery comprising a negative electrode and a positive 20 Secondary Battery 1 ) electrode which are capable of occluding / releasing lithium [1 . Nonaqueous Electrolyte 1 for Secondary Battery ] ions and a nonaqueous electrolyte , wherein the nonaqueous Nonaqueous electrolyte 1 of the invention includes an electrolyte is the nonaqueous electrolyte described above . electrolyte and a nonaqueous solvent which contains the electrolyte dissolved therein , like ordinary electrolytes . Advantages of the Invention 25 < 1 - 1 . Electrolyte > The electrolyte to be used in nonaqueous electrolyte 1 of < Nonaqueous Electrolyte 1 and Nonaqueous - Electrolyte the invention is not limited , and known ones for use as Secondary Battery 1 > electrolytes in a target nonaqueous - electrolyte secondary According to invention 1 , nonaqueous electrolyte 1 for battery can be employed and mixed at will . In the case where secondary batteries and nonaqueous - electrolyte secondary 30 nonaqueous electrolyte 1 of the invention is to be used in battery 1 can be provided , which are excellent in discharge nonaqueous- electrolyte secondary battery 1 , the electrolyte load characteristics , high - temperature storability , and cycle preferably is one or more lithium salts . characteristics . Examples of the electrolyte include < Nonaqueous Electrolyte 2 and Nonaqueous -Electrolyte inorganic lithium salts such as LiC104, LiAsF ., LiPF , Secondary Battery 2 > 35 Li_ CO3 , and LiBF4; According to invention 2 , nonaqueous electrolyte 2 and fluorine -containing organic lithium salts such as LiCF3SO3, nonaqueous -electrolyte secondary battery 2 can be provided , LiN (CF2SO2 ) 2, LiN (C2F5502 ) 2, LiN (CF2SO2 ) (CAF , 802) , which have excellent discharge load characteristics and are LiC (CF2SO2 ) 3, LiPF4 ( CF3) 2 , LiPF4 (C2F5 )2 , LiPF4 excellent in high -temperature storability and cycle charac (CFzS02 ) 2 , LiPF4 (C2F - S02) 2 , LiBFZ (CF3 ) , LiBF3 (C2F3 ) , teristics . 40 LiBF ( CF3) 2 , LiBF , C , F3) 2 , LiBFZ (CF2SO2 ) 2, and L?BF , < Nonaqueous Electrolyte 3 and Nonaqueous- Electrolyte (C2F5S02 ) 2 ; Secondary Battery 3 > dicarboxylic - containing acid complex lithium salts such as According to invention 3 , nonaqueous electrolyte 3 and lithium bis (oxalato ) borate , lithium tris (oxalato )phosphate , nonaqueous - electrolyte secondary battery 3 can be provided , and lithium difluorooxalatoborate; and which are excellent in cycle characteristics , storability , gas 45 sodium salts or potassium salts such as KPF . , NaPF , evolution inhibition during continuous charge , and battery NaBF4, and CF2S0zNa and the like. characteristics . Preferred of these is LiPFæ , LiBFL2, LiCF SO , LiN < Nonaqueous Electrolyte 4 and Nonaqueous- Electrolyte (CF3S02 ) 2 , LiN ( C2F SO2) 2 , or lithium bis ( oxalato ) borate . Secondary Battery 4 > Especially preferred is LiPF6 or LiBF4 . In invention 4 , the solvent to be mixed with a cyclic 50 One electrolyte may be used alone , or any desired com sulfone compound has a coefficient of viscosity as low as 1 . 5 bination of two or more electrolytes may be used in any mPa ·s or below and the nonaqueous electrolyte as a whole desired proportion . In particular , a combination of two has a lower coefficient of viscosity than that according to specific inorganic lithium salts or a combination of an patent document 6 . High - current- density charge / discharge inorganic lithium salt and a fluorine -containing organic capacity can hence be prevented from decreasing . Namely , 55 lithium salt is preferred because use of this combination is according to invention 4 , nonaqueous - electrolyte battery 4 effective in inhibiting gas evolution during continuous can be provided, which compares ordinary electrolytes in charge or inhibiting deterioration through high - temperature high capacity , high -current - density charge /discharge char- storage . acteristics , and storability and has far higher safety than the It is especially preferred to use a combination of LiPF general electrolytes . Consequently , not only size increase 60 and LiBF , or a combination of an inorganic lithium salt , e . g . , and performance advancement but also higher safety can be LiPF6 or LiBF4 , and a fluorine - containing organic lithium attained in nonaqueous - electrolyte batteries . salt, e . g . , LiCF3SO3, LiN ( CF3S02) 2 , or LiN (C2F3S02 ) 2 . tion , it is preferred that the proportion of the LiBF , con According to invention 5 , nonaqueous - electrolyte second - 65 tained should be generally 0 .01 % by mass or higher and ary battery 5 can be provided , which retains a high capacity generally 20 % by mass or lower based on all electrolytes. and is excellent in continuous -charge characteristics , etc . LiBF4 has a low degree of dissociation , and too high US 9 ,853 , 326 B2 12 proportions thereof may result in cases where nonaqueous " carbonate having a halogen atom ” has two or more halogen electrolyte 1 has increased resistance . atoms per molecule , these atoms may be the same or On the other hand, in the case where an inorganic lithium different. salt , e . g ., LiPF , or LiBF , and a fluorine - containing organic < 1 -2 - 1 . Cyclic Carbonate > lithium salt , e . g . , LiCF , SO . , LiN (CF . SO , ) . . or LiN 5 The cyclic carbonate to be used as the “ carbonate having (CF _ SO , ) , are used in combination , it is desirable that the a halogen atom ” in invention 1 is explained below . The number of the atoms constituting the ring of the cyclic proportion of the inorganic lithium salt in all lithium salts carbonate is generally 4 or larger , preferably 5 or larger , and should be in the range of from generally 70 % by mass to the upper limit thereof is preferably 10 or smaller, especially generally 99 % by mass . Since fluorine - containing organic 10 preferably 8 or smaller . When the number thereof is outside lithium salts generally have a higher molecular weight than the range , there are cases where this compound poses a inorganic lithium salts , too high proportions of the organic problem concerning the chemical stability or industrial lithium salt in that combination results in a reduced propor availability thereof. Examples of such cyclic carbonates in tion of the nonaqueous solvent in the whole nonaqueous which the numbers of ring - constituting atoms are from 5 to electrolyte 1 . There are hence cases where nonaqueous 15 8 include ethylene carbonate . 1 . 3 - propanediol carbonate , electrolyte 1 has increased resistance. 1 , 4 -butanediol carbonate , and 1 , 5 - pentanediol carbonate , The lithium salt concentration in the final composition of respectively . The cyclic carbonate may have a carbon nonaqueous electrolyte 1 of the invention may be any carbon unsaturated bond in the ring . Examples thereof desired value unless this concentration value considerably include vinylene carbonate and cis - 2 -butene - 1 , 4 -diol car lessens the effect of the invention . However , the lithium salt 20 bonate and the like . concentration therein is generally 0 . 5 mol/ L or higher, The cyclic carbonate may have one or more substituents preferably 0 .6 mol/ L or higher, more preferably 0 . 8 mol/ L or each constituted of a hydrocarbon group . This hydrocarbon higher, and is generally 3 mol/ L or lower , preferably 2 mol/ L group is not limited in the kind thereof, and may be an or lower , more preferably 1 . 5 mol/ L or lower. When the aliphatic hydrocarbon group or an aromatic hydrocarbon concentration thereof is too low , there are cases where 25 group or may be a hydrocarbon group including these two nonaqueous electrolyte 1 has insufficient electrical conduc - kinds of groups bonded to each other. In the case of an tivity . When the concentration thereof is too high , a viscosity aliphatic hydrocarbon group , this group may be an acyclic or increase occurs and this reduces electrical conductivity . cyclic group or may be a structure including an acyclic There are hence cases where the nonaqueous - electrolyte moiety and a cyclic moiety bonded thereto . In the case of an secondary battery employing this nonaqueous electrolyte 1 30 acyclic hydrocarbon group , this group may be linear or of the invention has reduced performance . branched . The hydrocarbon group may be a saturated hydro Especially in the case where the nonaqueous solvent of carbon group or may have an unsaturated bond . nonaqueous electrolyte 1 consists mainly of one or more Examples of the hydrocarbon group include alkyl groups, carbonate compounds such as alkylene carbonates or dialkyl cycloalkyl groups, and hydrocarbon groups having an carbonates , use of LiPF , in combination with LiBF , is 35 unsaturated bond ( hereinafter suitably referred to as “ unsatu preferred although LiPF , may be used alone . This is because rated hydrocarbon groups ' ) . use of that combination inhibits capacity from deteriorating Examples of the alkyl groups include methyl, ethyl , with continuous charge . When these two salts are used in 1 -propyl , 1 -methylethyl , 1 -butyl , 1 -methylpropyl , 2 -meth combination , the molar ratio of LiBF4 to Lipfo is generally ylpropyl, and 1 , 1 -dimethylethyl . 0 . 005 or higher, preferably 0 .01 or higher , especially pref - 40 Preferred of these is methyl or ethyl and the like. erably 0 .05 or higher, and is generally 0 . 4 or lower, prefer - Examples of the cycloalkyl groups include cyclopentyl, ably 0 . 2 or lower . In case where the molar ratio thereof is too 2 -methylcyclopentyl , 3 -methylcyclopentyl , 2 , 2 - dimethylcy high , battery characteristics tend to decrease through high clopentyl, 2 , 3 - dimethylcyclopentyl, 2 , 4 - dimethylcyclopen temperature storage . Conversely , too low molar ratios tyl, 2 , 5 - dimethylcyclopentyl, 3 , 3 -dimethylcyclopentyl , 3 , 4 thereof result in difficulties in obtaining the effect of inhib - 45 dimethylcyclopentyl, 2 -ethylcyclopentyl , iting gas evolution during continuous charge or inhibiting 3 - ethylcyclopentyl , cyclohexyl, 2 -methylcyclohexyl , capacity deterioration . 3 -methylcyclohexyl , 4 -methylcyclohexyl , 2 , 2 -dimethylcy In the case where the nonaqueous solvent of nonaqueous clohexyl, 2 , 3 - dimethylcyclohexyl, 2 , 4 -dimethylcyclohexyl , electrolyte 1 includes at least 50 % by volume cyclic car 2 ,5 -dimethylcyclohexyl , 2 ,6 -dimethylcyclohexyl , 3 ,4 -dim boxylic ester compound such as , e . g ., y - butyrolactone or 50 ethylcyclohexyl, 3 ,5 - dimethylcyclohexyl, 2 -ethylcyclo y - valerolactone , it is preferred that LiBF4 should account for hexyl, 3 - ethylcyclohexyl, 4 -ethylcyclohexyl , bicyclo [ 3 .2 . 1 ] 50 mol % or more of all electrolytes . oct- 1 -yl , and bicyclo [ 3 . 2 . 1 ] oct - 2 - yl and the like . < 1 - 2 . Carbonate Having Halogen Atom > Preferred of these is cyclopentyl or cyclohexyl . The " carbonate having a halogen atom ” in invention 1 is Examples of the unsaturated hydrocarbon groups include not particularly limited so long as the carbonate has a 55 vinyl , 1- propen -1 - yl, 1- propen -2 - yl, allyl, crotyl, ethynyl, halogen atom , and any desired such carbonate can be used . propargyl, phenyl, 2 -methylphenyl , 3 -methylphenyl , Preferred examples the “ carbonate having a halogen atom ” 4 -methylphenyl , 2 , 3 - dimethylphenyl, xylyl , phenylmethyl, include cyclic carbonates having a halogen atom or acyclic 1 -phenylethyl , 2 - phenylethyl , diphenylmethyl, triphenylm carbonates having a halogen atom . ethyl, and cinnamyl and the like . Examples of the halogen atoms include fluorine , chlorine , 60 Preferred of these is vinyl, allyl, phenyl , phenylmethyl, or bromine , and iodine atoms. More preferred of these are 2 -phenylethyl . fluorine atoms or chlorine atoms. Especially preferred are The hydrocarbon group may be substituted with one or fluorine atoms . The number of halogen atoms possessed by more substituents . The kinds of the substituents are not the " carbonate having a halogen atom " per molecule is not limited unless the substituents considerably lessen the particularly limited so long as the number thereof is 1 or 65 effects of invention 1 . Examples of the substituents include larger. However, the number thereof is generally 10 or hydroxyl groups, amino groups, nitro groups , cyano groups , smaller , preferably 6 or smaller . In the case where the carboxyl groups , ether groups, and aldehyde groups . The US 9 ,853 , 326 B2 14 hydrocarbon group may have been bonded to the cyclic methyl, ( 3 - fluorophenyl) methyl , ( 4 - fluorophenyl) methyl , carbonate through an oxygen atom . In the case where the ( 2 - fluorophenyl) fluoromethyl, 1 - fluoro - 2 - phenylethyl, 1 , 1 hydrocarbon group has two or more substituents , these difluoro - 2 -phenylethyl , 1 ,2 - fluoro -2 -phenylethyl , 2 - (2 - fluo substituents may be the same or different. rophenyl) ethyl, 2 - ( 3 - fluorophenyl) ethyl, 2 - (4 - fluorophenyl) When any two or more of such hydrocarbon groups are 5 ethyl, 1 - fluoro -2 - (2 - fluorophenyl )ethyl , 1 - fluoro - 2 -( 2 compared , the hydrocarbon groups may be the same or fluorophenylethyl, different. When such hydrocarbon groups have a substituent, 1 -chlorovinyl , 2 - chlorovinyl, 1 , 2 - dichlorovinyl, perchloro these substituted hydrocarbon groups including the substitu vinyl , 1 - chloroallyl, 2 - chloroallyl, 3 -chloroallyl , 2 - chloro ents may be the same or different. Furthermore , any desired phenyl, 3 -chlorophenyl , 4 -chlorophenyl , 2, 3 - dichlorophe two or more of such hydrocarbon groups may be bonded to 10 nyl, 2 , 4 - dichlorophenyl, 2 , 5 - dichlorophenyl , 2 , 6 each other to form a cyclic structure . dichlorophenyl, 3 , 4 - dichlorophenyl, 1 , 5 -dichlorophenyl , The number of carbon atoms of the hydrocarbon group is 1 - chloro - 1 - phenylmethyl, 1 , 1 - dichloro - 1 -phenylmethyl , generally 1 or larger and is generally 20 or smaller , prefer - (2 - chlorophenyl)methyl , (3 -chlorophenyl )methyl , ( 4 -chlo ably 10 or smaller , more preferably 6 or smaller. When the rophenyl) methyl , ( 2 -chlorophenyl ) chloromethyl , 1 -chloro number of carbon atoms of the hydrocarbon group is too 15 2 -phenylethyl , 1 , 1 - dichloro - 2 - phenylethyl, 1 , 2 - chloro - 2 large , the number of moles per unit weight is too small and phenylethyl, 2 - ( 2 - chlorophenyl) ethyl , 2 - ( 3 - chlorophenyl) there are cases where various effects are reduced . In the case ethyl, 2 - (4 - chlorophenyl) ethyl , 1 - chloro - 2 - ( 2 - chlorophenyl) where the hydrocarbon group has substituents , the number ethyl, and 1 - chloro - 2 - ( 2 - chlorophenyl) ethyl and the like . of carbon atoms of the substituted hydrocarbon group Preferred of these is 2 - fluorophenyl, 3 - fluorophenyl, including these substituents is generally within that range . 20 4 - fluorophenyl, 2 , 4 - difluorophenyl, 3 , 5 -difluorophenyl , The cyclic carbonate having a halogen atom may be one 1 - fluoro - 1 - phenylmethyl, ( 2 - fluorophenyl) methyl , ( 4 - fluo which has halogen atoms directly bonded to carbon atoms rophenyl) methyl , (2 - fluorophenyl) fluoromethyl , 1 - fluoro -2 constituting the cyclic structure or may be one which has phenylethyl, 2 -( 2 - fluorophenyl) ethyl, or 2 - (4 - fluorophenyl) halogen atoms bonded to the " substituent constituted of a ethyl. hydrocarbon group ” described above . Alternatively , the 25 Specific examples of such cyclic carbonates having a cyclic carbonate may be one which has halogen atoms halogen atom include respectively bonded to both of those . fluoroethylene carbonate , chloroethylene carbonate , 4 , 4 - di In the case where the structure composed of the " sub - fluoroethylene carbonate , 4 ,5 - difluoroethylene carbonate , stituent constituted of a hydrocarbon group ” and a halogen 4 ,4 -dichloroethylene carbonate , 4 ,5 - dichloroethylene car atom bonded thereto is a halogenated alkyl group , examples 30 bonate , 4 - fluoro -4 -methylethylene carbonate , 4 -chloro - 4 thereof include methylethylene carbonate , 4 - fluoro - 5 -methylethylene car monofluoromethyl , difluoromethyl, trifluoromethyl, 1 - fluo bonate , 4 -chloro - 5 -methylethylene carbonate , 4 , 5 -difluoro roethyl, 2 - fluoroethyl, 1 , 1 - difluoroethyl , 1 , 2 - difluoroethyl, 4 -methylethylene carbonate , 4 , 5 -dichloro - 4 -methylethylene 2 , 2 -difluoroethyl , 2 , 2 , 2 - trifluoroethyl, perfluoroethyl, mono carbonate , 4 - fluoro - 5 -methylethylene carbonate , 4 - chloro - 5 chloromethyl, dichloromethyl, trichloromethyl, 1 - chloro - 35 methylethylene carbonate, 4 , 4 -difluoro - 5 -methylethylene ethyl, 2 - chloroethyl , 1 , 1 -dichloroethyl , 1 , 2 - dichloroethyl, carbonate , 4 , 4 - dichloro - 5 -methylethylene carbonate , 2 , 2 -dichloroethyl , 2 , 2 , 2 - trichloroethyl , and perchloroethyl 4 - ( fluoromethyl) ethylene carbonate , 4 - ( chloromethyl) ethyl and the like. ene carbonate , 4 - ( difluoromethyl) ethylene carbonate, 4 - ( di Preferred of these is monofluoromethyl, difluoromethyl, chloromethyl) ethylene carbonate , 4 - ( trifluoromethyl) ethyl trifluoromethyl, 2 , 2 -difluoroethyl , 2 , 2 , 2 - trifluoroethyl, or 40 ene carbonate , 4 - ( trichloromethyl) ethylene carbonate , perfluoroethyl. 4 - ( fluoromethyl) - 4 - fluoroethylene carbonate , 4 - (chlorom In the case where the structure composed of the “ sub - ethyl) - 4 - chloroethylene carbonate , 4 - ( fluoromethyl) - 5 - fluo stituent constituted of a hydrocarbon group ” and a halogen roethylene carbonate , 4 - chloromethyl) - 5 - chloroethylene atom bonded thereto is a halogenated cycloalkyl group , carbonate, 4 - fluoro - 4 , 5 -dimethylethylene carbonate , examples thereof include 45 4 -chloro -4 , 5 - dimethylethylene carbonate , 4 , 5 -difluoro - 4 , 5 1 - fluorocyclopentyl, 2 - fluorocyclopentyl, 3 - fluorocyclopen dimethylethylene carbonate , 4 , 5 - dichloro - 4 , 5 - dimethyleth tyl, difluorocyclopentyl, trifluorocyclopentyl, 1 - fluorocyclo ylene carbonate, 4 , 4 - difluoro - 5 , 5 - dimethylethylene carbon hexyl , 2 - fluorocyclohexyl, 3 - fluorocyclohexyl, 4 - fluorocy ate , and 4 , 4 -dichloro - 5 , 5 - dimethylethylene carbonate and clohexyl, difluorocyclohexyl, trifluorocyclohexyl, the like . 1 - chlorocyclopentyl, 2 - chlorocyclopentyl, 3 - chlorocyclo - 50 Examples of the " cyclic carbonate having a halogen pentyl, dichlorocyclopentyl, trichlorocyclopentyl, 1 - chloro atom ” which has a carbon - carbon unsaturated bond in the cyclohexyl, 2 -chlorocyclohexyl , 3 - chlorocyclohexyl, ring include 4 - chlorocyclohexyl , dichlorocyclohexyl, and trichlorocyclo fluorovinylene carbonate , 4 - fluoro - 5 -methylvinylene car hexyl and the like . bonate , 4 - fluoro - 5 -phenylvinylene carbonate , 4 - ( trifluorom Preferred of these is 1 - fluorocyclopentyl, 2 - fluorocyclo - 55 ethyl) vinylene carbonate , chlorovinylene carbonate , pentyl , 3 - fluorocyclopentyl, 1 - fluorocyclohexyl, 2 - fluorocy 4 -chloro - 5 -methylvinylene carbonate , 4 - chloro - 5 -phenylvi clohexyl, 3 - fluorocyclohexyl, or 4 - fluorocyclohexyl. nylene carbonate , and 4 - ( trichloromethyl) vinylene carbon In the case where the structure composed of the “ sub - ate and the like . stituent constituted of a hydrocarbon group ” and a halogen Examples of the cyclic carbonate substituted with one or atom bonded thereto is a halogenated unsaturated hydrocar - 60 more hydrocarbon groups and having one or more carbon bon group , examples thereof include carbon unsaturated bonds outside the ring include 4 - fluoro 1 - fluorovinyl, 2 - fluorovinyl, 1 , 2 - difluorovinyl , perfluorovi 4 - vinylethylene carbonate , 4 - fluoro - 5 - vinylethylene carbon nyl, 1 - fluoroallyl, 2 - fluoroallyl, 3 - fluoroallyl , 2 - fluorophe ate , 4 ,4 -difluoro - 5 -vinylethylene carbonate , 4 , 5 -difluoro -4 nyl, 3 -fluorophenyl , 4 - fluorophenyl, 2 ,3 -difluorophenyl , vinylethylene carbonate , 4 -chloro - 5 -vinylethylene 2 ,4 - difluorophenyl, 2 , 5 -difluorophenyl , 2 , 6 - difluorophenyl , 65 carbonate , 4 , 4 - dichloro - 5 - vinylethylene carbonate , 4 , 5 - di 3 , 4 - difluorophenyl, 3 , 5 - difluorophenyl, 1 - fluoro - 1 - phenyl- chloro - 4 - vinylethylene carbonate , 4 - fluoro - 4 , 5 - divinyleth methyl, 1 , 1 - difluoro - 1 - phenylmethyl, ( 2 - fluorophenyl ) ylene carbonate , 4 , 5 -difluoro - 4 , 5 -divinylethylene carbonate , US 9 ,853 , 326 B2 15 16 4 - chloro - 4 , 5 - divinylethylene carbonate , 4 , 5 - dichloro - 4 , 5 - di- In the case where the cyclic carbonate having a halogen vinylethylene carbonate , 4 - fluoro - 4 - phenylethylene carbon atom is used as a nonaqueous solvent, the content thereof is ate , 4 - fluoro - 5 -phenylethylene carbonate , 4 , 4 -difluoro - 5 generally 10 % by mass or higher, preferably 12 % by mass phenylethylene carbonate , 4 , 5 - difluoro - 4 -phenylethylene or higher , most preferably 15 % by mass or higher , and is carbonate , 4 - chloro - 4 - phenylethylene carbonate , 4 - chloro - 5 generally 100 % by mass or lower, preferably 80 % by mass 5 -phenylethylene carbonate , 4 , 4 -dichloro - 5 - phenylethylene or lower , most preferably 50 % by mass or lower, based on carbonate , 4 , 5 - dichloro - 4 -phenylethylene carbonate , 4 , 5 - di- the whole nonaqueous solvent. When the content thereof is fluoro -4 , 5 - diphenylethylene carbonate , 3 , 5 -dichloro -4 , 5 -di - lower than the lower limit , there are cases where the phenylethylene carbonate , 4 - fluoro - 5 - vinylvinylene carbon - oxidative decomposition of other components of nonaque ate and , 4 - chloro - 5 - vinylvinylene carbonate and the like . 10 ous electrolyte 1 which proceeds on the surface of the Preferred of those cyclic carbonates having a halogen positive electrode is not inhibited to a desirable degree , atom are the carbonates having a fluorine atom . In particular, making it impossible to produce the effects of invention 1 . fluoroethylene carbonate, 4 , 4 -difluoroethylene carbonate , On the other hand , contents thereof higher than the upper 4 , 5 -difluoroethylene carbonate , 4 - fluoro - 4 -methylethylene limit result in an increased viscosity of the electrolyte and carbonate , 4 - fluoro -5 -methylethylene carbonate , 4 -( fluo - 15 there are hence cases where the increased viscosity reduces romethyl) -ethylene carbonate , or 4 - ( trifluoromethyl) - ethyl - various characteristics of the battery . ene carbonate is more preferred from the standpoints of The cyclic carbonate having a halogen atom may be used industrial availability and chemical stability . as a mixture with the acyclic carbonate having a halogen The molecular weight of the cyclic carbonate having a atom which will be described later and /or the “ nonaqueous halogen atom is not particularly limited , and may be any 20 solvent other than the carbonates having a halogen atom ” value unless the effects of invention 1 are considerably which will be described later , in any desired proportion . lessened thereby. However, the molecular weight thereof is Examples of combinations in the case of employing such a generally 50 or higher, preferably 80 or higher, and is mixture include : generally 250 or lower , preferably 150 or lower. When the a cyclic carbonate having a halogen atom and a cyclic cyclic carbonate has too high a molecular weight, this cyclic 25 carbonate having no halogen atoms; a cyclic carbonate carbonate having a halogen atom has reduced solubility in having a halogen atom and an acyclic carbonate having no nonaqueous electrolyte 1 and there are cases where it is halogen atoms; a cyclic carbonate having a halogen atom difficult to sufficiently produce the effects of invention 1 . and an acyclic carbonate having a halogen atom ; a cyclic Processes for producing the cyclic carbonate having a carbonate having a halogen atom and a cyclic carboxylic halogen atom also are not particularly limited . The cyclic 30 acid ester, a cyclic carbonate having a halogen atom and an carbonate can be produced by a known process selected at acyclic carboxylic acid ester ; a cyclic carbonate having a will. halogen atom and a cyclic ether ; a cyclic carbonate having Any one of those cyclic carbonates having a halogen atom a halogen atom and an acyclic ether; a cyclic carbonate explained above may be contained alone in nonaqueous having a halogen atom and a phosphorus- containing organic electrolyte 1 of the invention , or any desired combination of 35 solvent; a cyclic carbonate having a halogen atom , a cyclic two or more of these may be contained in any desired carbonate having no halogen atoms, and an acyclic carbon proportion . The content of the cyclic carbonate ( s ) having a ate having no halogen atoms; a cyclic carbonate having a halogen atom is not particularly limited . However , the halogen atom , a cyclic carbonate having no halogen atoms, content thereof is generally from 0 . 001 % by mass to 100 % and an acyclic carbonate having a halogen atom ; a cyclic by mass . 40 carbonate having a halogen atom , a cyclic carbonate having It is thought that the cyclic carbonate having a halogen no halogen atoms, and a cyclic carboxylic acid ester ; a cyclic atom performs different functions according to the content carbonate having a halogen atom , a cyclic carbonate having thereof. Factors in this have not been elucidated in detail. no halogen atoms, and an acyclic carboxylic acid ester ; a Although the scope of invention 1 should not be construed cyclic carbonate having a halogen atom , a cyclic carbonate as being limited by the factors , the following is thought. In 45 having no halogen atoms, and a cyclic ether; a cyclic the case where the cyclic carbonate having a halogen atom carbonate having a halogen atom , a cyclic carbonate having is used as an additive in an amount of from 0 .001 % by mass no halogen atoms, and an acyclic ether; a cyclic carbonate to 10 % by mass based on the whole nonaqueous solvent, this having a halogen atom , a cyclic carbonate having no halogen cyclic carbonate is thought to decompose on the surface of atoms, an acyclic carbonate having no halogen atoms, and the negative electrode to form a protective film for protect- 50 an acyclic carbonate having a halogen atom ; a cyclic car ing the surface of the negative electrode . On the other hand , bonate having a halogen atom , a cyclic carbonate having no in the case where the cyclic carbonate having a halogen atom halogen atoms, a cyclic carboxylic acid ester , and an acyclic is used as a nonaqueous solvent in an amount of from 10 % carbonate having no halogen atoms; a cyclic carbonate by mass to 100 % by mass , this cyclic carbonate is thought having a halogen atom , a cyclic carbonate having no halogen to not only perform that function of an additive but also 55 atoms, an acyclic carboxylic acid ester, and an acyclic perform the function of improving the oxidation resistance carbonate having no halogen atoms; a cyclic carbonate of nonaqueous electrolyte 1 . having a halogen atom , a cyclic carbonate having no halogen In the case where the cyclic carbonate having a halogen atoms, a cyclic ether , and an acyclic carbonate having no atom is used as an additive, the content thereof is generally halogen atoms; a cyclic carbonate having a halogen atom , a 0 .001 % by mass or higher , preferably 0 .01 % by mass or 60 cyclic carbonate having no halogen atoms, an acyclic ether, higher, and is generally 10 % by mass or lower, preferably and an acyclic carbonate having no halogen atoms; 5 % by mass or lower , based on the whole nonaqueous a cyclic carbonate having a halogen atom , a cyclic carbonate solvent. When the content thereof is too low , there are cases having no halogen atoms, a phosphorus - containing organic where the formation of a negative - electrode coating film solvent, and an acyclic carbonate having no halogen atoms; based on the reductional decomposition of the cyclic car - 65 a cyclic carbonate having a halogen atom , a cyclic carbonate bonate is insufficient, making it impossible to impart suffi - having no halogen atoms, a cyclic carboxylic acid ester , and cient battery characteristics . an acyclic carbonate having a halogen atom ; a cyclic car US 9 ,853 , 326 B2 17 18 bonate having a halogen atom , a cyclic carbonate having no fluoromethyl carbonate, 2 - fluoroethyl difluoromethyl car halogen atoms, a cyclic carboxylic acid ester , and an acyclic bonate , ethyl trifluoromethyl carbonate , 2 - chloroethyl carbonate having no halogen atoms; a cyclic carbonate methyl carbonate , ethyl chloromethyl carbonate , 2 , 2 -dichlo having a halogen atom , a cyclic carbonate having no halogen roethyl methyl carbonate , 2 -chloroethyl chloromethyl car atoms, a cyclic carboxylic acid ester, and an acyclic carbox - 5 bonate , ethyl dichloromethyl carbonate , 2 . 2 , 2 - trichloroethyl ylic acid ester; a cyclic carbonate having a halogen atom , a methyl carbonate . 2 . 2 -dichloroethyl chloromethyl carbon cyclic carbonate having no halogen atoms, a cyclic carbox ate , 2 - chloroethyl dichloromethyl carbonate , ethyl trichlo ylic acid ester, and a cyclic ether ; a cyclic carbonate having a halogen atom , a cyclic carbonate having no halogen atoms, romethyl carbonate , a cyclic carboxylic acid ester, and a phosphorus - containing 10 ethyl 2 - fluoroethyl carbonate , ethyl 2 , 2 - difluoroethyl car organic solvent; bonate , bis ( 2 - fluoroethyl) carbonate , ethyl 2 , 2 , 2 - trifluoro a cyclic carbonate having a halogen atom , a cyclic carbonate ethyl carbonate , 2 , 2 - difluoroethyl- 2 - fluoroethyl carbonate , having no halogen atoms, a cyclic carboxylic acid ester , an bis ( 2 , 2 -difluoroethyl ) carbonate , 2 , 2 , 2 - trifluoroethyl- 2 ' acyclic carbonate having a halogen atom , and an acyclic fluoroethyl carbonate , 2 , 2 , 2 - trifluoroethyl- 2 ', 2 '- difluoroethyl carbonate having no halogen atoms: a cyclic carbonate 15 carbonate , bis ( 2 , 2 , 2 - trifluoroethyl ) carbonate , ethyl 2 -chlo having a halogen atom , a cyclic carbonate having no halogen roethyl carbonate , ethyl 2 , 2 - dichloroethyl carbonate , bis ( 2 atoms, a cyclic ether, an acyclic carbonate having a halogen chloroethyl) carbonate , ethyl 2 , 2 , 2 - trichloroethyl carbonate , atom , and an acyclic carbonate having no halogen atoms; 2 ,2 -dichloroethyl - 2 '- chloroethyl carbonate , bis (2 ,2 -dichlo and a cyclic carbonate having a halogen atom , a cyclic roethyl) carbonate , 2 , 2 , 2 - trichloroethyl- 2 - chloroethyl car carbonate having no halogen atoms, a phosphorus - contain - 20 bonate , 2 , 2 , 2 - trichloroethyl - 2 ' , 2 ' - dichloroethyl carbonate , ing organic solvent, an acyclic carbonate having a halogen bis (2 ,2 ,2 -trichloroethyl ) carbonate , atom , and an acyclic carbonate having no halogen atoms and fluoromethyl vinyl carbonate , 2 - fluoroethyl vinyl carbonate , the like . 2 ,2 -difluoroethyl vinyl carbonate , 2 ,2 , 2- trifluoroethyl vinyl < 1 - 2 - 2. Acyclic Carbonate > carbonate, chloromethyl vinyl carbonate , 2 - chloroethyl The acyclic carbonate to be used as the “ carbonate having 25 vinyl carbonate , 2 , 2 -dichloroethyl vinyl carbonate , 2 ,2 ,2 a halogen atom ” in invention 1 is explained below . The trichloroethyl vinyl carbonate , acyclic carbonate usually has two hydrocarbon groups, and fluoromethyl allyl carbonate , 2 - fluoroethyl allyl carbonate , these hydrocarbon groups may be the same or different. The 2 ,2 -difluoroethyl allyl carbonate , 2 ,2 , 2 - trifluoroethyl allyl number of carbon atoms of each of these hydrocarbon carbonate, chloromethyl allyl carbonate , 2 - chloroethyl allyl groups is preferably 1 or larger, and the upper limit thereof 30 carbonate , 2 , 2 - dichloroethyl allyl carbonate , 2 , 2 , 2 - trichloro is preferably 10 or smaller, especially preferably 6 or ethyl allyl carbonate , smaller . When the number thereof is outside the range , there fluoromethyl phenyl carbonate , 2 - fluoroethyl phenyl car are cases where this compound poses a problem concerning bonate , 2 ,2 - difluoroethyl phenyl carbonate , 2 ,2 ,2 -trifluoro the chemical stability and industrial availability thereof. ethyl phenyl carbonate , chloromethyl phenyl carbonate , Examples of the hydrocarbon groups constituting such an 35 2 - chloroethyl phenyl carbonate, 2 , 2 - dichloroethyl phenyl acyclic carbonate include ones which are the same as the carbonate, and 2 , 2 , 2 - trichloroethyl phenyl carbonate and the substituents with which the cyclic carbonate may be substi - like . tuted , and further include hydrocarbon groups which are the Preferred of these acyclic carbonates having a halogen same as the halogenated substituents. atom are the carbonates having a fluorine atom . In particular , Examples of the acyclic carbonate include 40 the following carbonates are more preferred from the stand dimethyl carbonate , diethyl carbonate , dipropyl carbonate , points of industrial availability and chemical stability : fluo dibutyl carbonate , divinyl carbonate , diallyl carbonate , romethyl methyl carbonate , bis ( fluoromethyl ) carbonate , diphenyl carbonate , ethyl methyl carbonate , methyl propy1 difluoromethyl methyl carbonate , 2 ,2 - difluoroethyl methyl carbonate , butylmethyl carbonate , methyl vinyl carbonate , carbonate , ethyl 2 , 2 - difluoroethyl carbonate , bis ( 2 , 2 - difluo allyl methyl carbonate , methyl phenyl carbonate , ethyl pro - 45 roethyl) carbonate , 2 , 2 , 2 -trifluoroethyl methyl carbonate , pyl carbonate , butyl ethyl carbonate , ethyl vinyl carbonate , ethyl 2 ,2 , 2 - trifluoroethyl carbonate , and bis ( 2 ,2 , 2 -trifluoro allyl ethyl carbonate , and ethyl phenyl carbonate and the ethyl) carbonate. like . The molecular weight of the acyclic carbonate having a Preferred of these from the standpoints of industrial halogen atom is not particularly limited , and may be any availability , etc . are dimethyl carbonate, diethyl carbonate , 50 value unless the effects of invention 1 are considerably diphenyl carbonate , ethyl methyl carbonate , methyl vinyl lessened thereby. However , the molecular weight thereof is carbonate , ethyl vinyl carbonate , allyl methyl carbonate, generally 50 or higher, preferably 80 or higher , and is allyl ethyl carbonate , methyl phenyl carbonate , ethyl phenyl generally 250 or lower, preferably 150 or lower. When the carbonate , and the like . acyclic carbonate has too high a molecular weight, this Examples of those acyclic carbonates which have been 55 acyclic carbonate having a halogen atom has reduced solu halogenated include bility in nonaqueous electrolyte 1 and there are cases where fluoromethyl methyl carbonate , difluoromethyl methyl car - it is difficult to sufficiently produce the effects of invention bonate , trifluoromethyl methyl carbonate , bis ( fluoromethyl) 1. carbonate , bis (difluoro )methyl carbonate , bis ( trifluoro ) m Processes for producing the acyclic carbonate having a ethyl carbonate , chloromethyl methyl carbonate , dichlorom - 60 halogen atom also are not particularly limited . The acyclic ethyl methyl carbonate , trichloromethyl methyl carbonate , carbonate can be produced by a known process selected at bis ( chloromethyl) carbonate , bis ( dichloro )methyl carbonate , will. bis ( trichloro )methyl carbonate , Any one of those acyclic carbonates having a halogen 2 - fluoroethyl methyl carbonate , ethyl fluoromethyl carbon atom explained above may be contained alone in nonaque ate , 2 , 2 -difluoroethyl methyl carbonate , 2 - fluoroethyl fluo - 65 ous electrolyte 1 of the invention , or any desired combina romethyl carbonate , ethyl difluoromethyl carbonate , 2 , 2 , 2 - tion of two or more of these may be contained in any desired trifluoroethyl methyl carbonate , 2 , 2 - difluoroethyl proportion . US 9 ,853 , 326 B2 19 20 It is thought that the acyclic carbonate having a halogen having a halogen atom , and an acyclic carbonate ; an acyclic atom performs different functions according to the content carbonate having a halogen atom , a cyclic carbonate having thereof. Factors in this have not been elucidated in detail. a halogen atom , and a cyclic carboxylic acid ester; an acyclic Although the scope of invention 1 should not be construed carbonate having a halogen atom , a cyclic carbonate having as being limited by the factors , the following is thought. In 5 a halogen atom , and a phosphorus -containing organic sol the case where the acyclic carbonate having a halogen atom vent; an acyclic carbonate having a halogen atom , a cyclic is used as an additive in an amount of from 0 . 001 % by mass carbonate having no halogen atoms, an acyclic carbonate , to 10 % by mass based on the whole nonaqueous solvent, this acyclic carbonate is thought to decompose on the surface of and a cyclic carboxylic acid ester ; the negative electrode to form a protective film for protect- 10 an acyclic carbonate having a halogen atom , a cyclic car ing the surface of the negative electrode . On the other hand , bonate having no halogen atoms, a cyclic carbonate having in the case where the acyclic carbonate having a halogen a halogen atom , and a cyclic carboxylic acid ester ; an acyclic atom is used as a nonaqueous solvent in an amount of from carbonate having a halogen atom , a cyclic carbonate having 10 % by mass to 100 % by mass, this acyclic carbonate is no halogen atoms, a phosphorus - containing organic solvent, thought to not only perform that function of an additive but 15 and a cyclic carboxylic acid ester ; an acyclic carbonate also perform the function of improving the oxidation resis having a halogen atom , a cyclic carbonate having no halogen tance of nonaqueous electrolyte 1 . atoms, a cyclic carboxylic acid ester, and an acyclic carbon In the case where the acyclic carbonate having a halogen ate having no halogen atoms; an acyclic carbonate having a atom is used as an additive , the content thereof is generally halogen atom , a cyclic carbonate having no halogen atoms, 0 .001 % by mass or higher, preferably 0 .01 % by mass or 20 a cyclic ether , and an acyclic carbonate having no halogen higher , and is generally 10 % by mass or lower , preferably atoms; an acyclic carbonate having a halogen atom , a cyclic 5 % by mass or lower , based on the whole nonaqueous carbonate having no halogen atoms, a phosphorus- contain solvent. When the content thereof is too low , there are cases ing organic solvent, and an acyclic carbonate having no where the formation of a negative - electrode coating film halogen atoms; based on the reductional decomposition of the acyclic car - 25 an acyclic carbonate having a halogen atom , a cyclic car bonate is insufficient, making it impossible to impart suffi - bonate having no halogen atoms, a cyclic carbonate having cient battery characteristics . a halogen atom , and an acyclic carbonate having no halogen In the case where the acyclic carbonate having a halogen atoms; an acyclic carbonate having a halogen atom , a cyclic atom is used as a nonaqueous solvent, the content thereof is carbonate having no halogen atoms, a cyclic carbonate generally 10 % by mass or higher, preferably 12 % by mass 30 having a halogen atom , and a cyclic carboxylic acid ester ; an or higher, most preferably 15 % by mass or higher , and is acyclic carbonate having a halogen atom , a cyclic carbonate generally 100 % by mass or lower, preferably 80 % by mass having no halogen atoms, a cyclic carbonate having a or lower, most preferably 50 % by mass or lower , based on halogen atom , a cyclic carboxylic acid ester, and an acyclic the whole nonaqueous solvent. When the content thereof is carbonate having no halogen atoms; an acyclic carbonate lower than the lower limit , there are cases where the 35 having a halogen atom , a cyclic carbonate having no halogen oxidative decomposition of other components of nonaque - atoms, a cyclic carbonate having a halogen atom , a cyclic ous electrolyte 1 which proceeds on the surface of the ether , and an acyclic carbonate having no halogen atoms; positive electrode is not inhibited to a desirable degree , and an acyclic carbonate having a halogen atom , a cyclic making it impossible to produce the effects of invention 1 . carbonate having no halogen atoms, a cyclic carbonate On the other hand , contents thereof higher than the upper 40 having a halogen atom , a phosphorus -containing organic limit result in an increased viscosity of the electrolyte and solvent, and an acyclic carbonate having no halogen atoms there are hence cases where the increased viscosity reduces and the like . various characteristics of the battery . < 1 - 3 . Nonaqueous Solvent Other than Carbonates Having The acyclic carbonate having a halogen atom may be used Halogen Atom > as a mixture with the cyclic carbonate having a halogen atom 45 The " nonaqueous solvent other than carbonates having a which was described above and /or the " nonaqueous solvent halogen atom ” which may be contained in nonaqueous other than the carbonates having a halogen atom ” which will electrolyte 1 of the invention is not particularly limited so be described later, in any desired proportion . Examples of long as it is a solvent which , after used to fabricate a battery , combinations in the case of employing such a mixture exerts no adverse influence on the battery characteristics . include : 50 However , this solvent preferably is one or more of the an acyclic carbonate having a halogen atom and a cyclic following “ nonaqueous solvents other than carbonates hav carbonate having no halogen atoms; an acyclic carbonate ing a halogen atom ” . having a halogen atom and a cyclic carbonate having a Examples of the “ nonaqueous solvent other than carbon halogen atom ; an acyclic carbonate having a halogen atom a tes having a halogen atom ” include acyclic or cyclic and a cyclic carboxylic acid ester; an acyclic carbonate 55 carbonates, acyclic or cyclic carboxylic acid esters , acyclic having a halogen atom and a phosphorus - containing organic or cyclic ethers , phosphorus -containing organic solvents , solvent ; and sulfur- containing organic solvents and the like. an acyclic carbonate having a halogen atom , a cyclic car - The acyclic carbonates also are not limited in the kind bonate having no halogen atoms, and an acyclic carbonate ; thereof . However, dialkyl carbonates are preferred . The an acyclic carbonate having a halogen atom , a cyclic car - 60 number of carbon atoms of each constituent alkyl group is bonate having no halogen atoms, and a cyclic carbonate preferably 1 -5 , especially preferably 1 - 4 . Examples thereof having a halogen atom ; an acyclic carbonate having a include halogen atom , a cyclic carbonate having no halogen atoms, dimethyl carbonate , ethylmethyl carbonate , diethyl carbon and a cyclic carboxylic acid ester ; an acyclic carbonate ate , methyl n - propyl carbonate, ethyl n -propyl carbonate , having a halogen atom , a cyclic carbonate having no halogen 65 and di- n -propyl carbonate and the like . atoms, and a phosphorus - containing organic solvent; an Of these , dimethyl carbonate , ethyl methyl carbonate , or acyclic carbonate having a halogen atom , a cyclic carbonate diethyl carbonate is preferred from the standpoint of indus US 9 ,853 , 326 B2 21 22 trial availability and because these compounds are satisfac - because these compounds are satisfactory in various prop tory in various properties in a nonaqueous - electrolyte sec erties in a nonaqueous -electrolyte secondary battery. More ondary battery. preferred of these is ethylene carbonate , propylene carbon The cyclic carbonates are not limited in the kind thereof. ate , dimethyl carbonate , ethyl methyl carbonate , diethyl However, the number of carbon atoms of the alkylene group 5 carbonate , ethyl acetate , methyl propionate , ethyl propi constituting each cyclic carbonate is preferably 2 - 6 , espe onate , or y -butyrolactone . Especially preferred is dimethyl cially preferably 2 - 4 . Examples of the cyclic carbonates carbonate , ethyl methyl carbonate, diethyl carbonate, ethyl include ethylene carbonate , propylene carbonate , and buty - acetate , methyl propionate , or ethyl propionate . lene carbonate (2 - ethylethylene carbonate or cis - or trans Those compounds may be used alone or in combination of 2 , 3 -dimethylethylene carbonate ) and the like . 10 two or more thereof. It is , however, preferred to use two or Of these , ethylene carbonate or propylene carbonate is more compounds in combination . For example , it is espe preferred because these compounds are satisfactory in vari cially preferred to use a high -permittivity solvent, such as a ous properties in a nonaqueous - electrolyte secondary bat - cyclic carbonate , in combination with a low - viscosity sol tery . vent, such as an acyclic carbonate or an acyclic ester and the The acyclic carboxylic acid esters also are not limited in 15 like . the kind thereof. Examples thereof include methyl acetate , A preferred combination of “ nonaqueous solvents other ethyl acetate , n - propyl acetate , isopropyl acetate , n -butyl than carbonates having a halogen atom ” is a combination acetate , isobutyl acetate , tert -butyl acetate , methyl propi consisting mainly of at least one of cyclic carbonates and at onate, ethyl propionate , n - propyl propionate , isopropyl pro least one of acyclic carbonates. In particular , the total pionate , n -butyl propionate , isobutyl propionate , and tert - 20 proportion of the cyclic carbonate and the acyclic carbonate butyl propionate and the like. to the whole nonaqueous solvent is generally 80 % by Of these , ethyl acetate , methyl propionate , or ethyl pro volume or higher, preferably 85 % by volume or higher, more pionate is preferred from the standpoint of industrial avail preferably 90 % by volume or higher. The proportion by ability and because these compounds are satisfactory in volume of the cyclic carbonate to the sum of the cyclic various properties in a nonaqueous -electrolyte secondary 25 carbonate and the acyclic carbonate is preferably 5 % by battery . volume or higher, more preferably 10 % by volume or higher, The cyclic carboxylic acid esters also are not limited in especially preferably 15 % by volume or higher , and is the kind thereof. Examples of such esters in ordinary use generally 50 % by volume or lower, preferably 35 % by include y - butyrolactone , y - valerolactone, and d - valerolac - volume or lower , more preferably 30 % by volume or lower. tone and the like . 30 Use of such combination of “ nonaqueous solvents other than Of these , y - butyrolactone is preferred from the standpoint carbonates having a halogen atom ” is preferred because the of industrial availability and because this compound is battery fabricated with this combination has an improved satisfactory in various properties in a nonaqueous -electro - balance between cycle characteristics and high - temperature lyte secondary battery . storability ( in particular, residual capacity and high - load The acyclic ethers also are not limited in the kind thereof. 35 discharge capacity after high - temperature storage ). Examples thereof include dimethoxymethane , dimethoxy - Examples of the preferred combination including at least ethane , diethoxymethane , diethoxyethane , one cyclic carbonate and at least one acyclic carbonate ethoxymethoxymethane , and ethoxymethoxyethane and the include: ethylene carbonate and dimethyl carbonate ; ethyl like . ene carbonate and diethyl carbonate ; ethylene carbonate and Of these, dimethoxyethane or diethoxyethane is preferred 40 ethyl methyl carbonate ; ethylene carbonate , dimethyl car from the standpoint of industrial availability and because bonate , and diethyl carbonate ; ethylene carbonate , dimethyl these compounds are satisfactory in various properties in a carbonate , and ethyl methyl carbonate ; ethylene carbonate , nonaqueous - electrolyte secondary battery . diethyl carbonate , and ethyl methyl carbonate ; and ethylene The cyclic ethers also are not limited in the kind thereof. carbonate , dimethyl carbonate , diethyl carbonate , and ethyl Examples of such ethers in ordinary use include tetrahydro - 45 methyl carbonate and the like . furan , 2 -methyltetrahydrofuran , and tetrahydropyran and the Combinations obtained by further adding propylene car like. bonate to those combinations including ethylene carbonate The phosphorus - containing organic solvents also are not and one or more acyclic carbonates are also included in particularly limited in the kind thereof. Examples thereof preferred combinations. In the case where propylene car include 50 bonate is contained , the volume ratio of the ethylene car phosphoric acid esters such as trimethyl phosphate , triethyl b onate to the propylene carbonate is preferably from 99 : 1 to phosphate , and triphenyl phosphate ; phosphorous acid esters 40 :60 , especially preferably from 95 : 5 to 50 :50 . It is also such as trimethyl phosphite , triethyl phosphite , and triphenyl preferred to regulate the proportion of the propylene car phosphite ; and phosphine oxides such as trimethylphosphine bonate to the whole nonaqueous solvent to a value which is oxide , triethylphosphine oxide, and triphenylphosphine 55 0 . 1 % by volume or higher, preferably 1 % by volume or oxide and the like . higher, more preferably 2 % by volume or higher , and is Furthermore , the sulfur - containing organic solvents also generally 10 % by volume or lower, preferably 8 % by are not particularly limited in the kind thereof. Examples volume or lower, more preferably 5 % by volume or lower . thereof include This is because this regulation brings about excellent dis ethylene sulfite , 1 , 3 - propanesultone, 1 , 4 -butanesultone , 60 charge load characteristics while maintaining the properties methyl methanesulfonate, busulfan , sulfolane, sulfolene , of the combination of ethylene carbonate and one or more dimethyl sulfone , diphenyl sulfone , methyl phenyl sulfone , acyclic carbonates. dibutyl disulfide, dicyclohexyl disulfide, tetramethylthiuram More preferred of these are combinations including an monosulfide , N , N -dimethylmethanesulfonamide , and N , N - asymmetric acyclic carbonate . In particular, combinations diethylmethanesulfonamide and the like . 65 including ethylene carbonate , a symmetric acyclic carbon Of those compounds, the acyclic or cyclic carbonates or a te , and an asymmetric acyclic carbonate , such as a combi the acyclic or cyclic carboxylic acid esters are preferred nation of ethylene carbonate , dimethyl carbonate , and ethyl US 9 ,853 , 326 B2 23 24 methyl carbonate , a combination of ethylene carbonate , metal” ) or with a quaternary onium . The monofluorophos diethyl carbonate , and ethyl methyl carbonate , and a com phate and / or difluorophosphate may be one salt or may be bination of ethylene carbonate , dimethyl carbonate , diethyl carbonate , and ethyl methyl carbonate , or such combinations < 1 - 3 -1 .Monofluorophosphoric Acid Metal Salt and Difluo which further contain propylene carbonate are preferred 5 rophosphoric Acid Metal Salt > because these combinations have a satisfactory balance First, an explanation is given on the case where the between cycle characteristics and discharge load character monofluorophosphate and difluorophosphate in the inven istics . Preferred of such combinations are ones in which the tion are a salt of one or more monofluorophosphate ions or asymmetric acyclic carbonate is ethyl methyl carbonate . one or more difluorophosphate ions with one or more specific -metal ions (hereinafter sometimes referred to as Furthermore , the number of carbon atoms of each of the 10 “ monofluorophosphoric acid metal salt ” and “ difluorophos alkyl groups constituting each dialkyl carbonate is prefer phoric acid metal salt ” , respectively ) . ably 1 - 2 . Examples of the metals in Group 1 of the periodic table Other examples of preferred mixed solvents are ones among the specific metals usable in the monofluorophos containing an acyclic ester. In particular, the cyclic carbon phoric acid metal salt and difluorophosphoric acid metal salt ate /acyclic carbonate mixed solvents which contain an acy - 15 in the invention include lithium , sodium , potassium , and clic ester are preferred from the standpoint of improving the cesium . Preferred of these is lithium or sodium . Lithium is low - temperature characteristics of a battery . The acyclic especially preferred . ester especially preferably is ethyl acetate or methyl propi Examples of the metals in Group 2 of the periodic table onate. The proportion by volume of the acyclic ester to the include magnesium , calcium , strontium , and barium . Pre whole nonaqueous solvent is generally 5 % or higher, pref - 20 ferred of these is magnesium or calcium . Magnesium is erably 8 % or higher, more preferably 15 % or higher, and is especially preferred . generally 50 % or lower, preferably 35 % or lower, more Examples of the metals in Group 13 of the periodic table preferably 30 % or lower , even more preferably 25 % or include aluminum , gallium , indium , and thallium . Preferred lower. of these is aluminum or gallium . Aluminum is especially Other preferred examples of the “ nonaqueous solvent 25 preferred . other than carbonates having a halogen atom ” are ones in The number of the atoms of such a specific metal pos which one organic solvent selected from the group consist - sessed by one molecule of the monofluorophosphoric acid ing of ethylene carbonate, propylene carbonate , butylene metal salt or difluorophosphoric acid metal salt in the carbonate , y - butyrolactone , and y - valerolactone or a mixed invention is not limited . The salt may have only one atom of solvent composed of two or more organic solvents selected 30 the specific metal or two or more atoms thereof. from the group accounts for at least 60 % by volume of the In the case where the monofluorophosphoric acid metal whole . Such mixed solvents have a flash point of preferably salt or the difluorophosphoric acid metal salt in the invention 50° C . or higher, especially preferably 70° C . or higher. has two or more specific -metal atoms per molecule , these Nonaqueous electrolyte 1 employing this solvent is reduced specific -metal atoms may be of the same kind or may be of in solvent vaporization and liquid leakage even when used 35 different kinds . Besides the specific metal( s ), one or more at high temperatures. In particular, when such a nonaqueous atoms of a metal other than the specific metals may be solvent which includes ethylene carbonate and y -butyrolac posspossessed . tone in a total amount of 80 % by volume or larger, prefer Examples of the monofluorophosphoric acid metal salt ably 90 % by volume or larger , based on the whole nonaque and difluorophosphoric acid metal salt include Li PO3F, ous solvent and in which the volume ratio of the ethylene 40 Na2PO3F , MgPO3F , CaPO3F , Al2 ( PO3F ) 3 , Ga , ( PO3F ) 3 , carbonate to the y- butyrolactone is from 5: 95 to 45 :55 or LiPO F2, NaPO ,F2 , Mg( PO ,F2 ) 2, Ca (PO , F2) 2, Al( PO _ F2) 3 , such a nonaqueous solvent which includes ethylene carbon - and Ga (PO2F2 ) 3 . Preferred of these are Li2POZF , LiPO , F ) , ate and propylene carbonate in a total amount of 80 % by NaPO , F2, and Mg( PO ,F2 ) 2 and the like. volume or larger , preferably 90 % by volume or larger , based < 1 - 3 - 2 . Monofluorophosphoric Acid Quaternary Onium Salt on the whole nonaqueous solvent and in which the volume 45 and Difluorophosphoric Acid Quaternary Onium Salt > ratio of the ethylene carbonate to the propylene carbonate is An explanation is then given on the case where the from 30 :70 to 80 : 20 is used , then an improved balance monofluorophosphatemonofluorophosphate and difluorophosphate in invention 1 between cycle characteristics and discharge load character to invention 6 are a salt of a monofluorophosphate ion or istics , etc . is generally obtained . difluorophosphate ion with a quaternary onium (hereinafter < 1 - 3 . Monofluorophosphate and Difluorophosphate > 50 sometimes referred to as “ monofluorophosphoric acid qua Nonaqueous electrolyte 1 of the invention contains a ternary onium salt” and “ difluorophosphoric acid quaternary monofluorophosphate and /or a difluorophosphate as an o nium salt ” , respectively ) . essential component. The “ monofluorophosphate and /or dif - The quaternary onium used in the monofluorophosphoric luorophosphate” to be used in the invention is not particu - acid quaternaryonium salt and difluorophosphoric acid larly limited in the kind thereof so long as this ingredient is 55 quaternary onium salt in invention 1 to invention 6 usually constituted of one or more monofluorophosphate ions and / or is a cation . Examples thereof include cations represented by difluorophosphate ions and one or more cations. However , the following general formula (1 ). this ingredient must be selected in view of the necessity of finally producing a nonaqueous electrolyte usable as the electrolyte of a nonaqueous -electrolyte secondary battery to 60 [Chemical Formula- 3 ] be used . (1 ) It is therefore preferred that the monofluorophosphate R ! and /or difluorophosphate in the invention should be a salt of one or more monofluorophosphate ions and / or difluorophos R2 - 07 - R3 phate ions with one or more ions of at least one metal 65 selected from Group 1 , Group 2 , and Group 13 of the periodic table (hereinafter suitably referred to as “ specific US 9 ,853 , 326 B2 25 26 In general formula ( 1 ), Rl to R4 each independently resented by each of Rl to R has substituents , the number of represent a hydrocarbon group . The kind of this hydrocarbon carbon atoms of the substituted hydrocarbon group includ group is not limited . Namely , the hydrocarbon group may be ing these substituents is generally within that range . an aliphatic hydrocarbon group or an aromatic hydrocarbon In general formula ( 1 ) , Q represents an atom belonging to group , or may be a hydrocarbon group including these two 5 Group 15 of the periodic table . Preferred of such atoms is a kinds of groupss bonded to eacheach otherother. In the case ofof anan nitrogen atom or phosphorus atom . aliphatic hydrocarbon group , this group may be an acyclic or In view of the above explanation , preferred examples of cyclic group or may be a structure including an acyclic the quaternary onium represented by general formula ( 1 ) moiety and a cyclic moiety bonded thereto . In the case of an include aliphatic acyclic quaternary salts , alicyclic ammo acyclic hydrocarbon group , this group may be linear or 10 niumsn , alicyclic phosphoniums, and nitrogen - containing branched . The hydrocarbon group may be a saturated hydro heter carbon group or may have an unsaturated bond . heterocyclic aromatic cations . Examples of the hydrocarbon groups represented by Rito Especially preferred of the aliphatic acyclic quaternary R4 include alkyl groups, cycloalkyl groups, aryl groups, and salts are tetraalkylammoniums, tetraalkylphosphoniums, aralkyl groups , and the like . s and the like . Examples of the alkyl groups include Examples of the tetraalkylammoniums include methyl, ethyl, 1 -propyl , 1- methylethyl , 1 -butyl , 1 -methyl - tetramethylammonium , ethyltrimethylammonium , diethyl propyl, 2 -methylpropyl , and 1, 1 - dimethylethyl . dimethylammonium , triethylmethylammonium , tetraethyl Preferred of these are methyl , ethyl, 1 -propyl , 1 -butyl , and ammonium , and tetra - n -butylammonium , and the like . the like . 20 Examples of the tetraalkylphosphoniums include Examples of the cycloalkyl groups include tetramethylphosphonium , ethyltrimethylphosphonium , cyclopentyl , 2 -methylcyclopentyl , 3 -methylcyclopentyl , diethyldimethylphosphonium , triethylmethylphosphonium , 2 ,2 -dimethylcyclopentyl , 2 ,3 -dimethylcyclopentyl , 2 ,4 -dim tetraethylphosphonium , and tetra -n -butylphosphonium , and ethylcyclopentyl , 2 , 5 - dimethylcyclopentyl , 3 , 3 - dimethylcy - the like . clopentyl, 3 ,4 -dimethylcyclopentyl , 2 -ethylcyclopentyl , 25 Especially preferred of the alicyclic ammoniums are 3 -ethylcyclopentyl , cyclohexyl, 2 -methylcyclohexyl , pyrrolidiniums, morpholiniums, imidazoliniums, tetrahy 3 -methylcyclohexyl , 4 -methylcyclohexyl , 2 ,2 -dimethylcy dropyrimidiniums, piperaziniums, piperidiniums, and the clohexyl, 2 ,3 - dimethylcyclohexyl, 2 ,4 - dimethylcyclohexyl, 2 ,5 -dimethylcyclohexyl , 2 ,6 -dimethylcyclohexyl , 3 ,4 -dim like. ethylcyclohexyl, 3 , 5 - dimethylcyclohexyl, 2 - ethylcyclo - 30 N Examples of the pyrrolidiniums include hexyl, 3 - ethylcyclohexyl, 4 - ethylcyclohexyl, bicyclo [ 3 .610 2 . 1 ] 30 N , N - dimethylpyrrolidium , N - ethyl- N -methylpyrrolidium , oct - 1 - yl, and bicyclo [ 3 . 2 . 1 ] oct - 2 - yl, and the like . and N , N - diethylpyrrolidium , and the like . Preferred of these are cyclopentyl, 2 -methylcyclopentyl , Examples of the morpholiniums include 3 -methylcyclopentyl , cyclohexyl , 2 -methylcyclohexyl , N , N - dimethylmorpholinium , N - ethyl- N -methylmorpho 3 -methylcyclohexyl , 4 -methylcyclohexyl , and the like. " 35 linium , and N , N - diethylmorpholinium , and the like . Examples of the aryl groups include Examples of the imidazoliniums include phenyl, 2 -methylphenyl , 3 -methylphenyl hylphenyl , 4 -methylphenyl , N , N - dimethylimidazolinium , N -ethyl - N ' -methylimidazo and 2 , 3 - dimethylphenyl, and the like . linium , N , N - diethylimidazolinium , and 1 , 2 , 3 - trimethylimi Preferred of these is phenyl. dazolinium , and the like . Examples of the aralkyl groups include 40 Examples of the tetrahydropyrimidiniums include phenylmethyl, 1 -phenylethyl , 2 -phenylethyl , diphenylm - N , N -dimethyltetrahydropyrimidinium , N - ethyl- N '- methyl ethyl, and triphenylmethyl and the like . tetrahydropyrimidinium , N , N - diethyltetrahydropyrimi Preferred of these are phenylmethyl and 2 -phenylethyl . dinium , and 1 , 2, 3 -trimethyltetrahydropyrimidinium , and the The hydrocarbon groups represented by Rl to R4 each like . may be substituted with one ormore substituents . The kinds 45 Examples of the piperaziniums include of the substituents are not limited unless the substituents N , N , N ', N '- tetramethylpiperazinium , N - ethyl- N , N ', N ' - trim considerably lessen the effects of invention 1 . Examples of ethylpiperazinium , N , N - diethyl- N ' , N - dimethylpiper the substituents include halogen atoms, hydroxyl, amino , azinium , N , N , N '- triethyl- N -methylpiperazinium , and N ,N , nitro , cyano , carboxyl, ether groups, and aldehyde groups. In N ', N '- tetraethylpiperazinium , and the like . the case where the hydrocarbon group represented by each 50 Examples of the piperidiniums include of R1 to R4 has two or more substituents, these substituents N , N - dimethylpiperidinium , N - ethyl- N -methylpiperidinium , may be the same or different. and N ,N -diethylpiperidinium , and the like. When any two or more of the hydrocarbon groups rep - Especially preferred of the nitrogen - containing heterocy resented by Rl to R * are compared , the hydrocarbon groups clic aromatic cations are pyridiniums, imidazoliums, and the may be the same or different. When the hydrocarbon groups 55 like . represented by R to Rº have a substituent, these substituted Examples of the pyridiniums include hydrocarbon groups including the substituents may be the N -methylpyridinium , N - ethylpyridinium , 1 ,2 -dimethylpy same or different. Furthermore, any desired two or more of rimidinium , 1 ,3 -dimethylpyrimidinium , 1 ,4 -dimethylpy the hydrocarbon groups represented by Rl to R4 may be rimidinium , and l- ethyl- 2 -methylpyrimidinium , and the bonded to each other to form a cyclic structure . 60 like . The number of carbon atoms of each of the hydrocarbon Examples of the imidazoliums include groups represented by Rd to R4 is generally 1 or larger, and N , N - dimethylimidazolium , N - ethyl- N -methylimidazolium , the upper limit thereof is generally 20 or smaller , preferably N , N -diethylimidazolium , and 1, 2 ,3 - trimethylimidazolium 10 or smaller , more preferably 5 or smaller. When the and the like . number of carbon atoms thereof is too large, the number of 65 Namely , the salts of the quaternary oniums enumerated moles per unit mass is too small and various effects tend to above with the monofluorophosphate ions and /or difluoro be reduced . In the case where the hydrocarbon group rep phosphate ions enumerated above are preferred examples of US 9 ,853 , 326 B2 27 28 the monofluorophosphoric acid quaternary onium salt and and discharging the nonaqueous electrolyte therefrom does difluorophosphoric acid quaternary onium salt in the inven not contain the monofluorophosphate and / or difluorophos tion . phate , then there are often cases where the phosphoric acid < 1 - 3 - 3 . Content, Detection (Derivation of Containment) , salt is detected on the positive electrode, negative electrode , Technical Range , etc . > 5 or separator as another constituent member of the nonaque In the nonaqueous electrolyte of the invention , one mono - ous -electrolyte secondary battery . Consequently , when at fluorophosphate or difluorophosphate only may be used or least one monofluorophosphate and / or difluorophosphate any desired combination of two or more monofluorophos- has been detected in at least one constituent member phates and / or difluorophosphates may be used in any desired selected from the positive electrode , negative electrode , and proportion . However, from the standpoint of efficiently 10 separator , this case also is regarded as included in the operating the nonaqueous -electrolyte secondary battery , it is invention . preferred to use one monofluorophosphate or difluorophos - Moreover, when a monofluorophosphate and / or a difluo phate . rophosphate has been incorporated into a nonaqueous elec The molecular weight of the monofluorophosphate or trolyte and has further been incorporated into at least one difluorophosphate is not limited , and may be any desired 15 constituted member selected from the positive electrode , value unless this considerably lessens the effects of the negative electrode , and separator, this case also is regarded invention . However , the molecular weight thereof is gener - as included in the invention . ally 100 or higher. There is no particular upper limit on the On the other hand , a monofluorophosphate and /or a molecular weight thereof. However , it is preferred that the difluorophosphate may be incorporated beforehand into an molecular weight thereof should be generally 1, 000 or 20 inner part or the surface of the positive electrode of a lower, preferably 500 or lower, because such a value is nonaqueous -electrolyte secondary battery to be fabricated . practicable in view of the reactivity of this reaction . In this case , part or the whole of the monofluorophosphate Usually , one salt of monofluorophosphoric acid or one salt and /or difluorophosphate which has been incorporated of difluorophosphoric acid is used . However, in the case beforehand is expected to dissolve in the nonaqueous elec where it is preferred to use a mixture of two or more salts in 25 trolyte to perform the function thereof. This case also is the nonaqueous electrolyte to be prepared , a mixture of two regarded as included in the invention . or more of monofluorophosphates and difluorophosphates Techniques for incorporating the salt beforehand into an may be used . 11inner part of a positive electrode or into the surface of a The molecular weight of the monofluorophosphate or positive electrode are not particularly limited . Examples difluorophosphate is not limited , and may be any desired 30 thereof include : a method in which a monofluorophosphate value unless this considerably lessens the effects of the and / or a difluorophosphate is dissolved beforehand in a invention . However , the molecular weight thereof is gener - slurry to be prepared in the production of a positive electrode ally 150 or higher . There is no particular upper limit on the which will be described later ; and a method in which a molecular weight thereof. However, it is preferred that the solution prepared by dissolving a monofluorophosphate and / molecular weight thereof should be generally 1 ,000 or 35 or a difluorophosphate in any desired nonaqueous solvent lower, preferably 500 or lower , because such a value is beforehand is applied to or infiltrated into a positive elec practicable in view of the reactivity of this reaction . trode which has been produced , and this electrode is dried to The proportion of the monofluorophosphate and difluo - remove the solvent used and thereby incorporate the salt . rophosphate in the nonaqueous electrolyte is preferably 10 Furthermore , use may be made of a method in which a ppm or higher (0 .001 % by mass or higher ), more preferably 40 nonaqueous -electrolyte secondary battery is actually fabri 0 .01 % by mass or higher, especially preferably 0 .05 % by cated using a nonaqueous electrolyte containing at least one mass or higher , even more preferably 0 . 1 % by mass or monofluorophosphate and /or difluorophosphate so that the higher, in terms of the total content of the salts based on the salt is incorporated into an inner part of the positive elec whole nonaqueous electrolyte . The upper limit of the pro trode or the surface of the positive electrode from the portion of the sum of the salts is preferably 5 % by mass or 45 nonaqueous electrolyte . Since the nonaqueous electrolyte is lower, more preferably 4 % by mass or lower , even more infiltrated into the positive electrode in fabricated a non preferably 3 % by mass or lower . When the concentration of aqueous -electrolyte secondary battery , there are often cases the monofluorophosphate and the difluorophosphate is tootoo where the monofluorophosphate and difluorophosphate are low , there are cases where the effect of improving discharge contained in an inner part of the positive electrode or in the load characteristics is difficult to obtain . On the other hand , 50 surface of the positive electrode. Because of this , when at too high concentrations thereof may lead to a decrease in least a monofluorophosphate and /or a difluorophosphate can charge/ discharge efficiency. be detected in the positive electrode recovered from a When a nonaqueous electrolyte containing a monofluo - disassembled battery , this case is regarded as included in the rophosphate and a difluorophosphate is subjected to the invention . actual fabrication of a nonaqueous - electrolyte secondary 55 A monofluorophosphate and a difluorophosphate may be battery and the battery is disassembled to discharge the incorporated beforehand into an inner part or the surface of nonaqueous electrolyte again , then there are often cases the negative electrode of a nonaqueous - electrolyte second where the content of the salts in this nonaqueous electrolyte a ry battery to be fabricated . In this case , part or the whole of has decreased considerably . Consequently , the nonaqueous the monofluorophosphate and/ or difluorophosphate which electrolyte discharged from a battery can be regarded as 60 has been incorporated beforehand is expected to dissolve in included in the invention when at least one monofluoro - the nonaqueous electrolyte to perform the function thereof. phosphate and /or difluorophosphate can be detected in the This case is regarded as included in the invention . Tech electrolyte even in a slight amount. Furthermore , even when niques for incorporating the salt beforehand into an inner a nonaqueous electrolyte containing a monofluorophosphate part of a negative electrode or into the surface of a negative and a difluorophosphate is subjected to the actual fabrication 65 electrode are not particularly limited . Examples thereof of a nonaqueous - electrolyte secondary battery and the non - include : a method in which a monofluorophosphate and a aqueous electrolyte recovered by disassembling this battery difluorophosphate are dissolved beforehand in a slurry to be US 9 ,853 , 326 B2 29 30 prepared in the production of a negative electrode which will contained therein to thereby form a satisfactory protective be described later ; and a method in which a solution pre coating layer on the surface of the negative - electrode active pared by dissolving a monofluorophosphate and a difluoro material, and this protective coating layer is thought to phosphate in any desired nonaqueous solvent beforehand is inhibit side reactions to inhibit the deterioration caused by applied to or infiltrated into a negative electrode which has 5 high - temperature storage . It is also thought that the coexis been produced , and this electrode is dried to remove the tence of the monofluorophosphate and / or difluorophosphate solvent used and thereby incorporate the salt . and the carbonate having a halogen atom in the electrolyte Furthermore , use may be made of a method in which a contributes to an improvement in the properties of the nonaqueous -electrolyte secondary battery is actually fabri- protective coating film in some way . cated using a nonaqueous electrolyte containing at least one 10 < 1 - 4 . Additives > monofluorophosphate and difluorophosphate so that the salt The nonaqueous electrolyte of invention 1 may contain is incorporated into an inner part of the negative electrode or various additives so long as these additives do not consid the surface of the negative electrode from the nonaqueous erably lessen the effects of invention 1 . In the case where electrolyte . Since the nonaqueous electrolyte is infiltrated additives are additionally incorporated to prepare the non into the negative electrode in fabricated a nonaqueous - 15 aqueous electrolyte , conventionally known additives can be electrolyte secondary battery , there are often cases where the used at will . One additive may be used alone, or any desired monofluorophosphate and difluorophosphate are contained combination of two or more additives may be used in any in an inner part of the negative electrode or in the surface of desired proportion . the negative electrode . Because of this , when at least a Examples of the additives include overcharge inhibitors monofluorophosphate and a difluorophosphate can be 20 and aids for improving capacity retentivity and cycle char detected in the negative electrode recovered from a disas acteristics after high -temperature storage . It is preferred to sembled battery , this case is regarded as included in the add a carbonate having an unsaturated bond (hereinafter invention . sometimes referred to as “ specific carbonate ” ) as an aid for A monofluorophosphate and / or a difluorophosphate may improving capacity retentivity and cycle characteristics after also be incorporated beforehand into an inner part or the 25 high - temperature storage , among those additives . The spe surface of the separator of a nonaqueous - electrolyte second cific carbonate and other additives are separately explained ary battery to be fabricated . In this case , part or the whole of below . the monofluorophosphate and difluorophosphate which have < 1 - 4 - 1 . Specific Carbonate > been incorporated beforehand is expected to dissolve in the The specific carbonate is a carbonate having an unsatu nonaqueous electrolyte to perform the function thereof. This 30 rated bond . The specific carbonate may have a halogen atom . case is regarded as included in the invention . Techniques for The molecular weight of the specific carbonate is not incorporating the salts beforehand into an inner part of a particularly limited , and may be any desired value unless separator or into the surface of a separator are not particu - this considerably lessens the effects of invention 1 . How larly limited . Examples thereof include : a method in which ever , themolecular weight thereof is generally 50 or higher, a monofluorophosphate and a difluorophosphate are mixed 35 preferably 80 or higher , and is generally 250 or lower , beforehand during separator production ; and a method in preferably 150 or lower. When the molecular weight thereof which a solution prepared by dissolving a monofluorophos is too high , this specific carbonate has reduced solubility in phate and a difluorophosphate in any desired nonaqueous the nonaqueous electrolyte and there are cases where the solvent beforehand is applied to or infiltrated into a separator effect of the carbonate is difficult to produce sufficiently. to be subjected to the fabrication of a nonaqueous - electro - 40 Processes for producing the specific carbonate also are not lyte secondary battery , and this separator is dried to remove particularly limited , and a known process selected at will can the solvent used and thereby incorporate the salt. be used to produce the carbonate . Furthermore , use may be made of a method in which a Any one specific carbonate may be incorporated alone nonaqueous - electrolyte secondary battery is actually fabri- into the nonaqueous electrolyte of invention 1 , or any cated using a nonaqueous electrolyte containing a mono - 45 desired combination of two or more specific carbonates may fluorophosphate and / or a difluorophosphate so that the salt is be incorporated thereinto in any desired proportion . incorporated into an inner part of the separator or the surface The amount of the specific carbonate to be incorporated of the separator from the nonaqueous electrolyte . Since the into the nonaqueous electrolyte of invention 1 is not limited , nonaqueous electrolyte is infiltrated into the separator in and may be any desired value unless this considerably fabricated a nonaqueous -electrolyte secondary battery , there 50 lessens the effects of invention 1 . It is , however , desirable are often cases where the monofluorophosphate and difluo - that the specific carbonate should be incorporated in a rophosphate are contained in an inner part of the separator concentration which is generally 0 .01 % by mass or higher, or in the surface of the separator. Because of this , when at preferably 0 . 1 % by mass or higher, more preferably 0 . 3 % by least a monofluorophosphate and a difluorophosphate can be mass or higher, and is generally 70 % by mass or lower, detected in the separator recovered from a disassembled 55 preferably 50 % by mass or lower, more preferably 40 % by battery , this case is regarded as included in the invention . mass or lower, based on the nonaqueous electrolyte of It is thought that when the monofluorophosphate and invention 1 . difluorophosphate are incorporated into a nonaqueous elec - When the amount of the specific carbonate is below the trolyte together with a carbonate having a halogen atom , this lower limit of that range, there are cases where use of this nonaqueous electrolyte can improve the high - temperature 60 nonaqueous electrolyte of invention 1 in a nonaqueous storability of a nonaqueous - electrolyte secondary battery electrolyte secondary battery results in difficulties in pro employing the nonaqueous electrolyte . Factors in this have ducing the effect of sufficiently improving the cycle char not been elucidated in detail . Although the scope of the acteristics of the nonaqueous - electrolyte secondary battery . invention is not construed as being limited by the factors , the On the other hand , when the proportion of the specific following is thought. The monofluorophosphate and / or dif - 65 carbonate is too high , there is a tendency that use of this luorophosphate contained in the nonaqueous electrolyte is nonaqueous electrolyte of invention 1 in a nonaqueous thought to react with the carbonate having a halogen atom electrolyte secondary battery results in decreases in the US 9 , 853, 326 B2 31 32 high - temperature storability and continuous -charge charac aromatic compounds having an oxygen atom , such as diphe teristics of the nonaqueous - electrolyte secondary battery . In nyl ether and dibenzofuran , and the like . particular, there are cases where gas evolution is enhanced Other examples of the overcharge inhibitors include prod and capacity retentivity decreases . ucts of the partial fluorination of aromatic compounds The specific carbonate according to invention 1 is not 5 shown above , such as fluorobenzene, fluorotoluene , benzo trifluoride, 2 - fluorobiphenyl, 0 - cyclohexylfluorobenzene , limited so long as it is a carbonate having one or more and p - cyclohexylfluorobenzene; and fluorine - containing carbon - carbon unsaturated bonds, e . g . , carbon - carbon anisole compounds such as 2 ,4 - difluoroanisole , 2 , 5 -difluo double bonds or carbon -carbon triple bonds. Any desired roanisole , and 1 , 6 - difluoroanisole , and the like . unsaturated carbonates may be used . Incidentally , carbon 10 One of those overcharge inhibitors may be used alone, or ates having one or more aromatic rings are included in the any desired combination of two or more thereofmay be used carbonate having an unsaturated bond . in any desired proportion . In the case of employing any Examples of the unsaturated carbonate include vinylene desired combination , compounds in the same class among carbonate and derivatives thereof, ethylene carbonate those enumerated above may be used in combination or derivatives substituted with one or more aromatic rings or 15 compounds in different classes may be used in combination . with one or more substituents having a carbon -carbon Examples of the case where compounds in different unsaturated bond , phenyl carbonates, vinyl carbonates, and classes are used in combination include allyl carbonates, and the like . a toluene derivative and a biphenyl derivative ; a toluene Examples of the vinylene carbonate and derivatives derivative and a terphenyl derivative ; a toluene derivative thereof include vinylene carbonate , methylvinylene carbon - 20 and a partly hydrogenated terphenyl derivative ; a toluene ate , 4 ,5 -dimethylvinylene carbonate , phenylvinylene car derivative and a cycloalkylbenzene derivative ; a toluene bonate , 4 , 5 - diphenylvinylene carbonate , and catechol car - derivative and an alkylbenzene derivative having one or bonate , and the like. more tertiary carbon atoms directly bonded to the benzene Examples of the ethylene carbonate derivatives substi - ring; a toluene derivative and an alkylbenzene derivative tuted with one or more aromatic rings or with one or more 25 having a quaternary carbon atom directly bonded to the substituents having a carbon -carbon unsaturated bond benzene ring ; a toluene derivative and an aromatic com include vinylethylene carbonate , 4 , 5 -divinylethylene car pound having an oxygen atom ; a toluene derivative and a bonate , phenylethylene carbonate , and 4 , 5 - diphenylethylene partly fluorinated aromatic compound ; a toluene derivative carbonate , and the like . and a fluorine- containing anisole compound; a biphenyl Examples of the phenyl carbonates include diphenyl 30 derivative and a terphenyl derivative ; a biphenyl derivative carbonate , ethyl phenyl carbonate , methyl phenyl carbonate , and a partly hydrogenated terphenyl derivative ; a biphenyl and t- butyl phenyl carbonate , and the like . derivative and a cycloalkylbenzene derivative ; a biphenyl Examples of the vinyl carbonates include divinyl carbon derivative and an alkylbenzene derivative having one or ate and methyl vinyl carbonate , and the like . more tertiary carbon atoms directly bonded to the benzene Examples of the allyl carbonates include diallyl carbonate 35 ring ; a biphenyl derivative and an alkylbenzene derivative and allyl methyl carbonate . having a quaternary carbon atom directly bonded to the Preferred of these specific carbonates are the vinylene benzene ring ; a biphenyl derivative and an aromatic com carbonate and derivatives thereof and the ethylene deriva - pound having an oxygen atom ; a biphenyl derivative and a tives substituted with one or more aromatic rings or with one partly fluorinated aromatic compound ; a biphenyl derivative or more substituents having a carbon - carbon unsaturated 40 and a fluorine - containing anisole compound ; a terphenyl bond . In particular , vinylene carbonate , 4 , 5 - diphenylvi- derivative and a partly hydrogenated terphenyl derivative ; a nylene carbonate , 4 , 5 - dimethylvinylene carbonate , and terphenyl derivative and a cycloalkylbenzene derivative ; a vinylethylene carbonate are more preferred because these terphenyl derivative and an alkylbenzene derivative having carbonates form a stable interface - protective coating film . one or more tertiary carbon atoms directly bonded to the < 1 - 4 - 2 . Other Additives 45 benzene ring ; a terphenyl derivative and an alkylbenzene Additives other than the specific carbonate are explained derivative having a quaternary carbon atom directly bonded below . Examples of the additives other than the specific to the benzene ring; a terphenyl derivative and an aromatic carbonate include overcharge inhibitors and aids for improv compound having an oxygen atom ; a terphenyl derivative ing capacity retentivity and cycle characteristics after high - and a partly fluorinated aromatic compound ; a terphenyl temperature storage . 50 derivative and a fluorine - containing anisole compound ; a < 1 - 4 - 2 - 1 . Overcharge Inhibitors > partly hydrogenated terphenyl derivative and a cycloalkyl Examples of the overcharge inhibitors include aromatic benzene derivative; a partly hydrogenated terphenyl deriva compounds including : toluene derivatives thereof, such as tive and an alkylbenzene derivative having one or more toluene and xylene ; unsubstituted biphenyl or alkyl- substi - tertiary carbon atoms directly bonded to the benzene ring ; a tuted biphenyl derivatives, such as biphenyl, 2 -methylbiphe - 55 partly hydrogenated terphenyl derivative and an alkylben nyl, 3 -methylbiphenyl , and 4 -methylbiphenyl ; unsubstituted zene derivative having a quaternary carbon atom directly terphenyls or alkyl -substituted terphenyl derivatives , such as bonded to the benzene ring ; a partly hydrogenated terphenyl 0 - terphenyl, m - terphenyl, and p -terphenyl ; partly hydroge - derivative and an aromatic compound having an oxygen nated unsubstituted terphenyls or partly hydrogenated alkyl - atom ; a partly hydrogenated terphenyl derivative and a substituted terphenyl derivatives , cycloalkylbenzenes and 60 partly fluorinated aromatic compound ; a partly hydroge derivatives thereof, such as cyclopentylbenzene and cyclo - nated terphenyl derivative and a fluorine - containing anisole hexylbenzene ; alkylbenzene derivatives having one or more compound ; a cycloalkylbenzene derivative and an alkylben tertiary carbon atoms directly bonded to the benzene ring, zene derivative having one or more tertiary carbon atoms such as cumene, 1 , 3 - diisopropylbenzene , and 1 , 4 - diisopro - directly bonded to the benzene ring ; a cycloalkylbenzene pylbenzene; alkylbenzene derivatives having a quaternary 65 derivative and an alkylbenzene derivative having a quater carbon atom directly bonded to the benzene ring , such as nary carbon atom directly bonded to the benzene ring ; a t - butylbenzene , t - amylbenzene , and t- hexylbenzene ; and cycloalkylbenzene derivative and an aromatic compound US 9 ,853 , 326 B2 33 34 having an oxygen atom ; a cycloalkylbenzene derivative and benzene , a combination of m - terphenyl and a partly fluorinated aromatic compound ; a cycloalkylben - p - fluorocyclohexylbenzene , a combination of m - terphenyl zene derivative and a fluorine - containing anisole compound ; and 2 ,4 -difluoroanisole , an alkylbenzene derivative having one or more tertiary a combination of a partly hydrogenated terphenyl derivative carbon atoms directly bonded to the benzene ring and an 5 and cumene, a combination of a partly hydrogenated ter alkylbenzene derivative having a quaternary carbon atom phenyl derivative and cyclopentylbenzene, a combination of directly bonded to the benzene ring; an alkylbenzene deriva tive having one or more tertiary carbon atoms directly a partly hydrogenated terphenyl derivative and cyclohexyl bonded to the benzene ring and an aromatic compound benzene, a combination of a partly hydrogenated terphenyl having an oxygen atom ; an alkylbenzene derivative having 10 derivative and t -butylbenzene , a combination of a partly one or more tertiary carbon atoms directly bonded to the hydrogenated terphenyl derivative and t- amylbenzene , a benzene ring and a partly fluorinated aromatic compound ; an combination of a partly hydrogenated terphenyl derivative alkylbenzene derivative having one or more tertiary carbon and diphenyl ether , a combination of a partly hydrogenated atoms directly bonded to the benzene ring and a fluorine terphenyl derivative and dibenzofuran , a combination of a containing anisole compound : an alkylbenzene derivative 15 partly hydrogenated terphenyl derivative and fluorobenzene , having a quaternary carbon atom directly bonded to the a combination of a partly hydrogenated terphenyl derivative benzene ring and an aromatic compound having an oxygen and benzotrifluoride, a combination of a partly hydrogenated ato terphenyl derivative and 2 - fluorobiphenyl, a combination of bon atom directly bonded to the benzene ring and a partly a partly hydrogenated terphenyl derivative and o - fluorocy fluorinated aromatic compound ; an alkylbenzene derivative 20 clohexylbenzene, a combination of a partly hydrogenated having a quaternary carbon atom directly bonded to the terphenyl derivative and p - fluorocyclohexylbenzene , a com benzene ring and a fluorine -containing anisole compound ; bination of a partly hydrogenated terphenyl derivative and an aromatic compound having an oxygen atom and a partly 2 , 4 - difluoroanisole , fluorinated aromatic compound ; an aromatic compound hav - a combination of cumene and cyclopentylbenzene , a com ing an oxygen atom and a fluorine - containing anisole com - 25 bination of cumene and cyclohexylbenzene , a combination pound ; and a partly fluorinated aromatic compound and a of cumene and t -butylbenzene , a combination of cumene fluorine- containing anisole compound . and t - amylbenzene , a combination of cumene and diphenyl Specific examples thereof include ether, a combination of cumene and dibenzofuran , a com a combination of biphenyl and o - terphenyl, a combination of bination of cumene and fluorobenzene, a combination of biphenyl and m -terphenyl , a combination of biphenyl and a 30 cumene and benzotrifluoride , a combination of cumene and partly hydrogenated terphenyl derivative , a combination of 2 - fluorobiphenyl, a combination of cumene and o - fluorocy biphenyl and cumene , a combination of biphenyl and cyclo - clohexylbenzene , a combination of cumene and p - fluorocy pentylbenzene, a combination of biphenyl and cyclohexyl - clohexylbenzene, a combination of cumene and 2 , 4 - difluo benzene, a combination of biphenyl and t -butylbenzene , a roanisole , combination of biphenyl and t - amylbenzene , a combination 35 a combination of cyclohexylbenzene and t - butylbenzene, a of biphenyl and diphenyl ether, a combination of biphenyl combination of cyclohexylbenzene and t - amylbenzene , a and dibenzofuran , a combination of biphenyl and fluoroben combination of cyclohexylbenzene and diphenyl ether, a zene , a combination of biphenyl and benzotrifluoride , a combination of cyclohexylbenzene and dibenzofuran , a combination of biphenyl and 2 - fluorobiphenyl, a combina combination of cyclohexylbenzene and fluorobenzene , a tion of biphenyl and o - fluorocyclohexylbenzene , a combi- 40 combination of cyclohexylbenzene and benzotrifluoride , a nation of biphenyl and p - fluorocyclohexylbenzene , a com - combination of cyclohexylbenzene and 2 -fluorobiphenyl , a bination of biphenyl and 2 , 4 - difluoroanisole , combination of cyclohexylbenzene and o - fluorocyclohexyl a combination of o - terphenyl and a partly hydrogenated benzene , a combination of cyclohexylbenzene and p - fluo terphenyl derivative , a combination of o - terphenyl and rocyclohexylbenzene , a combination of cyclohexylbenzene cumene, a combination of o -terphenyl and cyclopentylben - 45 and 2 , 4 - difluoroanisole , zene , a combination of o - terphenyl and cyclohexylbenzene , a combination of t -butylbenzene and t -amylbenzene , a com a combination of o -terphenyl and t - butylbenzene , a combi- bination of t -butylbenzene and diphenyl ether, a combina nation of o - terphenyl and t - amylbenzene , a combination of tion of t -butylbenzene and dibenzofuran , a combination of 0 -terphenyl and diphenyl ether, a combination of o -terphe - t - butylbenzene and fluorobenzene , a combination of t - bu nyl and dibenzofuran , a combination of o - terphenyl and 50 tylbenzene and benzotrifluoride , a combination of t -butyl fluorobenzene , a combination of o - terphenyl and benzotri- benzene and 2 - fluorobiphenyl, a combination of t -butylben fluoride , a combination of o - terphenyl and 2 - fluorobiphenyl, zene and o - fluorocyclohexylbenzene, a combination of a combination of o - terphenyl and o - fluorocyclohexylben - t - butylbenzene and p - fluorocyclohexylbenzene, a combina zene , a combination of o - terphenyl and p - fluorocyclohex - tion of t -butylbenzene and 2 , 4 - difluoroanisole , ylbenzene , a combination of o - terphenyl and 2 ,4 -difluoro - 55 a combination of t- amylbenzene and diphenyl ether, a com anisole , bination of t -amylbenzene and dibenzofuran , a combination a combination of m -terphenyl and a partly hydrogenated oft- amylbenzene and fluorobenzene , a combination of t - am terphenyl derivative , a combination of m - terphenyl and ylbenzene and benzotrifluoride , a combination of t - amyl cumene, a combination of m - terphenyl and cyclopentylben - benzene and 2 - fluorobiphenyl, a combination of t - amylben zene , a combination of m - terphenyl and cyclohexylbenzene , 60 zene and o - fluorocyclohexylbenzene, a combination of a combination of m -terphenyl and t -butylbenzene , a com - t - amylbenzene and p - fluorocyclohexylbenzene, a combina bination of m - terphenyl and t- amylbenzene , a combination tion of t- amylbenzene and 2 ,4 -difluoroanisole , of m - terphenyl and diphenyl ether , a combination of m - ter - a combination of diphenyl ether and dibenzofuran , a com phenyl and dibenzofuran , a combination of m -terphenyl and bination of diphenyl ether and fluorobenzene , a combination fluorobenzene , a combination of m - terphenyl and benzotri - 65 of diphenyl ether and benzotrifluoride , a combination of fluoride, a combination of m - terphenyl and 2 - fluorobiphe - diphenyl ether and 2 - fluorobiphenyl, a combination of nyl, a combination of m - terphenyl and o - fluorocyclohexyl diphenyl ether and o - fluorocyclohexylbenzene, a combina US 9 ,853 , 326 B2 35 36 tion of diphenyl ether and p - fluorocyclohexylbenzene, a [ 2 . Nonaqueous -Electrolyte Secondary Battery ] combination of diphenyl ether and 2 , 4 -difluoroanisole , The nonaqueous- electrolyte secondary battery of this a combination of dibenzofuran and fluorobenzene , a com invention is constituted of the nonaqueous electrolyte of the bination of dibenzofuran and benzotrifluoride , a combina - invention described above and a positive electrode and a tion of dibenzofuran and 2 - fluorobiphenyl, a combination of 5 negative electrode which are capable of occluding and dibenzofuran and o - fluorocyclohexylbenzene , a combinahina releasing ions. The nonaqueous- electrolyte secondary bat tion of dibenzofuran and p - fluorocyclohexylbenzene , a com tery of the invention may be equipped with other constitu tions. bination of dibenzofuran and 2 ,4 - difluoroanisole , < 2 - 1 . Battery Constitution > a combination of fluorobenzene and benzotrifluoride , a 10 The constitution of the nonaqueous- electrolyte secondary combination of fluorobenzene and 2 - fluorobiphenyl, a com battery of the invention , excluding the negative electrode bination of fluorobenzene and o -fluorocyclohexylbenzene , a and the nonaqueous electrolyte, may be the same as that of combination of fluorobenzene and p - fluorocyclohexylben conventionally known nonaqueous- electrolyte secondary zene , a combination of fluorobenzene and 2 , 4 - difluoroani batteries . Usually , the battery of the invention has a consti sole, 15 tution including a positive electrode and a negative electrode a combination of benzotrifluoride and 2 - fluorobiphenyl, a which have been superposed through a porous film (sepa combination of benzotrifluoride and o - fluorocyclohexylben - rator ) impregnated with the nonaqueous electrolyte of the zene, a combination of benzotrifluoride and p - fluorocyclo - invention , the electrodes and the separator being held in a hexylbenzene , a combination of benzotrifluoride and 2 , 4 case . Consequently, the shape of the nonaqueous - electrolyte difluoroanisole , 20 secondary battery of the invention is not particularly limited , a combination of 2 - fluorobiphenyl and o - fluorocyclohexyl - and may be any of the cylindrical type, prismatic type , benzene , a combination of 2 - fluorobiphenyl and p - fluoro - laminate type , coin type , large type , and the like . cyclohexylbenzene , a combination of 2 - fluorobiphenyl and < 2 - 2 . Nonaqueous Electrolyte > 2 , 4 -difluoroanisole , As the nonaqueous electrolyte , the nonaqueous electrolyte a combination of o - fluorocyclohexylbenzene and p - fluoro - 25 of the invention described above is used . Incidentally , a cyclohexylbenzene, a combination of o - fluorocyclohexyl - mixture of the nonaqueous electrolyte of the invention and benzene and 2 , 4 -difluoroanisole , and a combination of another nonaqueous electrolyte may be used so long as this p - fluorocyclohexylbenzene and 2 , 4 - difluoroanisole, and the is not counter to the spirit of the invention . like . < 2 - 3 . Negative Electrode > In the case where nonaqueous electrolyte 1 of the inven - 30 Negative -electrode active materials usable in the negative tion contains an overcharge inhibitor, the concentration electrode are described below . thereof may be any value unless this considerably lessens The negative - electrode active materials are not particu the effects of the invention 1 . It is , however, desirable that larly limited so long as these are capable of electrochemi the concentration thereof should be regulated so as to be in cally occluding /releasing lithium ions . Examples thereof the range of generally from 0 . 1 % by mass to 5 % by mass 35 include a carbonaceous material, an alloy material , and a based on the whole nonaqueous electrolyte . lithium - containing metal composite oxide material. To incorporate an overcharge inhibitor into nonaqueous < 2 - 3 - 1 . Carbonaceous Material> electrolyte 1 of the invention in such an amount as not to The carbonaceous material to be used as a negative considerably lessen the effects of invention 1 is preferred electrode active material preferably is one which is selected because the nonaqueous -electrolyte secondary battery has 40 from : improved safety even if overcharged due to an erroneous ( 1 ) natural graphites ; usage or under a situation in which an overcharge protection ( 2 ) artificial carbonaceous substances and carbonaceous circuit does notwork normally , such as, e .g ., charger abnor- materials obtained by subjecting artificial graphitic sub mality . stances to a heat treatment at a temperature in the range of < 1 - 4 - 2 - 2 . Aids for Improving Capacity Retentivity and 45 400 - 3 , 200° C . one or more times; Cycle Characteristics after High - Temperature Storage > ( 3 ) carbonaceous materials giving a negative -electrode Examples of the aids for improving capacity retentivity active -material layer which is composed of at least two and cycle characteristics after high - temperature storage carbonaceous substances differing in crystallinity and /or has include an interface where at least two carbonaceous substances the anhydrides of dicarboxylic acids such as succinic acid , 50 differing in crystallinity are in contact with each other, and maleic acid , and phthalic acid ; ( 4 ) carbonaceous materials giving a negative -electrode carbonate compounds other than the specific carbonates, active -material layer which is composed of at least two such as erythritan carbonate and spiro - bis - dimethylene car - carbonaceous substances differing in orientation and / or has bonate ; sulfur- containing compounds such as ethylene an interface where at least two carbonaceous substances sulfite , 1 , 3 - propanesultone , 1 , 4 -butanesultone , methylmeth - 55 differing in orientation are in contact with each other. This anesulfonate , busulfan , sulfolane , sulfolene , dimethyl sul is because this carbonaceous material brings about a satis fone , diphenyl sulfone , methyl phenyl sulfone , dibutyl dis - factory balance between initial irreversible capacity and ulfide, dicyclohexyl disulfide, tetramethylthiuram high - current- density charge /discharge characteristics. One monosulfide , N , N -dimethylmethanesulfonamide , and N , N - of the carbonaceous materials ( 1 ) to ( 4 ) may be used alone , diethylmethanesulfonamide ; 60 or any desired combination of two or more thereof in any nitrogen - containing compounds such as 1 -methyl - 2 -pyrro - desired proportion may be used . lidinone , 1 -methyl - 2 - piperidone , 3 -methyl - 2 - oxazolidinone , Examples of the artificial carbonaceous substances and 1 ,3 -dimethyl - 2 - imidazolidinone, and N -methylsuccinimide ; artificial graphitic substances in (2 ) above include natural hydrocarbon compounds such as heptane, octane, and cyclo - graphites, coal coke, petroleum coke, coal pitch , petroleum heptane ; and 65 pitch , carbonaceous substances obtained by oxidizing these fluorine - containing aromatic compounds such as fluoroben - pitches , needle coke , pitch coke , carbon materials obtained Zezene , difluorobenzene, and benzotrifluoride . by partly graphitizing these cokes , products of the pyrolysis US 9 ,853 , 326 B2 37 38 of organic substances , such as furnace black , acetylene ( 2 ) Ash Content black , and pitch - derived carbon fibers , organic substances The ash content of the carbonaceous material is preferably capable of carbonization and products of the carbonization 1 % by mass or lower, especially 0 . 5 % by mass or lower, in thereof, or solutions obtained by dissolving any of such particular 0 . 1 % by mass or lower , based on the whole - 5 carbonaceous material. The lower limit of the ash content organic substances capable of carbonization in a low -mo - 5 thereof is preferably at least 1 ppm by mass of the whole lecular organic solvent, e .g . , benzene , toluene , xylene , qui carbonaceous material. When the ash content by mass noline , or n - hexane, and products of the carbonization of thereof exceeds the upper limit of that range, there are cases these solutions . where battery performance deterioration caused by reaction Examples of the organic substances capable of carbon with the nonaqueous electrolyte during charge /discharge ization include coal tar pitches ranging from soft pitch to becomes not negligible . When the ash content thereof is hard pitch , coal- derived heavy oil such as dry distillation lower than the lower limit of that range , there are cases liquefaction oil , straight- run heavy oil such as topping where the production of this carbonaceous material neces residues and vacuum distillation residues , heavy oils result sitates much time and energy and an apparatus for pollution prevention , resulting in an increase in cost . ing from petroleum cracking , such as ethylene tar as a 1515 (3 ) Volume- Average Particle Diameter by - product of the thermal cracking of crude oil , naphtha , With respect to the volume - average particle diameter of etc . , aromatic hydrocarbons such as acenaphthylene , deca the carbonaceous material, the volume -average particle cyclene , anthracene , and phenanthrene, nitrogen - atom - con diameter (median diameter ) thereof as determined by the taining heterocyclic compounds such as phenazine and laser diffraction / scattering method is generally 1 um or acridine , sulfur- atom -containing heterocyclic compounds 20 larger, preferably 3 um or larger, more preferably 5 um or such as thiophene and bithiophene , polyphenylenes such as larger, especially preferably 7 um or larger, and is generally biphenyl and terphenyl, poly (vinyl chloride ), poly (vinyl 100 um or smaller, preferably 50 um or smaller, more alcohol) , poly (vinyl butyral) , substances obtained by insolu preferably 40 um or smaller , even more preferably 30 um or bilizing these compounds , nitrogen - containing organic poly - smaller , especially preferably 25 um or smaller . When the mers such as polyacrylonitrile and polypyrrole , sulfur- con - 25 volume -average particle diameter thereof is smaller than the taining organic polymers such as polythiophene, organic lower limit of that range , there are cases where irreversible polymers such as polystyrene , natural polymers such as capacity increases, leading to a loss in initial battery capac polysaccharides represented by cellulose, lignin , mannan , ity . When the volume- average particle diameter thereof poly ( galacturonic acid ) , chitosan , and saccharose , thermo exceeds the upper limit of that range , there are cases where plastic resins such as poly (phenylene sulfide ) and poly 30 such a carbonaceous material is undesirable from the stand (phenylene oxide ), and thermosetting resins such as furfuryl point of battery production because an uneven coating alcohol resins, phenol- formaldehyde resins, and imide res - surface is apt to result when an electrode is produced ins , and the like . through coating fluid application . < 2 - 3 - 2 . Constitution and Properties of Carbonaceous Nega Volume- average particle diameter is determined by dis tive Electrode and Method of Preparation Thereof> 35 persing the carbon powder in a 0 . 2 % by mass aqueous With respect to the properties of the carbonaceous mate - solution (about 10 mL ) of poly ( oxyethylene ( 20 ) ) sorbitan rial, negative electrode containing the carbonaceous mate monolaurate as a surfactant and examining the dispersion rial, method of electrode formation , current collector, and with a laser diffraction / scattering type particle size distribu nonaqueous -electrolyte secondary battery , it is desirable that tion analyzer (LA -700 , manufactured by HORIBA , Ltd . ) . any one of the following ( 1 ) to (21 ) should be satisfied or 40 The median diameter determined through this measurement two or more thereof be simultaneously satisfied . is defined as the volume- average particle diameter of the ( 1 ) X -Ray Parameter carbonaceous material in the invention . The carbonaceous material preferably has a value of d ( 4 ) Raman R Value , Raman Half - Value Width ( interplanar spacing ) for the lattice planes (002 ), as deter - The Raman R value of the carbonaceous material as mined by X -ray diffractometry in accordance with the 45 determined by the argon ion laser Raman spectroscopy is method of the Japan Society for Promotion of Scientific generally 0 .01 or higher, preferably 0 . 03 or higher, more Research , of generally 0 . 335 - 0 .340 nm , especially 0 . 335 - preferably 0 . 1 or higher, and is generally 1 . 5 or lower , 0 .338 nm , in particular 0 . 335 - 0 . 337 nm . The crystallite size preferably 1 . 2 or lower, more preferably 1 or lower, espe (Lc ) thereof, as determined by X - ray diffractometry in cially preferably 0 . 5 or lower . accordance with the method of the Japan Society for Pro - 50 When the Raman R value thereof is lower than the lower motion of Scientific Research , is generally 1 . 0 nm or larger, limit of that range , the surface of such particles has too high preferably 1. 5 nm or larger , especially preferably 2 nm or crystallinity and there are cases where the number of inter larger. calation sites into which lithium comes with charge / dis A preferred material obtained by coating the surface of a charge decreases . Namely, there are cases where suitability graphite with amorphous carbon is one which is constituted 55 for charge decreases . In addition , when a coating fluid of a graphite having a value of d for the lattice planes (002 ) containing such a carbonaceous material is applied to a as determined by X - ray diffractometry of 0 . 335 -0 . 338 nm as current collector and the resultant coating is pressed to a core material and , adherent to the surface thereof, a heighten the density of the negative electrode , then the carbonaceous material having a larger value of d for the crystals are apt to orient in directions parallel to the electrode lattice planes (002 ) as determined by X - ray diffractometry 60 plate and this may lead to a decrease in load characteristics . than the core material, and in which the proportion of the On the other hand , when the Raman R value thereof exceeds core material to the carbonaceous material having a larger the upper limit of that range , the surface of such particles has value of d for the lattice planes (002 ) as determined by X - ray reduced crystallinity and enhanced reactivity with the non diffractometry than the core material is from 99 / 1 to 80 / 20 aqueous electrolyte and this may lead to a decrease in in terms of weight ratio . By using this material , a negative 65 efficiency and enhanced gas evolution . electrode which has a high capacity and is less apt to react The Raman half- value width around 1 ,580 cm - l of the with the electrolyte can be produced . carbonaceous material is not particularly limited . However, US 9 ,853 , 326 B2 39 40 the half -value width thereof is generally 10 cm - 1 or larger, surface area measuring apparatus manufactured by Ohukura preferably 15 cm - or larger , and is generally 100 cm - - or Riken Co . , Ltd . ) by preliminarily drying a sample at 350° C . smaller, preferably 80 cm - - or smaller , more preferably 60 for 15 minutes in a nitrogen stream and then measuring the cm - or smaller , especially preferably 40 cm or smaller . specific surface area thereof by the gas- flowing nitrogen When the Raman half -value width thereof is smaller than the 5 adsorption BET one -point method using a nitrogen /helium lower limit of that range, the surface of such particleshas too mixture gas precisely regulated so as to have a nitrogen high crystallinity and there are cases where the number of pressure of 0 . 3 relative to atmospheric pressure . The specific intercalation sites into which lithium comes with charge ! discharge decreases . Namely , there are cases where suitabil surface area determined through this measurement is defined ity for charge decreases . In addition , when a coating fluid 10 as the BET specific surface area of the carbonaceous mate containing such a carbonaceous material is applied to a rial in the invention . current collector and the resultant coating is pressed to (6 ) Pore Diameter Distribution heighten the density of the negative electrode , then the The pore diameter distribution of the carbonaceous mate crystals are apt to orient in directions parallel to the electrode rial is calculated through a measurement of the amount of plate and this may lead to a decrease in load characteristics. 15 intruded mercury . It is desirable that the carbonaceous On the other hand , when the Raman half - value width thereof material should have a pore diameter distribution in which exceeds the upper limit of that range , the surface of such the amount of interstices which correspond to pores having particles has reduced crystallinity and enhanced reactivity a diameter of from 0 .01 um to 1 um and which include pores with the nonaqueous electrolyte and this may lead to a within the particles, particle surface irregularities formed by decrease in efficiency and enhanced gas evolution . 20 steps , and pores attributable to contact surfaces among the The examination for a Raman spectrum is made with a particles , as determined by mercury porosimetry (mercury Raman spectrometer (Raman spectrometer manufactured by intrusion method ), is generally 0 .01 cm . g - or larger, pref Japan Spectroscopic Co ., Ltd .) . In the examination , a sample erably 0 .05 cm°. g - or larger, more preferably 0 . 1 cm°. g - or is charged into a measuring cell by causing the sample to fall larger, and is generally 0 .6 cm . g - or smaller, preferably 0 . 4 naturally into the cell and the surface of the sample in the 25 cm . g - or smaller, more preferably 0 . 3 cmg - or smaller. cell is irradiated with argon ion laser light while rotating the When the pore diameter distribution thereof is larger than cell in a plane perpendicular to the laser light. The Raman the upper limit of that range , there are cases where a large spectrum obtained is examined for the intensity IA of a peak amount of a binder is necessary in electrode plate formation . P , around 1 ,580 cm - ? and the intensity le of a peak PR When the amount of interstices thereof is smaller than the around 1 , 360 cm . The ratio between these intensities 30 lower limit of that range , there are cases where high - current R ( R = IP /14 ) is calculated . The Raman R value calculated density charge /discharge characteristics decrease and the through this examination is defined as the Raman R value of effect of diminishing electrode expansion / contraction during the carbonaceous material in the invention . Furthermore , the charge / discharge is not obtained . half- value width of the peak P , around 1 ,580 cm - l in the The total volume of pores thereof corresponding to the Raman spectrum obtained is measured , and this value is 35 pore diameter range of from 0 . 01 um to 100 um , as deter defined as the Raman half - value width of the carbonaceous mined by mercury porosimetry (mercury intrusion method ) , material in the invention . is generally 0 . 1 cm°. g - or larger ,preferably 0 .25 cm°. g - or Conditions for the Raman spectroscopy are as follows. larger, more preferably 0 . 4 cm : g - or larger , and is gener Wavelength of argon ion laser : 514 . 5 nm ally 10 cm . g - or smaller , preferably 5 cmg - or smaller , Laser power on sample : 15 - 25 mW 40 more preferably 2 cmº. g - 1 or smaller. When the total pore Resolution : 10 - 20 cm volume thereof exceeds the upper limit of that range , there Examination range: 1 , 100 cm - 1 to 1, 730 cm - 1 are cases where a large amount of a binder is necessary in Analysis for Raman R value and Raman half -value width : electrode plate formation . When the total pore volume background processing thereof is smaller than the lower limit of that range , there are Smoothing : simple average ; convolution , 5 points 45 cases where the dispersing effect of a thickener or binder in ( 5 ) BET Specific Surface Area electrode plate formation is not obtained . The BET specific surface area of the carbonaceous mate - The average pore diameter thereof is generally 0 .05 um or rial, in terms of the value of specific surface area as larger, preferably 0 . 1 um or larger , more preferably 0 . 5 um determined by the BET method , is generally 0 . 1 m g - or or larger, and is generally 50 um or smaller, preferably 20 larger, preferably 0 . 7 m². g - or larger, more preferably 1 . 0 50 um or smaller, more preferably 10 um or smaller. When the m ' . g - or larger, especially preferably 1 . 5 m². g - or larger , average pore diameter thereof exceeds the upper limit of that and is generally 100 m². g - or smaller , preferably 25 m². g . range , there are cases where a large amount of a binder is or smaller, more preferably 15 m². g - or smaller , especially necessary. When the average pore diameter thereof is preferably 10 m². g - or smaller. When the BET specific smaller than the lower limit of that range , there are cases surface area thereof is smaller than the lower limit of that 55 where high -current - density charge/ discharge characteristics range, use of this carbonaceous material as a negative - decrease . electrode material is apt to result in poor lithium acceptance The amount of mercury intruded is measured with a during charge and in lithium deposition on the electrode mercury porosimeter (Autopore 9520 , manufactured by surface . Consequently , there is the possibility of resulting in Micromeritics Corp . ) as an apparatus for the mercury poro reduced stability . On the other hand , when the specific 60 simetry . A sample is pretreated by placing about 0 . 2 g of the surface area thereof exceeds the upper limit of that range , sample in a powder cell, closing the cell , and degassing the there are cases where use of this carbonaceous material as a sample at room temperature under vacuum (50 umHg or negative - electrode material is apt to result in enhanced lower) for 10 minutes. Subsequently, the pressure in the cell reactivity with the nonaqueous electrolyte and enhanced gas is reduced to 4 psia ( about 28 kPa ) and mercury is intro evolution and a preferred battery is difficult to obtain . 65 duced thereinto . The internal pressure is stepwise elevated The determination of specific surface area by the BET from 4 psia (about 28 kPa ) to 40 ,000 psia (about 280 MPa) method is made with a surface area meter ( a fully automatic and then lowered to 25 psia ( about 170 kPa ) . The number of US 9 ,853 , 326 B2 steps in the pressure elevation is 80 or larger . In each step . The true density of the carbonaceous material is deter the amount of mercury intruded is measured after an equi- mined by the liquid - phase displacement method ( pyconom librium time of 10 seconds. eter method ) using butanol. The value determined through A pore diameter distribution is calculated from the mer this measurement is defined as the true density of the cury intrusion curve thus obtained , using the Washburn 5 carbonaceous material in the invention . equation . Incidentally , the surface tension ( y ) and contact ( 9 ) Tap Density angle (H ) ofmercury are taken as 485 dyne cm - ? ( 1 dyne = 10 The tap density of the carbonaceous material is generally RN ) and 140°, respectively . The average pore diameter used 0 .1 g .cm - > or higher, preferably 0 .5 g .cm - or higher , more is the pore diameter corresponding to a cumulative pore preferably 0 . 7 g . cm or higher, especially preferably 1 volume of 50 % . 10 g .cm -> or higher, and is preferably 2 g .cm -> or lower , more ( 7 ) Roundness preferably 1 . 8 g . cm3 or lower , especially preferably 1 . 6 When the carbonaceous material is examined for round - gcm - 3 or lower . When the tap density thereof is lower than ness as an index to the degree of sphericity thereof, the the lower limit of that range , there are cases where this roundness thereof is preferably within the range shown carbonaceous material, when used in a negative electrode, is below . Roundness is defined by “ Roundness = ( length of 15 less apt to have a high loading density and cannot give a periphery of equivalent circle having the same area as battery having a high capacity . On the other hand , when the projected particle shape )/ ( actual length of periphery of pro - tap density thereof exceeds the upper limit of that range , the jected particle shape ) ” . When a particle has a roundness of amount of interparticle interstices in the electrode is too 1 , this particle theoretically is a true sphere . small and it is difficult to secure electrical conductivity The closer to 1 the roundness of carbonaceous- material 20 among the particles. There are hence cases where preferred particles having a particle diameter in the range of 3 - 40 um , battery performances are difficult to obtain . the more the particles are desirable. The roundness of the Tap density is determined by dropping a sample through particles is desirably 0 . 1 or higher , preferably 0 .5 or higher, a sieve having an opening size of 300 um into a 20 cm more preferably 0 . 8 or higher, even more preferably 0 .85 or tapping cell to fill the cell with the sample up to the brim , higher, especially preferably 0 . 9 or higher . 25 subsequently conducting tapping operations 1 ,000 times The higher the roundness , the more the high -current - over a stroke length of 10 mm using a powder densimeter density charge /discharge characteristics are improved . Con - (e . g ., Tap Denser, manufactured by Seishin Enterprise Co ., sequently, when the roundness of the carbonaceous -material Ltd . ), and calculating the tap density from the resultant particles is lower than the lower limit of that range , there are volume of the sample and the weight thereof. The tap density cases where the negative - electrode active material has 30 calculated through this measurement is defined as the tap reduced suitability for loading and interparticle resistance is density of the carbonaceous material in the invention . increased , resulting in reduced short- time high - current- den - ( 10 ) Orientation Ratio sity charge / discharge characteristics . The orientation ratio of the carbonaceous material is Roundness is determined with a flow type particle image generally 0 .005 or higher, preferably 0 .01 or higher , more analyzer ( FPIA , manufactured by Sysmex Industrial Corp . ). 35 preferably 0 .015 or higher , and is generally 0 .67 or lower . About 0 . 2 g of a sample is dispersed in a 0 . 2 % by mass When the orientation ratio thereof is lower than the lower aqueous solution (about 50 mL ) of poly (oxyethylene ( 20 ) limit of that range, there are cases where high -density sorbitan monolaurate as a surfactant, and an ultrasonic wave charge /discharge characteristics decrease . The upper limit of of 28 kHz is propagated to the dispersion for 1 minute at an that range is a theoretical upper limit of the orientation ratio output of 60 W . Thereafter , particles having a particle 40 of carbonaceous materials . diameter in the range of 3 -40 um are examined with the Orientation ratio is determined by X - ray diffractometry analyzer having a detection range set at 0 .6 - 400 um . The after a sample is molded by compaction . Amolding obtained roundness determined through this measurement is defined by packing 0 .47 g of a sample into a molding machine as the roundness of the carbonaceous material in the inven - having a diameter of 17 mm and compacting the sample at tion . 45 58 . 8 MN .mº ? is set with clay on a sample holder for Methods for improving roundness are not particularly examination so as to be flush with the holder. This sample limited . However, a carbonaceous material in which the molding is examined for X - ray diffraction . From the inten particles have been rounded by a rounding treatment is sities of the resultant ( 110 ) diffraction peak and ( 004 ) preferred because it gives an electrode in which the inter - diffraction peak for the carbon , the ratio represented by ( 110 ) stices among particles are uniform in shape . Examples of the 50 diffraction peak intensity / ( 004 ) diffraction peak intensity is rounding treatment include : a method in which a shear force calculated . The orientation ratio calculated through this or compressive force is applied to thereby mechanically measurement is defined as the orientation ratio of the make the shape of the particles close to sphere ; and a method carbonaceous material in the invention . ofmechanical / physical treatment in which fine particles are Conditions for the X - ray diffractometry are as follows. aggregated into particles by means of the bonding force of 55 Incidentally , “ 20 ” represents diffraction angle . a binder or of the fine particles themselves . Target: Cu (Ka line ) graphite monochromator ( 8 ) True Density Slit : The true density of the carbonaceous material is generally Divergence slit = 0 . 5 degrees 1 . 4 g•cm -> or higher , preferably 1 .6 g . cm - 3 or higher, more Receiving slit = 0 . 15 mm preferably 1 . 8 g . cm or higher , especially preferably 2 . 0 60 Scattering slit = 0 . 5 degrees g . cm - 3 or higher, and is generally 2 . 26 g . cm - 3 or lower. Examination range and step angle /measuring time: When the true density of the carbonaceous material is lower ( 110 ) plane : 75ºs20580° 1° /60 sec than the lower limit of that range , there are cases where this (004 ) plane : 52°520557° 1 /60 sec carbon has too low crystallinity , resulting in an increase in ( 11 ) Aspect Ratio ( Powder ) initial irreversible capacity . Incidentally , the upper limit of 65 The aspect ratio of the carbonaceous material is generally that range is a theoretical value of the true density of 1 or higher, and is generally 10 or lower, preferably 8 or graphites . lower, more preferably 5 or lower. When the aspect ratio US 9 ,853 , 326 B2 43 44 thereof exceeds the upper limit of that range , there are cases a nonaqueous electrolyte in battery fabrication is generally where this carbonaceous material causes streak lines in 15 um or larger, preferably 20 um or larger, more preferably electrode plate formation and an even coating surface cannot 30 um or larger, and is generally 150 um or smaller, be obtained , resulting in a decrease in high -current - density preferably 20 um or smaller, more preferably 100 um or charge / discharge characteristics. Incidentally , the lower 5 smaller. The reasons for this are as follows. When the limit of that range is a theoretical lower limit of the aspect thickness of the negative - electrode active -material layer is ratio of carbonaceous materials . larger than the upper limit of that range , a nonaqueous In determining aspect ratio , particles of the carbonaceous electrolyte is less apt to infiltrate into around the interface of material are examined with a scanning electron microscope the current collector and , hence , there are cases where with enlargement. Fifty are arbitrarily selected from graphite 10 high - current- density charge /discharge characteristics particles fixed to an edge face of a metal having a thickness decrease . When the thickness thereof is smaller than the of 50 um or smaller, and each particle is examined in a lower limit of that range , the proportion by volume of the three - dimensional manner while rotating or inclining the current collector to the negative - electrode active material stage to which the sample is fixed . In this examination , the increases and there are cases where battery capacity length of the longest axis A of each carbonaceous -material 15 decreases . The negative - electrode active material may be particle and the length of the shortest axis B perpendicular roller- pressed to obtain a sheet electrode , or may be sub to that axis are measured , and the average of the A /B values jected to compression molding to obtain a pellet electrode . is determined . The aspect ratio ( A / B ) determined through ( 14 ) Current Collector this measurement is defined as the aspect ratio of the As the current collector for holding the negative - electrode carbonaceous material in the invention . 20 active material , a known one can be used at will. Examples ( 12 ) Minor -Material Mixing of the current collector for the negative electrode include Minor -material mixing means that the negative electrode metallic materials such as copper, nickel, stainless steel, and and /or the negative- electrode activematerial contains two or nickel - plated steel. Copper is especially preferred from the more carbonaceous materials differing in property . The term standpoints of processability and cost. property herein means one or more properties selected from 25 In the case where the current collector is a metallic the group consisting of X - ray diffraction parameter , median material, examples of the shape of the current collector diameter, aspect ratio , BET specific surface area , orientation include metal foils , metal cylinders , metal coils , metal ratio , Raman R value, tap density , true density , pore distri plates, thin metal films, expanded metals , punching metals , bution , roundness , and ash content. and metal foams. Preferred of these are thin metal films . Especially preferred examples of the minor- material mix - 30 More preferred are copper foils . Even more preferred are a ing include : one in which the volume- based particle size rolled copper foil , which is produced by the rolling process , distribution is not symmetrical about the median diameter ; and an electrolytic copper foil, which is produced by the one in which two or more carbonaceous materials differing electrolytic process . Either of these can be used as a current in Raman R value are contained ; and one in which carbo - collector. naceous materials differing in X -ray parameter are con - 35 In the case of a copper foil having a thickness smaller than tained . 25 um , use can be made of a copper alloy (e .g . , phosphor One example of the effects of the minor- material mixing bronze , titanium -copper , Corson alloy , or Cu : Cr: Zr alloy ) is that the incorporation of a carbonaceousmaterial , such as having a higher strength than pure copper. a graphite , e . g ., a natural graphite or artificial graphite , or an The current collector constituted of a copper foil produced amorphous carbon , e . g . , a carbon black such as acetylene 40 by the rolling process is less apt to crack even when the black or needle coke , as a conductive material serves to negative electrode is rolled tightly or rolled at an acute reduce electrical resistance . angle , because the copper crystals are oriented in the rolling In the case where conductive materials are incorporated as direction . This current collector can be advantageously used minor- material mixing , one conductive material may be in small cylindrical batteries. incorporated alone or any desired combination of two or 45 The electrolytic copper foil is obtained by immersing a more conductive materials in any desired proportion may be metallic drum in a nonaqueous electrolyte containing copper incorporated . The proportion of the conductive material ( s ) ions dissolved therein , causing current to flow through the to be incorporated is generally 0 . 1 % by mass or higher , system while rotating the drum to thereby deposit copper on preferably 0 . 5 % by mass or higher , more preferably 0 . 6 % by the drum surface , and peeling the copper deposit from the mass or higher, and is generally 45 % by mass or lower , 50 drum . Copper may be deposited on a surface of the rolled preferably 40 % by mass or lower, based on the carbonaceous copper foil by the electrolytic process . One or each side of material . When the proportion thereof is lower than the such a copper foil may have undergone a surface - roughen lower limit of that range , there are cases where the effect of ing treatment or a surface treatment ( e . g . , a chromate treat improving conductivity is difficult to obtain . Proportions ment in a thickness of from several nanometers to about 1 thereof exceeding the upper limit of that range may lead to 55 um or a priming treatment with titanium ) . an increase in initial irreversible capacity . The current collector base is desired to further have the ( 13 ) Electrode Production following properties. Any known method can be used for electrode production ( 14 - 1) Average Surface Roughness (Ra ) unless this considerably lessens the effects of the invention . The average surface roughness (Ra ) of that side of the For example , a binder and a solvent are added to a negative - 60 current collector base on which a thin negative - electrode electrode active material optionally together with a thick active- material film is to be formed , as determined by the ener, conductive material, filler, etc . to obtain a slurry and method provided for in JIS B 0601 - 1994 , is not particularly this slurry is applied to a current collector and dried . limited . However, the average surface roughness thereof is Thereafter , the coated current collector is pressed , whereby generally 0 .05 um or higher, preferably 0 . 1 um or higher, an electrode can be formed . 65 more preferably 0 . 15 um or higher , and is generally 1 . 5 um The thickness of the negative - electrode active -material or lower, preferably 1 . 3 um or lower ,more preferably 1 . 0 um layer per one side in the stage just before the step of injecting or lower. This is because when the average surface rough US 9 ,853 , 326 B2 45 46 ness (Ra ) of the current collector base is within that range , (15 ) Thickness Ratio Between Current Collector and Nega satisfactory charge / discharge cycle characteristics can be tive - Electrode Active -Material Layer expected . In addition , the area of the interface between the The thickness ratio between the current collector and the base and a thin negative - electrode active -material film is negative -electrode active -material layer is not particularly increased and adhesion to the thin negative - electrode active - 5 limited . However , the value of “ ( thickness of the negative material film is improved . The upper limit of the average electrode active- material layer on one side just before surface roughness (Ra ) thereof is not particularly limited . impregnation with the nonaqueous electrolyte ) ( thickness of However , a current collector base having an Ra of 1 . 5 um or the current collector) ” is preferably 150 or smaller, more lower is usually employed because a foil having a practical preferably 20 or smaller , especially preferably 10 or smaller, thickness for batteries and having an average surface rough - and is preferably 0 . 1 or larger ,more preferably 0 . 4 or larger , ness (Ra ) exceeding 1 . 5 um is generally difficult to procure . especially preferably 1 or larger. (14 -2 ) Tensile Strength When the thickness ratio between the current collector Tensile strength is a quotient obtained by dividing the and the negative - electrode active -material layer exceeds the maximum tensile force required before test piece breakage 16 upper limit of that range , there are cases where this current by the sectional area of the test piece . In the invention , the collector heats up due to Joule ' s heat during high -current tensile strength is determined through a measurement con density charge / discharge . When that ratio decreases beyond ducted with the same apparatus and by the same method as the lower limit of that range, the proportion by volume of the those described in JIS Z 2241 (Method of Metallic -Material current collector to the negative -electrode active material Tensile Test ). 20 increases and this may reduce the capacity of the battery . The tensile strength of the current collector base is not ( 16 ) Electrode Density particularly limited . However, it is generally 100 N ·mm - 2 or When the negative -electrode active material is used to higher, preferably 250 N ·mm - 2 or higher , more preferably form an electrode , the electrode structure is not particularly 400 N ·mm ? or higher , especially preferably 500 N ·mm - 2 or limited . However, the density of the negative -electrode higher . The higher the tensile strength , the more the current 25 active material present on the current collector is preferably collector base is preferred . However, the tensile strength 1 g . cm - > or higher, more preferably 1 . 2 g .cm - > or higher, thereof is generally 1 , 000 N .mm - 2 or lower from the stand especially preferably 1 . 3 g . cm - 3 or higher , and is preferably point of industrial availability . A current collector base 2g .cm -> or lower ,more preferably 1 . 9 g -cm - 3 or lower , even having a high tensile strength can be inhibited from cracking more preferably 1 . 8 g .cm - > or lower, especially preferably with the expansion /contraction of the thin negative- elec - 30 1 .7 g . cm -3 or lower. When the density of the negative trode active -material film which occur upon charge /dis - electrode active material present on the current collector charge . With this current collector base , satisfactory cycle exceeds the upper limit of that range , there are cases where characteristics can be obtained . the negative - electrode active -material particles are broken ( 14 - 3 ) 0 . 2 % Proof Stress and this increases the initial irreversible capacity and The term 0 . 2 % proof stress means the degree of load 35 reduces the infiltration of a nonaqueous electrolyte into necessary for imparting a plastic ( permanent ) deformation of around the current collector /negative -electrode active mate 0 . 2 % . Namely , it means that application of that degree of rial interface . As a result, high - current- density charge /dis load and subsequent removal thereof result in a 0 . 2 % charge characteristics may decrease . When the density deformation . The 0 . 2 % proof stress is determined through a thereof is lower than the lower limit of that range , there are measurement conducted with the same apparatus and by the 40 cases where electrical conductivity among the negative same method as for tensile strength . electrode active -material particles decreases and this The 0 . 2 % proof stress of the current collector base is not increases battery resistance , resulting in a reduced capacity particularly limited . However, it is desirable that the 0 . 2 % per unit volume. proof stress thereof should be generally 30 N ·mm - 2 or ( 17 ) Binder higher , preferably 150 N ·mm - 2 or higher , especially prefer - 45 The binder for binding the negative - electrode active mate ably 300 N /mm² or higher. The higher the 0 . 2 % proof stress , rial is not particularly limited so long as it is stable to the the more the current collector base is preferred . However , nonaqueous electrolyte and to the solvent to be used for the 0 . 2 % proof stress thereof is generally desirably 900 electrode production . N•mm - 2 or lower from the standpoint of industrial avail - Examples thereof include resinous polymers such as ability . A current collector base having a high 0 . 2 % proof 50 polyethylene , polypropylene , poly (ethylene terephthalate ), stress can be inhibited from plastically deforming with the poly (methyl methacrylate ) , aromatic polyamides, cellulose , expansion /contraction of the thin negative - electrode active and nitrocellulose ; rubbery polymers such as SBR (styrene / material film which occur upon charge /discharge . With this butadiene rubbers ), isoprene rubbers, butadiene rubbers , current collector base , satisfactory cycle characteristics can fluororubbers , NBR ( acrylonitrile/ butadiene rubbers ) , and be obtained . 55 ethylene/ propylene rubbers; styrene/ butadiene / styrene block ( 14 - 4 ) Thickness of Current Collector copolymers or products of hydrogenation thereof ; thermo The current collector may have any desired thickness . plastic elastomeric polymers such as EPDM ( ethylene /pro However, the thickness thereof is generally 1 um or larger pylene /diene terpolymers ) , styrenelethylene / butadiene / sty preferably 3 um or larger, more preferably 5 um or larger, rene copolymers, and styrene / isoprene/ styrene block and is generally 1 mm or smaller , preferably 100 um or 60 copolymers or products of hydrogenation thereof; flexible smaller, more preferably 50 um or smaller. In case where the resinous polymers such as syndiotactic 1 , 2 -polybutadiene , current collector is thinner than 1 um , this collector has poly ( vinyl acetate ), ethylene / vinyl acetate copolymers , and reduced strength and there are hence cases where coating is propylene a -olefin copolymers ; fluorochemical polymers difficult. When the current collector is thicker than 100 there such as poly ( vinylidene fluoride ), polytetrafluoroethylene, are cases where this collector deforms an electrode shape , 65 fluorinated poly ( vinylidene fluoride ), and polytetrafluoro e . g ., a rolled form . The current collector may be in a mesh ethylenelethylene copolymers ; and polymer compositions form . having the property of conducting alkali metal ions ( espe US 9 ,853 , 326 B2 48 cially lithium ions) . One of these may be used alone , or any electrode active material is lower than the lower limit of that desired combination of two or more thereof in any desired range , there are cases where applicability decreases consid proportion may be used . erably . Proportions thereof exceeding the upper limit of that The kind of the solvent to be used for forming a slurry is range result in a reduced proportion of the negative - elec not particularly limited so long as it is a solvent in which the 5 trode active material in the negative - electrode active -mate negative - electrode active material and binder and the thick rial layer , and this may pose a problem that battery capacity ener and conductive material which are optionally used decreases and a problem that resistance among the particles according to need can be dissolved or dispersed . Either an of the negative - electrode active material increases . aqueous solvent or an organic solvent may be used . ( 18 ) Orientation Ratio in Electrode Plate Examples of the aqueous solvent include water and alco - 10 The orientation ratio in the electrode plate is generally hols . Examples of the organic solvent include N -methylpyr - 0 . 001 or higher , preferably 0 . 005 or higher, more preferably rolidone (NMP ) , dimethylformamide , dimethylacetamide , 0 .01 or higher , and is generally 0 .67 or lower. When the methyl ethyl ketone , cyclohexanone , methyl acetate , methyl orientation ratio therein is lower than the lower limit of that acrylate , diethyltriamine , N , N -dimethylaminopropylamine , range, there are cases where high -density charge /discharge tetrahydrofuran ( THF ) , toluene , acetone, diethyl ether, dim - 15 characteristics decrease . The upper limit of that range is a ethylacetamide , hexamethylphosphoramide , dimethyl sul- theoretical upper limit of orientation ratio in carbonaceous foxide , benzene , xylene , quinoline , pyridine, methylnaph material electrodes. thalene , and hexane , and the like . An examination for determining the orientation ratio in Especially when an aqueous solvent is used , it is preferred the electrode plate is as follows. The negative electrode to add a dispersant or the like in combination with a 20 which has been pressed to a target density is examined by thickener and prepare a slurry using a latex of, e . g ., SBR . X - ray diffractometry to determine the orientation ratio of the One of those solvents may be used alone, or any desired negative - electrode active material in this electrode. combination of two or more thereof in any desired propornor Although specific techniques therefor are not particularly tion may be used . limited , a standard method is as follows. The peaks attrib The proportion of the binder to the negative - electrode 25 utable to the (110 ) diffraction and (004 ) diffraction of the active material is preferably 0 . 1 % by mass or higher, more carbon obtained by X - ray diffractometry are subjected to preferably 0 . 5 % by mass or higher , especially preferably peak separation by fitting with asymmetric Pearson VII as a 0 . 6 % by mass or higher, and is preferably 20 % by mass or profile function . Thus , the integrated intensities of the (110 ) lower, more preferably 15 % by mass or lower, even more diffraction and (004 ) diffraction peaks are calculated . From preferably 10 % by mass or lower , especially preferably 8 % 30 the integrated intensities obtained , the ratio represented by by mass or lower. In case where the proportion of the binder integrated intensity of ( 110 ) diffraction ) / ( integrated inten to the negative - electrode active material exceeds the upper s ity of (004 ) diffraction ) is calculated . The negative - elec limit of that range , the proportion of the binder which does trode active -material orientation ratio for the electrode thus not contribute to battery capacity increases and this may lead calculated is defined as the orientation ratio in the electrode to a decrease in battery capacity . When the binder amount is 35 plate employing the carbonaceous material in the invention . small than the lower limit of that range , there are cases Conditions for this X - ray diffractometry are as follows. where the negative electrode has a reduced strength . Incidentally , “ 20 ” represents diffraction angle . Especially when the binder includes a rubbery polymer Target : Cu (Ka line ) graphite monochromator represented by SBR as the main component, the proportion Slit : of this binder to the negative - electrode active material is 40 Divergence slit = 1 degree generally 0 .1 % by mass or higher , preferably 0 .5 % by mass Receiving slit = 0 . 1 mm or higher , more preferably 0 . 6 % by mass or higher, and is Scattering slit = 1 degree generally 5 % by mass or lower, preferably 3 % by mass or Examination range and step angle /measuring time: lower, more preferably 2 % by mass or lower. ( 110 ) plane: 76 . 5°520578 .5° 0 .01° / 3 sec In the case where the binder includes a fluorochemical 45 (004 ) plane : 53 . 5ºs20556 .0° 0 .01° / 3 sec polymer represented by poly ( vinylidene fluoride) as the Sample preparation : main component, the proportion of this binder to the nega The electrode is fixed to a glass plate with a double- faced tive - electrode active material is generally 1 % by mass or pressure - sensitive adhesive tape having a thickness of 0 . 1 higher , preferably 2 % by mass or higher, more preferably mm . 3 % by mass or higher , and is generally 15 % by mass or 50 < 2 - 3 - 3 . Metal Compound Material, Constitution and Prop lower, preferably 10 % by mass or lower , more preferably erties of Negative Electrode Employing Metal Compound 8 % by mass or lower. Material, and Method of Preparation Thereof > A thickener is used generally for the purpose of regulating The metal compound material to be used as a negative the slurry viscosity . The thickener is not particularly limited electrode active material is not particularly limited so long Examples thereof include carboxymethyl cellulose, methyl 55 as the material is capable of occluding / releasing lithium . cellulose , hydroxymethyl cellulose , ethyl cellulose , poly Use may be made of an elemental metal or alloy which ( vinyl alcohol) , oxidized starch , phosphorylated starch , forms a lithium alloy or any of compounds thereof, such as casein , and salts of these . One of these thickeners may be oxides , carbides , nitrides, silicides , sulfides, and phosphides . used alone, or any desired combination of two or more Examples of such metal compounds include compounds thereof in any desired proportion may be used . 60 containing a metal such as Ag, A1, Ba , Bi, Cu , Ga, Ge, In , In the case where such a thickener is further added , the Ni, P, Pb , Sb , Si, Sn , Sr, or Zn . In particular, the negative proportion of the thickener to the negative -electrode active electrode active material preferably is an elemental metal or material is generally 0 . 1 % by mass or higher, preferably alloy which forms a lithium alloy. It is preferred that the 0 . 5 % by mass or higher, more preferably 0 .6 % by mass or active material should be a material containing any of the higher, and is generally 5 % by mass or lower, preferably 3 % 65 metals and semimetals in Group 13 and Group 14 ( i. e ., by mass or lower, more preferably 2 % by mass or lower. carbon is excluded ). Furthermore , it is preferred that the When the proportion of the thickener to the negative active material should be an elemental metal selected from US 9 ,853 , 326 B2 49 50 silicon ( Si) , tin (Sn ), and lead (Pb ) (hereinafter , these meals production include : a method in which a binder, a conduc are often referred to as “ specific metallic elements ” ) or an tive material, and other ingredients are added to any of the alloy or compound containing one or more atoms of any of negative -electrode active materials described above and this these metals . One of such materialmay be used alone , or any mixture is directly pressed by roller to form a sheet elec desired combination of two or more of these in any desired 5 trode ; and a method in which the mixture is compression proportion may be used . molded to form a pellet electrode . Usually , however, use is Examples of the negative - electrode active material made of a method in which a thin film layer containing any including atoms of at least one member selected from the of the negative - electrode active materials described above specific metallic elements include : the elemental metal (negative - electrode active -material layer ) is formed on a which is any one of the specific metallic elements ; alloys 10 current collector for negative electrodes (hereinafter some constituted of two or more specific metal elements , alloys times referred to as “ negative - electrode current collector” ) constituted of one or more specific metal elements and one by a technique such as , e . g ., coating fluid application , vapor or more metallic elements of another kind ; compounds deposition , sputtering , or plating . In this case , a negative containing one or more specific metallic elements; and electrode active -material layer may be formed on a negative composite compounds, e . g . , oxides , carbides , nitrides , sili- 15 electrode current collector by adding a binder, thickener, cides , sulfides , or phosphides , of these compounds. By using conductive material, solvent, etc. to the negative - electrode any of these elemental metals , alloys, and metal compounds active material to obtain a mixture in a slurry form , applying as a negative - electrode active material, a battery having a this mixture to the negative -electrode current collector, higher capacity can be obtained . drying the mixture applied , and then pressing the coated Examples of the negative - electrode activematerial further 20 current collector to densify the coating . include compounds formed by the complicated bonding of Examples of the material of the negative - electrode current any of those composite compounds to one or more elemental collector include steel , copper alloys, nickel , nickel alloys, metals or alloys or to several elements , e . g ., nonmetallic and stainless steel. Copper foils are preferred of these elements .More specifically , in the case of silicon and tin , for materials from the standpoints of processability into thin example , it is able to use an alloy of those elements with a 25 films and cost . metal which does not function as a negative electrode. In the The thickness of the negative - electrode current collector case of tin , for example , it is able to use a complicated is generally 1 um or larger , preferably 5 um or larger, and is compound constituted of a combination of five to six ele generally 100 um or smaller , preferably 50 um or smaller. ments including tin , a metal which functions as a negative The reasons for this are as follows. In case where the electrode and is not silicon , a metal which does not function 30 negative -electrode current collector is too thick , this may as a negative electrode , and a nonmetallic element. resultresult in too large a decrease in the capacity of the whole Preferred of those negative - electrode active materials are battery . Conversely , in case where the current collector is too the elementalmetal which is any one of the specific metallic thin , this collector may be difficult to handle . elements , alloys of two or more of the specific metallic It is preferred that the surface of each of those negative elements , and oxides , carbides , nitrides , and other com - 35 electrode current collectors should be subjected to a surface pounds of the specific metallic elements . This is because roughening treatment beforehand in order to improve the these negative - electrode active materials give a battery effect of binding the negative - electrode active- material layer having a high capacity per unit weight. Especially preferred to be formed on the surface. Examples of techniques for the are the elementalmetal ( s ) , alloys , oxides , carbides , nitrides, surface roughening include blasting , rolling press with a roll and the like of silicon and / or tin from the standpoints of 40 having a roughened surface , and mechanical polishing in capacity per unit weight and environmental burden . which the collector surface is polished with an abrasive cloth The following compounds containing silicon and /or tin or paper having abrasive particles fixed thereto , a grind also are preferred because these compounds bring about stone , an emery wheel, a wire brush equipped with steel excellent cycle characteristics, although inferior in capacity bristles , or the like . Examples thereof further include elec per unit mass to the elemental metals or alloys thereof . 45 trolytic polishing and chemical polishing . A silicon and /or tin oxide in which the elemental ratio of It is also possible to use a negative - electrode current the silicon and / or tin to the oxygen is generally 0 . 5 or higher, collector of the perforated type , such as an expanded metal preferably 0 . 7 or higher, more preferably 0 . 9 or higher , and or a punching metal, as a negative - electrode current collec is generally 1 . 5 or lower , preferably 1 . 3 or lower, more tor having a reduced weight in order to improve energy preferably 1 . 1 or lower. 50 density per unit weight of the battery . A negative - electrode A silicon and / or tin nitride in which the elemental ratio of current collector of this type can be varied in weight at will the silicon and / or tin to the nitrogen is generally 0 . 5 or by changing the percentage of openings thereof. Further higher , preferably 0 .7 or higher, more preferably 0 . 9 or more , in the case where a negative -electrode active- material higher , and is generally 1 . 5 or lower, preferably 1. 3 or lower, layer is formed on each side of a negative- electrode current more preferably 1 . 1 or lower. 55 collector of this type , the negative -electrode active - material A silicon and /or tin carbide in which the elemental ratio layers are even less apt to peel off because of the effect of of the silicon and / or tin to the carbon is generally 0 . 5 or ribetting through the holes. It should , however , be noted that higher , preferably 0 . 7 or higher, more preferably 0 . 9 or too high a percentage of openings results in a reduced higher , and is generally 1 . 5 or lower, preferably 1 . 3 or lower, contact area between each negative - electrode active -mate more preferably 1. 1 or lower . 60 rial layer and the negative - electrode current collector and Any one of the negative -electrode active materials hence in reduced , rather than increased adhesion strength . described above may be used alone , or any desired combi- The slurry for forming a negative - electrode active -mate nation of two or more thereof in any desired proportion may rial layer is generally produced by adding a binder , a be used . thickener, etc . to a negative - electrode material. The term The negative electrode in the nonaqueous - electrolyte sec - 65 " negative -electrode material” in this description means a ondary battery of this invention can be produced by any material including both a negative - electrode active material known method . Examples ofmethods for negative - electrode and a conductive material. US 9 ,853 , 326 B2 51 52 It is preferred that the content of the negative - electrode need . In the case of using a thickener, it is preferred to use active material in the negative - electrode material should be the thickener so that the content thereof in the negative generally 70 % by mass or higher , especially 75 % by mass or electrode active -material layer is in the range of generally higher , and be generally 97 % by mass or lower, especially from 0 . 5 % by mass to 5 % by mass . 95 % by mass or lower. The reasons for this are as follows. 5 The slurry for forming a negative - electrode active -mate In case where the content of the negative - electrode active rial layer is prepared by mixing the negative - electrode active material is too low , a secondary battery employing the material with a conductive material, a binder , and a thick resultant negative electrode tends to have an insufficient e ner according to need using an aqueous solvent or an capacity . In case where the content thereof is too high , the organic solvent as a dispersion medium . Water is generally relative content of the binder and other components is 10 used as the aqueous solvent . However , a solvent other than insufficient and this tends to result in insufficient strength of water, such as an alcohol, e . g . , ethanol, a cyclic amide , e . g . , the negative electrode obtained . When two or more nega - N -methylpyrrolidone , or the like, can be used in combina tive - electrode active materials are used in combination , this tion with water in a proportion of up to about 30 % by mass combination may be used so that the total amount of the based on the water. Examples of the organic solvent usually negative - electrode active materials satisfies that range . 15 include cyclic amides such as N -methylpyrrolidone , acyclic Examples of the conductive material for use in the nega - amides such as N , N - dimethylformamide and N , N -dimethy tive electrode include metallic materials such as copper and lacetamide , aromatic hydrocarbons such as anisole , toluene, nickel , and carbon materials such as graphites and carbon and xylene , and alcohols such as butanol and cyclohexanol . blacks . One of these materials may be used alone , or any Preferred of these are cyclic amides such as N -methylpyr desired combination of two or more thereof in any desired 20 rolidone and acyclic amides such as N , N - dimethylforma proportion may be used . In particular, use of a carbon mide and N , N -dimethylacetamide . Any one of such solvents material as the conductive material is preferred because the may be used alone , or any desired combination of two or carbon material functions also as an active material. It is more thereof in any desired proportion may be used . preferred that the content of the conductive material in the The viscosity of the slurry is not particularly limited so negative electrode should be generally 3 % by mass or 25 long as the slurry is applicable to a current collector. The higher , especially 5 % by mass or higher, and be generally slurry may be suitably prepared while changing the amount 30 % by mass or lower, especially 25 % by mass or lower of the solvent to be used , etc . so that the slurry is applicable . The reasons for this are as follows. In case where the content The slurry obtained is applied to the negative - electrode of the conductive material is too low , conductivity tends to current collector described above , and the coated collector is be insufficient. In case where the content thereof is too high , 30 dried and then pressed , whereby a negative - electrode active the relative content of the negative - electrode active material material layer is formed . Techniques for the application are and other components is insufficient and this tends to result not particularly limited , and a technique which itself is in decreases in battery capacity and strength . When two or known can be employed . Techniques for the drying also are more conductive materials are used in combination , this not particularly limited , and use can be made of a known combination may be used so that the total amount of the 35 technique such as, e . g ., natural drying , drying by heating , or conductive materials satisfies that range . vacuum drying . As the binder for the negative electrode , any desired The negative - electrode active material is used to produce binder can be used so long as it is safe for the solvent to be an electrode in the manner described above. The structure of used in electrode production and for the electrolyte . this electrode is not particularly limited . However, the Examples thereof include poly (vinylidene fluoride ), poly - 40 density of the active material present on the current collector tetrafluoroethylene, polyethylene, polypropylene, styrenel is preferably 1 gócm - or higher ,more preferably 1 . 2 g . cm - 3 butadiene rubbers, isoprene rubbers , butadiene rubbers, eth - or higher , especially preferably 1 . 3 g . cm - 3 or higher, and is ylene/ acrylic acid copolymers, and ethylene/ methacrylic preferably 2 gócm -3 or lower , more preferably 1 .9 g .cm - 3 or acid copolymers. One of these binders may be used alone , or lower, even more preferably 1 . 8 g cm * or lower , especially any desired combination of two or more thereof in any 45 preferably 1 . 7 g . cm or lower . When the density of the desired proportion may be used . It is preferred that the active material present on the current collector exceeds the content of the binder should be generally 0 . 5 parts by weight upper limit of that range , there are cases where particles of or larger , especially 1 part by weight or larger , and be the active material are destroyed and this causes an increase generally 10 parts by weight or smaller, especially 8 parts by in initial irreversible capacity and reduces the infiltration of weight or smaller , per 100 parts by weight of the negative - 50 the nonaqueous electrolyte into around the current collector / electrode material. The reasons for this are as follows. In active material interface, resulting in impaired high -current case where the content of the binder is too low , the resultant density charge / discharge characteristics. When the density electrode tends to have insufficient strength . In case where thereof is lower than the lower limit of that range , there are the content thereof is too high , the relative content of the cases where conductivity between particles of the active negative - electrode active material and other components is 55 material decreases, resulting in increased battery resistance insufficient and this tends to result in insufficient battery and reduced capacity per unit volume. capacity and insufficient conductivity . When two or more < 2 - 3 - 4 . Lithium -Containing Metal Composite Oxide Mate binders are used in combination , this combination may be rial, Constitution and Properties of Negative Electrode used so that the total amount of the binders satisfies that Employing Lithium - Containing Metal Composite Oxide ranges. 60 Material, and Method of Preparation Thereof > Examples of the thickener for use in the negative elec - The lithium -containing metal composite oxide material to trode include carboxymethyl cellulose , methyl cellulose , be used as a negative - electrode active material is not par hydroxymethyl cellulose , ethyl cellulose , poly ( vinyl alco - ticularly limited so long as the material is capable of hol) , oxidized starch , phosphorylated starch , and casein . One occluding / releasing lithium . However, a lithium -containing of these thickeners may be used alone , or any desired 65 composite metal oxide material containing titanium is pre combination of two or more thereof in any desired propor - ferred , and a composite oxide of lithium and titanium tion may be used . A thickener may be used according to (hereinafter abbreviated to " lithium - titanium composite US 9 ,853 , 326 B2 53 54 oxide” ) is more preferred . Namely , use of a lithium - titanium atmosphere pressure. The specific surface area determined composite oxide having a spinel structure is especially through this measurement is defined as the BET specific preferred because incorporation of this composite oxide into surface area of the lithium - titanium composite oxide in the a negative - electrode active material for nonaqueous -electro - invention . lyte secondary batteries is effective in considerably reducing 5 ( 2 ) Volume- Average Particle Diameter output resistance. The volume- average particle diameter ( secondary - par Also preferred are lithium - titanium composite oxides in which the lithium or titanium has been replaced by one or ticle diameter in the case where the primary particles have more other metallic elements, e . g ., at least one element aggregated to form secondary particles ) of the lithium selected from the group consisting of Na , K , Co , Al, Fe , Ti, 10 titanium composite oxide is defined as the volume- average Mg, Cr, Ga, Cu , Zn , and Nb. particle diameter (median diameter ) determined by the laser Such metal oxide preferably is a lithium - titanium com diffraction / scattering method . posite oxide represented by general formula ( 2 ) wherein The volume- average particle diameter of the lithium 0 .75xs1 . 5 , 1 . 5sys2 . 3 , and Oszs1 . 6 , because the structure titanium composite oxide is generally 0 . 1 um or larger , thereof is stable during lithium ion doping / undoping . 15 preferably 0 .5 um or larger , more preferably 0 . 7 um or larger, and is generally 50 um or smaller , preferably 40 um Li, Ti, M _04 or smaller , even more preferably 30 um or smaller, espe [ In general formula (2 ), M represents at least one element cially preferably 25 um or smaller . selected from the group consisting of Na, K , Co , Al, Fe , Ti, Volume- average particle diameter is determined by dis Mg, Cr, Ga, Cu , Zn , and Nb .] 20 persing the carbon powder in a 0 . 2 % by mass aqueous Of the compositions represented by general formula ( 2 ) , solution ( about 10 mL ) of poly ( oxyethylene (20 ) ) sorbitan structures represented by general formula ( 2 ) wherein monolaurate as a surfactant and examining the dispersion ( a ) 1 .25xs1 . 4 , 1. 5sys1 . 7 , and z = 0 with a laser diffraction / scattering type particle size distribu ( b ) 0 . 9sxs1 . 1 , 1 . 9sys2 . 1 , and z = 0 or tion analyzer (LA -700 , manufactured by HORIBA , Ltd . ) . ( c ) 0 .7sxs0 . 9 , 2 . 1 sys2 . 3 , and z = 0 The median diameter determined by this measurement is are especially preferred because they bring about a satisfac - defined as the volume- average particle diameter of the tory balance among battery performances . carbonaceous material in the invention . Especially preferred typical compositions of those com - When the volume- average particle diameter of the pounds are : Lis zTis 204 for ( a ), Li, Ti , O4 for ( b ) , and Lia lithium - titanium composite oxide is smaller than the lower 5 Ti 10 . for ( c ) . Preferred examples of the structure 30 limit of that range , there are cases where a large amount of wherein z 0 include Li4 /3T14 /3A11 /304 . a binder is necessary in electrode production and this results It is preferred that the lithium - titanium composite oxide in a decrease in battery capacity . When the volume- average for use as the negative - electrode active material in the particle diameter thereof exceeds the upper limit of that invention should satisfy at least one of the following features range, there are cases where such a composite oxide is ( 1 ) to ( 13 ) concerning properties, shape, etc ., besides the 35 undesirable from the standpoint of battery production requirements described above. Especially preferably , the because an uneven coating surface is apt to result when an composite oxide simultaneously satisfies two or more of the electrode plate is produced . following features . ( 3 ) Average Primary -Particle Diameter ( 1 ) BET Specific Surface Area In the case where the primary particles have aggregated to The BET specific surface area of the lithium - titanium 40 form secondary particles, the average primary - particle diam composite oxide for use as the negative - electrode active eter of the lithium - titanium composite oxide is generally material , as determined by the BET method , is preferably 0 .01 um or larger , preferably 0 . 05 um or larger , more 0 . 5 m². g - or larger , more preferably 0 . 7 m². g - or larger , preferably 0 . 1 um or larger, especially preferably 0 . 2 um or even more preferably 1. 0 m². g - or larger, especially pref- larger , and is generally 2 um or smaller, preferably 1 .6 um erably 1 . 5 m´. g - or larger , and is preferably 200 m´. g or 45 or smaller , more preferably 1 . 3 or smaller , especially pref smaller, more preferably 100 m². g - or smaller, even more erably 1 um or smaller . In case where the volume- average preferably 50 m². g - or smaller , especially preferably 25 primary - particle diameter thereof exceeds the upper limit of m . g or smaller . When the BET specific surface area thereof that range , spherical secondary particles are difficult to form is smaller than the lower limit of that range , there are cases and this adversely influences powder loading or results in a where use of this composite oxide as a negative - electrode 50 considerably reduced specific surface area . Theremay hence material results in a reduced reaction area available for be a high possibility that battery performances such as contactwith the nonaqueous electrolyte and in an increase in output characteristics might decrease . When the average output resistance . On the other hand , in case where the BET primary - particle diameter thereof is smaller than the lower specific surface area thereof exceeds the upper limit of that limit of that range , crystal growth is usually insufficient and , range , the proportion of surfaces and edge faces of crystals 55 hence, there are cases where use of this composite oxide of the titanium - containing metal oxide increases and this gives a secondary battery having reduced performances , causes crystal deformation . There are hence cases where e. g ., poor charge /discharge reversibility . irreversible capacity becomes not negligible and a preferred Primary - particle diameter is determined through an battery is difficult to obtain . examination with a scanning electron microscope (SEM ) . BET specific surface area is determined with a surface 60 Specifically, arbitrarily selected 50 primary -particle images area meter ( a fully automatic surface area measuring appa - in a photograph having a magnification capable of particle ratus manufactured by Ohukura Riken Co ., Ltd . ) by pre - observation , e . g ., 10 ,000 - 100 ,000 diameters , each are exam liminarily drying a sample at 350° C . for 15 minutes in a ined for the length of the longest segment of a horizontal line nitrogen stream and then measuring the specific surface area which extends across the primary -particle image from one thereof by the gas- flowing nitrogen adsorption BET one - 65 side to the other side of the boundary . These measured point method using a nitrogen /helium mixture gas precisely lengths are averaged , whereby the average value can be regulated so as to have a nitrogen pressure of 0 . 3 relative to determined . US 9 ,853 , 326 B2 55 56 ( 4 ) Shape higher , especially preferably 0 . 90 or higher. The higher the The shape of the particles of the lithium - titanium com - roundness , the more the high -current -density charge /dis posite oxide may be any of massive, polyhedral , spherical, charge characteristics are improved . Consequently , when the ellipsoidal , platy , acicular , columnar, and other shapes such roundness of the composite oxide is lower than the lower as those in common use . Preferred of these is one in which 5 limit of that range , there are cases where the negative the primary particles have aggregated to form secondary particles and these secondary particles have a spherical or electrode active material has reduced suitability for loading ellipsoidal shape . and interparticle resistance is increased , resulting in reduced In electrochemical elements , the active material in each short - time high - current- density charge / discharge character electrode usually expands / contracts with the charge / dis - 10 istics. charge of the element and , hence , deterioration is apt to Roundness is determined with a flow type particle image occur, such as active -material breakage and conduction path analyzer ( FPIA , manufactured by Sysmex Industrial Corp . ). breakage , due to the stress caused by the expansion / con About 0 .2 g of a sample is dispersed in a 0 . 2 % by mass traction . Because of this , an active material in which the aqueous solution (about 50 mL ) of poly ( oxyethylene ( 20 ) ) primary particles have aggregated to form secondary par - 15 sorbitan monolaurate as a surfactant, and an ultrasonic wave ticles is preferable to an active material composed of pri of 28 kHz is propagated to the dispersion for 1 minute at an mary particles only since the particles in the former active output of 60 W . Thereafter , particles having a particle material relieve the stress caused by expansion /contraction diameter in the range of 3 - 40 ism are examined with the to prevent deterioration . analyzer having a detection range set at 0 . 6 -400 um . The Furthermore , particles of a spherical or ellipsoidal shape 20 roundness determined through this measurement is defined are preferable to particles showing axial orientation , e . g . , as the roundness of the lithium - titanium composite oxide in platy ones , because the former particles are less apt to orient the invention . during electrode molding and hence this electrode is reduced ( 7 ) Aspect Ratio in expansion / contraction during charge/ discharge , and The aspect ratio of the lithium -titanium composite oxide because these particles are apt to be evenly mixed with a 25 is generally 1 or higher , and is generally 5 or lower, conductive material in electrode production . preferably 4 or lower, more preferably 3 or lower , especially ( 5 ) Tap Density preferably 2 or lower . When the aspect ratio thereof exceeds The tap density of the lithium -titanium composite oxide is the upper limit of that range , there are cases where this preferably 0 .05 g .cm - or higher ,more preferably 0 . 1 g . cm - 3 composite oxide causes streak lines in electrode plate for or higher, even more preferably 0 . 2 g . cm - or higher , espe - 30 mation and an even coating surface cannot be obtained , cially preferably 0 . 4 g . cm or higher , and is preferably 2 . 8 resulting in a decrease in short - time high -current - density g . cm - 3 or lower , more preferably 2 . 4 g . cm - > or lower, charge / discharge characteristics . Incidentally , the lower especially preferably 2 gócm - 3 or lower. In case where the limit of that range is a theoretical lower limit of the aspect tap density thereof is lower than the lower limit of that range , ratio of lithium - titanium composite oxides. this composite oxide , when used in a negative electrode , is 35 In determining aspect ratio , particles of the lithium less apt to have a high loading density and has a reduced titanium composite oxide are examined with a scanning interparticle contact area . There are hence cases where electron microscope with enlargement . Fifty are arbitrarily interparticle resistance increases and output resistance selected from composite - oxide particles fixed to an edge increases . On the other hand , in case where the tap density face of a metal having a thickness of 50 um or smaller, and thereof exceeds the upper limit of that range , the electrode 40 each particle is examined in a three -dimensional manner has too small an amount of interparticle interstices and a while rotating or inclining the stage to which the sample is reduced amount of channels for the nonaqueous electrolyte . fixed . In this examination , the length of the longest axis A of There are hence cases where output resistance increases . each particle and the length of the shortest axis B perpen The tap density of a sample is determined by dropping the dicular to that axis are measured , and the average of the A / B sample through a sieve having an opening size of 300 um 45 values is determined . The aspect ratio ( A / B ) determined into a 20 cm tapping cell to fill the cell with the sample up through this measurement is defined as the aspect ratio of the to the brim , subsequently conducting tapping operations lithium - titanium composite oxide in the invention . 1 ,000 times over a stroke length of 10 mm using a powder ( 8 ) Processes for Producing Negative - Electrode Active densimeter ( e . g . , Tap Denser, manufactured by Seishin Material Enterprise Co . , Ltd . ), and calculating a density from the 50 Processes for producing the lithium - titanium composite resultant volume of the sample and the weight thereof. The oxide are not particularly limited unless they depart from the tap density calculated through this measurement is defined spirit of the invention . Examples thereof include several as the tap density of the lithium - titanium composite oxide in processes , and processes in general use for producing inor the invention . ganic compounds may be employed . ( 6 ) Roundness 55 Examples thereof include a method in which a titanium When the lithium - titanium composite oxide is examined source , e . g ., titanium oxide , is evenly mixed with a lithium for roundness as an index to the degree of sphericity thereof, source , e . g . , LiOH , Li, CO3, or LiNO3, and optionally with the roundness thereof is preferably within the range shown a source of other element( s ) and this mixture is burned at a below . Roundness is defined by “ Roundness = ( length of high temperature to obtain the active material. periphery of equivalent circle having the same area as 60 Especially for producing spherical or ellipsoidal active projected particle shape )/ (actual length of periphery of pro - materials , various techniques are usable . Examples thereof jected particle shape) ” . When a particle has a roundness of include : a method which comprises dissolving or pulveriz 1 , this particle theoretically is a true sphere . ing/ dispersing a titanium source , e . g ., titanium oxide, The closer to 1 the roundness of the lithium - titanium optionally together with a source of other element( s ) in a composite oxide, the more the particles thereof are desirable . 65 solvent, e. g ., water , regulating the pH of the solution or The roundness of the composite oxide is generally 0 . 10 or dispersion with stirring to produce a spherical precursor, higher, preferably 0 .80 or higher, more preferably 0 .85 or recovering and optionally drying the precursor, subse US 9 ,853 , 326 B2 57 58 quently adding thereto a lithium source, e . g. , LiOH , Li_ C03 , rolling process, and an electrolytic copper foil, which is or LiNO3, and burning the mixture at a high temperature to produced by the electrolytic process . Either of these can be obtain the active material. used as a current collector. Another example is a method which comprises dissolving In the case of a copper foil having a thickness smaller than or pulverizing /dispersing a titanium source , e . g . , titanium 5 25 use can be made of a copper alloy ( e . g . , phosphor bronze , oxide, optionally together with a source of other element( s ) titanium - copper , Corson alloy , or Cu .Cr . Zr alloy ) having a in a solvent, e . g . , water, drying and forming the solution or higher strength than pure copper. Furthermore , an aluminum dispersion with a spray dryer or the like to obtain a spherical foil can be advantageously used because it has a low specific or ellipsoidal precursor , adding thereto a lithium source , e . g ., gravity and , hence , use of the foil as a current collector can LiOH , Li_ C03, or LiNO3, and burning the mixture at a high 10 reduce the weight of the battery . temperature to obtain the active material. The current collector comprising a copper foil produced Still another example is a method which comprises dis - by the rolling process is less apt to crack even when the solving or pulverizing / dispersing a titanium source , e . g . , negative electrode is rolled tightly or rolled at an acute titanium oxide, together with a lithium source, e . g . , LiOH , angle , because the copper crystals are oriented in the rolling Li, CO2, or LiNOz, and optionally with a source of other 15 direction . This current collector can be advantageously used element( s ) in a solvent , e .g . , water , drying and forming the in small cylindrical batteries. solution or dispersion with a spray dryer or the like to obtain The electrolytic copper foil is obtained by immersing a a spherical or ellipsoidal precursor, and burning the precur - metallic drum in a nonaqueous electrolyte containing copper sor at a high temperature to obtain the active material. ions dissolved therein , causing current to flow through the In those steps , one or more of elements other than Ti , such 20 system while rotating the drum to thereby deposit copper on as, e . g . , A1, Mn , Ti, V , Cr, Mn, Fe , Co , Li, Ni, Cu , Zn , Mg, the drum surface , and peeling the copper deposit from the Ga, Zr, C , Si, Sn , and Ag, can be caused to be present in the drum . Copper may be deposited on a surface of the rolled titanium - containing metal oxide structure and /or present so copper foil by the electrolytic process . One or each side of as be in contact with the titanium - containing oxide . The such a copper foil may have undergone a surface -roughen incorporation of such elements can be used for regulating 25 ing treatment or a surface treatment ( e . g . , a chromate treat the operating voltage and capacity of the battery . ment in a thickness of from several nanometers to about 1 ( 9 ) Electrode Production um or a priming treatment with titanium ) . Any known method can be used for electrode production . The current collector base is desired to further have the For example , a binder and a solvent are added to a negative - following properties . electrode active material optionally together with a thick - 30 ( 10 - 1 ) Average Surface Roughness (Ra ) ener, conductive material, filler, etc . to obtain a slurry and The average surface roughness ( Ra ) of that side of the this slurry is applied to a current collector and dried current collector base on which a thin active -material film is Thereafter , the coated current collector is pressed , whereby to be formed , as determined by the method provided for in an electrode can be formed . JIS B 0601 - 1994 , is not particularly limited . However, the The thickness of the negative- electrode active -material 35 average surface roughness thereof is generally 0 .01 um or layer per one side in the stage just before the step of injecting higher, preferably 0 .03 um or higher , and is generally 1 .5 um a nonaqueous electrolyte in battery fabrication is generally or lower, preferably 1 . 3 um or lower, more preferably 1 . 0 um 15 um or larger, preferably 20 um or larger , more preferably or lower . 30 um or larger. The upper limit thereof desirably is 150 um T his is because when the average surface roughness (Ra ) or smaller , preferably 120 um or smaller , more preferably 40 of the current collector base is within that range , satisfactory 100 um or smaller. When the thickness thereof is larger than charge /discharge cycle characteristics can be expected . In the upper limit of that range , a nonaqueous electrolyte is less addition , the area of the interface between the base and a thin apt to infiltrate into around the interface of the current active -material film is increased and adhesion to the thin collector and , hence, there are cases where high - current- negative - electrode active -material film is improved . The density charge / discharge characteristics decrease . When the 45 upper limit of the average surface roughness (Ra ) thereof is thickness thereof is smaller than the lower limit of that not particularly limited . However , a current collector base range, the proportion by volume of the current collector to having an average surface roughness (Ra ) of 1 . 5 ul or lower the negative - electrode active material increases and there are is usually employed because a foil having a practical thick cases where battery capacity decreases. The negative - elec - ness for batteries and having an Ra exceeding 1 . 5 um is trode active material may be roller - pressed to obtain a sheet 50 generally difficult to procure . electrode, or may be subjected to compression molding to ( 10 - 2 ) Tensile Strength obtain a pellet electrode . Tensile strength is a quotient obtained by dividing the ( 10 ) Current Collector maximum tensile force required before test piece breakage As the current collector for holding the negative -electrode by the sectional area of the test piece. In the invention , the active material, a known one can be used at will. Examples 55 tensile strength is determined through a measurement con of the current collector for the negative electrode include ducted with the same apparatus and by the same method as metallic materials such as copper, nickel , stainless steel, and those described in JIS Z 2241 (Method of Metallic -Material nickel- plated steel . Copper is especially preferred of these Tensile Test) . from the standpoints of processability and cost. The tensile strength of the current collector base is not In the case where the current collector is a metallic 60 particularly limited . However , it is generally 50 N ·mm - 2 or material , examples of the shape of the current collector higher, preferably 100 N ·mm - 2 or higher, more preferably include metal foils , metal cylinders , metal coils , metal 150 N ·mm - 2 or higher . The higher the tensile strength , the plates, thin metal films, expanded metals , punching metals , more the current collector base is preferred . However, it is and metal foams. Preferred of these are metal foil films desirable that the tensile strength thereof should be generally including copper (Cu ) and /or aluminum (Al ) . More pre - 65 1 ,000 N ·mm - 2 or lower from the standpoint of industrial ferred are copper foils and aluminum foils . Even more availability . A current collector base having a high tensile preferred are a rolled copper foil, which is produced by the strength can be inhibited from cracking with the expansion / US 9 ,853 , 326 B2 59 60 contraction of the thin active -material film which occur upon electrode active material is weak and the active material charge / discharge . With this current collector base , satisfac sheds from the electrode . When the density thereof is lower tory cycle characteristics can be obtained . than the lower limit of that range, there are cases where ( 10 - 3 ) 0 . 2 % Proof Stress electrical conductivity among particles of the negative The term 0 . 2 % proof stress means the degree of load 5 electrode active material decreases and this increases battery necessary for imparting a plastic ( permanent ) deformation of resistance . 0 . 2 % . Namely , it means that application of that degree of (13 ) Binder load and subsequent removal thereof result in a 0 . 2 % The binder for binding the negative - electrode active mate deformation . The 0 . 2 % proof stress is determined through a rial is not particularly limited so long as it is stable to the measurement conducted with the same apparatus and by the 10 nonaqueous electrolyte and to the solvent to be used for same method as for tensile strength . electrode production . The 0 . 2 % proof stress of the current collector base is not Examples thereof include resinous polymers such as particularly limited . However , the 0 . 2 % proof stress thereof polyethylene, polypropylene, poly ( ethylene terephthalate ) , is generally 30 N ·mm - 2 or higher, preferably 100 N ·mm - 2 or poly (methyl methacrylate ), polyimides , aromatic poly higher, especially preferably 150 N /mm² or higher. The 15 amides, cellulose , and nitrocellulose ; rubbery polymers such higher the 0 . 2 % proof stress , the more the current collector as SBR ( styrene /butadiene rubbers ), isoprene rubbers , buta base is preferred . However, the 0 . 2 % proof stress thereof is diene rubbers , fluororubbers , NBR ( acrylonitrile /butadiene generally desirably 900 N ·mm - 2 or lower from the stand rubbers ), and ethylene/ propylene rubbers ; styrene / butadi point of industrial availability . A current collector base ene/ styrene block copolymers or products of hydrogenation having a high 0 . 2 % proof stress can be inhibited from 20 thereof ; thermoplastic elastomeric polymers such as EPDM plastically deforming with the expansion /contraction of the (ethylene / propylene/ diene terpolymers ), styrenelethylene / thin active -material film which occur upon charge /dis butadiene/ styrene copolymers , and styrene / isoprene / styrene charge. With this current collector base , satisfactory cycle block copolymers and products of hydrogenation thereof; characteristics can be obtained . flexible resinous polymers such as syndiotactic - 1, 2 -polyb ( 10 - 4 ) Thickness of Current Collector 25 utadiene , poly (vinyl acetate ), ethylene /vinyl acetate copoly The current collector may have any desired thickness . mers , and propylene/ a -olefin copolymers ; fluorochemical However, the thickness thereof is generally 1 um or larger, polymers such as poly (vinylidene fluoride ) , polytetrafluoro preferably 3 um or larger, more preferably 5 um or larger, ethylene, fluorinated poly (vinylidene fluoride ), and polytet and is generally 1 mm or smaller, preferably 100 um or rafluoroethylene / ethylene copolymers ; and polymer compo smaller , more preferably 50 um or smaller . In case where the 30 sitions having the property of conducting alkali metal ions current collector is thinner than 1 um , this collector has (especially lithium ions ). One of these may be used alone , or reduced strength and there are hence cases where coating is any desired combination of two or more thereof in any difficult . When the current collector is thicker than 100 um , desired proportion may be used . there are cases where this collector deforms an electrode The kind of the solvent to be used for forming a slurry is shape , e . g ., a rolled form . The current collector may be in a 35 not particularly limited so long as it is a solvent in which the mesh form . negative -electrode active material and binder and the thick ( 11 ) Thickness Ratio Between Current Collector and Active ener and conductive material which are optionally used Material Layer according to need can be dissolved or dispersed . Either an The thickness ratio between the current collector and the aqueous solvent or an organic solvent may be used . active -material layer is not particularly limited . However, 40 Examples of the aqueous solvent include water and alco the value of “ thickness of the active -material layer on one hols . Examples of the organic solvent include N -methylpyr side just before impregnation with the nonaqueous electro - rolidone (NMP ) , dimethylformamide , dimethylacetamide , lyte) / ( thickness of the current collector )” is generally 150 or methyl ethyl ketone, cyclohexanone, methyl acetate , methyl smaller, preferably 20 or smaller, more preferably 10 or acrylate , diethyltriamine , N , N -dimethylaminopropylamine , smaller, and is generally 0 . 1 or larger, preferably 0 . 4 or 45 tetrahydrofuran ( THF) , toluene, acetone , diethyl ether , dim larger , more preferably 1 or larger. When the thickness ratio ethylacetamide , hexamethylphosphoramide , dimethyl sul between the current collector and the negative - electrode foxide, benzene, xylene, quinoline, pyridine , methylnaph active -material layer exceeds the upper limit of that range , thalene , and hexane . Especially when an aqueous solvent is there are cases where this current collector heats up due to used , a dispersant or the like is added in combination with Joule ' s heat during high -current - density charge /discharge . 50 the thickener described above to prepare a slurry using a When that ratio decreases beyond the lower limit of that latex of, e . g ., SBR . One of such ingredients may be used range , the proportion by volume of the current collector to alone , or any desired combination of two or more thereof in the negative - electrode active material increases and this may any desired proportion may be used . reduce the capacity of the battery . The proportion of the binder to the negative -electrode ( 12 ) Electrode Density 55 active material is generally 0 . 1 % by mass or higher, pref When the negative - electrode active material is used to erably 0 . 5 % by mass or higher, more preferably 0 .6 % by form an electrode, the electrode structure is not particularly mass or higher, and is generally 20 % by mass or lower, limited . However, the density of the active material present preferably 15 % by mass or lower, more preferably 10 % by on the current collector is preferably 1 . 0 g . cm or higher, mass or lower , especially preferably 8 % by mass or lower . more preferably 1 . 2 g . cm or higher , even more preferably 60 In case where the proportion of the binder to the negative 1 . 3 g cm3 or higher , especially preferably 1 . 5 gócm - or electrode active material exceeds the upper limit of that higher , and is preferably 3 g . cm - or lower , more preferably range , the proportion ofthe binder which does not contribute 2 .5 g .cm3 or lower , even more preferably 2. 2 g .cm - or to battery capacity increases and this may lead to a decrease lower, especially preferably 2 g .cm - 3 or lower. When the in battery capacity . When the binder proportion is small than density of the active material present on the current collector 65 the lower limit , there are cases where the negative electrode exceeds the upper limit of that range , there are cases where has reduced strength and this is undesirable from the stand bonding between the current collector and the negative - point of battery fabrication step . US 9 ,853 , 326 B2 62 Especially when the binder includes a rubbery polymer compounds include iron phosphate compounds such as represented by SBR as the main component, the proportion LiFePO4, LizFe , ( PO4) 3 and LiFeP 07, cobalt phosphate of this binder to the active material is generally 0 . 1 % by compounds such as LiCoPO4, and ones formed by partly mass or higher, preferably 0 . 5 % by mass or higher, more replacing the transition metal atom ( s ) as a main component preferably 0 . 6 % by mass or higher , and is generally 5 % by 5 of these lithium -transition metal/ phosphoric acid com mass or lower , preferably 3 % by mass or lower, more pounds by one or more other metals , e . g . , A1, Ti, V , Cr, Mn , preferably 2 % by mass or lower . Fe, Co, Li, Ni, Cu , Zn , Mg, Ga, Zr, Nb , Si, etc . In the case where the binder includes a fluorochemical ( 2 ) Surface Coating polymer represented by poly ( vinylidene fluoride ) as the Use may be made of a material including any of those main component, the proportion of this binder to the active 10 positive - electrode active materials and , adherent to the sur material is 1 % by mass or higher , preferably 2 % by mass or face thereof, a substance (hereinafter abbreviated to " sur higher, more preferably 3 % by mass or higher, and is face -adherent substance ” ) having a composition different generally 15 % by mass or lower , preferably 10 % by mass or from that of the substance constituting the core positive lower ,more preferably 8 % by mass or lower . electrode active material. Examples of the surface -adherent A thickener is used generally for the purpose of regulating 15 substance include oxides such as aluminum oxide , silicon the slurry viscosity . The thickener is not particularly limited oxide , titanium oxide , zirconium oxide , magnesium oxide , Examples thereof include carboxymethyl cellulose, methyl calcium oxide, boron oxide , antimony oxide , and bismuth cellulose , hydroxymethyl cellulose , ethyl cellulose, poly oxide , sulfates such as lithium sulfate , sodium sulfate , ( vinyl alcohol) , oxidized starch , phosphorylated starch , potassium sulfate , magnesium sulfate, calcium sulfate, and casein , and salts of these . One of these thickeners may be 20 aluminum sulfate , and carbonates such as lithium carbonate , used alone , or any desired combination of two or more calcium carbonate , and magnesium carbonate and the like . thereof in any desired proportion may be used . Those surface - adherent substances each can be adhered to In the case where such a thickener is further added , the the surface of a positive - electrode active material , for proportion of the thickener to the negative - electrode active example , by: a method in which the substance is dissolved material is generally 0 . 1 % by mass or higher , preferably 25 or suspended in a solvent and this solution or suspension is 0 . 5 % by mass or higher , more preferably 0 . 6 % by mass or infiltrated into a positive - electrode active material and then higher , and is generally 5 % by mass or lower , preferably 3 % dried ; a method in which a precursor for the surface by mass or lower , more preferably 2 % by mass or lower. adherent substance is dissolved or suspended in a solvent When the proportion thereof is lower than the lower limit of and this solution or suspension is infiltrated into a positive that range , there are cases where applicability decreases 30 electrode active material and then heated or otherwise considerably . Proportions thereof exceeding the upper limit treated to react the precursor ; or a method in which the of that range result in a reduced proportion of the active substance is added to a precursor for a positive - electrode material in the negative - electrode active -material layer , and active material and heat - treated together with the precursor. this may pose a problem that battery capacity decreases and The mass of the surface -adherent substance adherent to a problem that resistance among the particles of the nega - 35 the surface of the positive - electrode active material is gen tive -electrode active material increases. erally 0 . 1 ppm or larger , preferably 1 ppm or larger, more < 2 - 4 . Positive Electrode > preferably 10 ppm or larger , in terms of mass ppm of the The positive electrode for use in the nonaqueous - electro positive - electrode active material. The amount thereof is lyte secondary battery of this invention is explained below . generally 20 % or smaller, preferably 10 % or smaller , more < 2 -4 - 1 . Positive - Electrode Active Material 40 preferably 5 % or smaller , based on the mass of the positive Positive - electrode active materials usable in the positive electrode active material . electrode are explained below . The surface -adherent substance serves to inhibit the non ( 1 ) Composition aqueous electrolyte from undergoing an oxidation reaction The positive - electrode active materials are not particu on the surface of the positive - electrode active material, larly limited so long as these are capable of electrochemi- 45 whereby the battery life can be improved . However , in case cally occluding /releasing lithium ions . For example , how where the amount of the substance adhered is smaller than ever , a substance containing lithium and at least one the lower limit of that range, that effect is not sufficiently transition metal is preferred . Examples thereof include produced . On the other hand , amounts thereof exceeding the lithium - transition metal composite oxides and lithium - con - upper limit of that range may result in an increase in taining transition metal/ phosphoric acid compounds . 50 resistance because the surface - adherent substance inhibits The transition metal in the lithium - transition metal com - the occlusion / release of lithium ions. Consequently , that posite oxides preferably is V , Ti, Cr, Mn , Fe , Co , Ni, Cu , or range is preferred . the like . Specific examples of the composite oxides include ( 3 ) Shape lithium - cobalt composite oxides such as LiCo02, lithium The shape of the particles of the positive -electrode active nickel composite oxides such as LiNiO2, lithium -manganese 55 material may be any of massive , polyhedral, spherical, composite oxides such as LiMnO2, LiMn204, and Li, Mn04 , ellipsoidal, platy , acicular , columnar, and other shapes such and ones formed by partly replacing the transition metal as those in common use . Preferred of these is one in which atom ( s ) as a main component of these lithium - transition the primary particles have aggregated to form secondary metal composite oxides by one or more other metals, e . g ., particles and these secondary particles have a spherical or A1, Ti, V , Cr, Mn , Fe, Co, Li, Ni, Cu , Zn , Mg, Ga , Zr, Si, etc . 60 ellipsoidal shape . Examples of such compounds formed by replacement The reasons for that are as follows. In electrochemical include LiNi0 .5Mn0 . 502, LiNi0 .85CO0 . 10A10 .0502 , elements , the active material in each electrode usually LiNi0. 33 C0033Mn0 .3302 ; LiMn, .8A10 . 204 and expands/ contracts with the charge / discharge of the element LiMn? sNi, 504, etc . and , hence , deterioration is apt to occur, such as active The transition metal in the lithium - containing transition 65 material breakage and conduction path breakage, due to the metal/ phosphoric acid compounds preferably is V , Ti, Cr, stress caused by the expansion / contraction . Consequently , a Mn, Fe, Co , Ni, Cu , or the like. Specific examples of the positive- electrode active material in which the primary US 9 ,853 , 326 B2 63 64 particles have aggregated to form secondary particles is ducing a positive electrode for batteries , i .e ., when the active preferable to an active material composed of primary par material and other ingredients including a conductive mate ticles only since the particles in the former active material rial and a binder are slurried with a solvent and this slurry relieve the stress caused by expansion / contraction to prevent is applied in a thin - film form , pose a problem , for example , deterioration . 5 that streak lines generate . Furthermore, particles of a spherical or ellipsoidal shape It is possible to further improve loading in positive are preferable to particles showing axial orientation , e . g ., electrode production by mixing two or more positive -elec platy ones , because the former particles are less apt to orient trode active materials differing in median diameter d50 . during electrodemolding and hence this electrode is reduced In determining median diameter d50 , a 0 . 1 % by mass in expansion / contraction during charge/ discharge , and 10 aqueous solution of sodium hexametaphosphate is used as a because these particles are apt to be evenly mixed with a dispersion medium . LA - 920 , manufactured by HORIBA , conductive material in electrode production . Ltd ., is used as a particle size distribution analyzer to ( 4 ) Tap Density conduct a five -minute ultrasonic dispersing treatment, The tap density of the positive - electrode active material is before the particles are examined at a measuring refractive generally 1 . 3 gocm -> or higher, preferably 1 .5 g. cm or 15 index set at 1. 24 . higher , more preferably 1 . 6 g .cm " or higher , especially (6 ) Average Primary -Particle Diameter preferably 1 . 7 g . cm - or higher , and is generally 2 . 5 gocm3 In the case where the primary particles have aggregated to or lower, preferably 2 . 4 g•cm - or lower . form secondary particles , the average primary - particle diam By using a metal composite oxide powder having a high e ter of this positive - electrode active material is generally tap density , a positive - electrode active -material layer having 20 0 .01 um or larger , preferably 0 .05 um or larger, more a high density can be formed . Consequently , when the tap preferably 0 . 08 um or larger, especially preferably 0 . 1 um or density of the positive - electrode active material is lower larger, and is generally 3 um or smaller, preferably 2 um or than the lower limit of that range , not only it is necessary to smaller , more preferably 1 um or smaller , especially pref use a larger amount of a dispersion medium and larger erably 0 .6 um or smaller. The reasons for this are as follows. amounts of a conductive material and a binder in forming a 25 In case where the average primary -particle diameter thereof positive - electrode active -material layer. There are hence exceeds the upper limit of that range, spherical secondary cases where the loading of the positive - electrode active particles are difficult to form and this adversely influences material in the positive - electrode active -material layer is powder loading or results in a considerably reduced specific limited , resulting in a limited battery capacity . The higher surface area . There may hence be a high possibility that the tap density , the more the positive - electrode active mate - 30 battery performances such as output characteristics might rial is generally preferred . There is no particular upper limit decrease . When the average primary - particle diameter on the tap density. However, when the tap density thereof is thereof is smaller than the lower limit of that range , crystal lower than that range , there are cases where the diffusion of growth is usually insufficient and , hence , there are cases lithium ions in the positive -electrode active- material layer where use of this positive - electrode active material gives a through the nonaqueous electrolyte as a medium becomes a 35 secondary battery having reduced performances, e . g ., poor rate - determining stage and this is apt to reduce load char - charge /discharge reversibility . acteristics. Average primary - particle diameter is determined through The tap density of a sample is determined by dropping the an examination with a scanning electron microscope (SEM ) . sample through a sieve having an opening size of 300 um Specifically , arbitrarily selected 50 primary -particle images into a 20 cm tapping cell to fill the capacity of the cell with 40 in a photograph having a magnification of 10, 000 diameters the sample, subsequently conducting tapping operations each are examined for the length of the longest segment of 1, 000 times over a stroke length of 10 mm using a powder a horizontal line which extends across the primary - particle densimeter ( e . g . , Tap Denser, manufactured by Seishin image from one side to the other side of the boundary . These Enterprise Co ., Ltd . ), and determining a density from the measured lengths are averaged , whereby the average value resultant volume of the sample and the weight thereof. The 45 can be determined . tap density determined through this measurement is defined ( 7 ) BET Specific Surface Area as the tap density of the positive- electrode active material in The BET specific surface area of the positive -electrode the invention . activematerial , in terms of the value of specific surface area ( 5 ) Median Diameter d50 as determined by the BET method , is generally 0 . 2 m². g - 1 Themedian diameter d50 ( secondary -particle diameter in 50 or larger, preferably 0 . 3 m². g - or larger, more preferably 0 . 4 the case where the primary particles have aggregated to form m´. g - or larger, and is generally 4 . 0 m g - or smaller, secondary particles ) of the particles of the positive- electrode preferably 2 . 5 m². g - or smaller ,more preferably 1 . 5 m². g - 1 active material can be determined also with a laser diffrac or smaller . In case where the BET specific surface area tion / scattering type particle size distribution analyzer . thereof is smaller than the lower limit of that range , battery The median diameter d50 thereof is generally 0 . 1 um or 55 performances are apt to decrease . In case where the BET larger , preferably 0 . 5 um or larger, more preferably 1 um or specific surface area thereof exceeds the upper limit of that larger , especially preferably 3 um or larger, and is generally range , a high tap density is difficult to obtain and there are 20 um or smaller, preferably 18 ul or smaller , more prefer - cases where applicability in forming a positive - electrode ably 16 um or smaller , especially preferably 15 um or active - material layer is poor. smaller. When the median diameter d50 thereof is smaller 60 BET specific surface area is measured with a surface area than the lower limit of that range , there are cases where a meter ( a fully automatic surface area measuring apparatus product having a high bulk density cannot be obtained . manufactured by Ohukura Riken Co . , Ltd . ) . The specific When the median diameter thereof exceeds the upper limit surface area is determined by preliminarily drying a sample of that range , lithium diffusion in the individual particles at 150° C . for 30 minutes in a nitrogen stream and then requires a longer time and this results in a decrease in battery 65 measuring the specific surface area thereof by the gas performance . In addition , there are cases where such posi- flowing nitrogen adsorption BET one - point method using a tive - electrode active -material particles , when used in pro - nitrogen /helium mixture gas precisely regulated so as to US 9 ,853 , 326 B2 65 66 have a nitrogen pressure of 0 . 3 relative to atmosphere active -material layer is lower than the lower limit of that pressure . The specific surface area determined through this range , there are cases where an insufficient electrical capac measurement is defined as the BET specific surface area of ity results . When the content thereof exceeds the upper limit the positive - electrode active material in the invention . of that range , there are cases where the positive electrode has ( 8 ) Processes for Producing Positive -Electrode Active Mate - 5 insufficient strength . One positive - electrode active -material rial powder may be used alone in the invention , or any desired Processes for producing positive- electrode active materi combination of two or more positive - electrode active mate als are not particularly limited unless the processes depart rials differing in composition or powder properties may be from the spirit of the invention . Examples thereof include used in any desired proportion . several processes . Techniques which are in general use for 10 ( 2 ) Conductive Material producing inorganic compounds may be employed . As the conductive material, a known conductive material Especially for producing spherical or ellipsoidal active can be used at will . Examples thereof include metallic materials , various techniques are usable . Examples thereof materials such as copper and nickel; graphites such as include: a method which comprises dissolving or pulveriz natural graphites and artificial graphites; carbon blacks such ing / dispersing a transition metal source , e . g . , a transition 15 as acetylene black ; and carbon materials such as amorphous metal nitrate or sulfate , optionally together with a source of carbon , e . g ., needle coke . One of these materials may be other element( s ) in a solvent, e . g . , water , regulating the pH used alone , or any desired combination of two or more of the solution or dispersion with stirring to produce a thereof in any desired proportion may be used . spherical precursor , recovering and optionally drying the The conductive material may be used so that it is incor precursor, subsequently adding thereto a lithium source , e . g ., 20 porated in the positive - electrode active -material layer in an LiOH , Li , CO2, or LiNO , , and burning the mixture at a high amount of generally 0 .01 % by mass or larger, preferably temperature to obtain the active material. 0 . 1 % by mass or larger , more preferably 1 % by mass or Another example is a method which comprises dissolving larger, and of generally 50 % by mass or lower , preferably or pulverizing/ dispersing a transition metal source, e . g . , a 30 % by mass or lower, more preferably 15 % by mass or transition metal nitrate , sulfate , hydroxide , or oxide , option - 25 lower. When the content thereof is lower than the lower limit ally together with a source of other element ( s ) in a solvent, of that range , there are cases where electrical conductivity e . g . , water, drying and forming the solution or dispersion becomes insufficient. Conversely , when the content thereof with a spray dryer or the like to obtain a spherical or exceeds the upper limit of that range , there are cases where ellipsoidal precursor, adding thereto a lithium source , e . g ., battery capacity decreases . LiOH , Li ,CO2 , or LiNO , , and burning the mixture at a high 30 (3 ) Binder temperature to obtain the active material. The binder to be used for producing the positive - electrode Still another example is a method which comprises dis - active -material layer is not particularly limited so long as the solving or pulverizing / dispersing a transition metal source , binder is stable to the nonaqueous electrolyte and to the e . g ., a transition metal nitrate , sulfate , hydroxide , or oxide, solvent to be used for electrode production . together with a lithium source , e . g ., LiOH , Li, COz, or 35 In the case where the layer is to be formed through coating LiNO3, and optionally with a source of other element( s ) in fluid application , any binder may be used so long as it is a a solvent, e . g ., water, drying and forming the solution or material which is soluble or dispersible in the liquid medium dispersion with a spray dryer or the like to obtain a spherical for use in electrode production . Examples thereof include or ellipsoidal precursor, and burning the precursor at a high resinous polymers such as polyethylene , polypropylene , temperature to obtain the active material. 40 poly ( ethylene terephthalate ) , poly (methyl methacrylate ) , < 2 - 4 - 2 . Electrode Structure and Production Process aromatic polyamides , cellulose , and nitrocellulose ; rubbery The constitution of the positive electrode to be used in this polymers such as SBR ( styrene /butadiene rubbers ) , NBR invention and a process for producing the electrode will be ( acrylonitrile /butadiene rubbers ) , fluororubbers, isoprene described below . rubbers, butadiene rubbers , and ethylene / propylene rubbers ; ( 1 ) Process for Producing Positive Electrode 45 thermoplastic elastomeric polymers such as styrene/ butadi The positive electrode is produced by forming a positive ene / styrene block copolymers or products of hydrogenation electrode active- material layer including particles of a posi - thereof, EPDM ( ethylene/ propylene / diene terpolymers ), sty tive - electrode active material and a binder on a current renelethylene /butadiene / ethylene copolymers , and styrenel collector. The production of the positive electrode with a isoprene/ styrene block copolymers or products of hydroge positive -electrode active material can be conducted in an 50 nation thereof; flexible resinous polymers such as ordinary manner . Namely , a positive - electrode active mate - syndiotactic - 1 , 2 -polybutadiene , poly ( vinyl acetate ), ethyl rial and a binder are mixed together by a dry process ene/ vinyl acetate copolymers , and propylenela -olefin copo optionally together with a conductive material, thickener , lymers ; fluorochemical polymers such as poly ( vinylidene etc . and this mixture is formed into a sheet and press -bonded fluoride ) (PVDF ) , polytetrafluoroethylene , fluorinated poly to a positive -electrode current collector. Alternatively , those 55 (vinylidene fluoride ), and polytetrafluoroethylene /ethylene materials are dissolved or dispersed in a liquid medium to copolymers ; and polymer compositions having the property obtain a slurry and this slurry is applied to a positive of conducting alkali metal ions ( especially lithium ions ) . electrode current collector and dried . Thus , a positive - One of these substances may be used alone , or any desired electrode active -material layer is formed on the current combination of two or more thereof in any desired propor collector, whereby the positive electrode can be obtained . 60 tion may be used The content of the positive - electrode active material in the The proportion of the binder in the positive -electrode positive - electrode active -material layer is generally 10 % by active -material layer is generally 0 . 1 % by mass or higher, mass or higher, preferably 30 % by mass or higher , especially preferably 1 % by mass or higher, more preferably 3 % by preferably 50 % by mass or higher , and is generally 99 . 9 % by mass or higher, and is generally 80 % by mass or lower, mass or lower, preferably 99 % by mass or lower. The 65 preferably 60 % by mass or lower , more preferably 40 % by reasons for this are as follows. When the content of the mass or lower, especially preferably 10 % by mass or lower . positive -electrode active material in the positive -electrode When the proportion of the binder is lower than the lower US 9 ,853 , 326 B2 67 68 limit of that range, there are cases where the positive - g .cm - 3 or lower , more preferably 3 . 5 g. cm - 3 or lower, electrode active material cannot be sufficiently held and the especially preferably 3 g .cm - 3 or lower . When the density of positive electrode has insufficient mechanical strength to the positive- electrode active -material layer exceeds the impair battery performances such as cycle characteristics . upper limit of that range , the infiltration of a nonaqueous When the proportion thereof is higher than the upper limit of 5 electrolyte into around the current collector /active material that range , there are cases where such high proportions lead interface becomes insufficient and there are cases where to a decrease in battery capacity or conductivity . charge /discharge characteristics especially at a high current ( 4 ) Liquid Medium density decrease . When the density thereof is lower than the The kind of the liquid medium to be used for forming a lower limit of that range , there are cases where electrical slurry is not particularly limited so long as it is a solvent in 10 conductivity among the active -material particles decreases which the positive - electrode active material, conductive to increase battery resistance . material, and binder and a thickener, which is used accord - ( 7 ) Current Collector ing to need , can be dissolved or dispersed . Either an aqueous The material of the positive - electrode current collector is solvent or an organic solvent may be used . not particularly limited , and a known one can be used at will . Examples of the aqueous medium include water and 15 Examples thereof include metallic materials such as alumi mixed solvents including an alcohol and water. Examples of num , stainless steel, nickel- plated materials , titanium , and the organic medium include aliphatic hydrocarbons such as tantalum ; and carbon materials such as carbon cloths and hexane ; aromatic hydrocarbons such as benzene , toluene , carbon papers . Of these , metallic materials are preferred . xylene , and methylnaphthalene ; heterocyclic compounds Especially preferred is aluminum . such as quinoline and pyridine ; ketones such as acetone, 20 In the case of a metallic material, examples of the shape methyl ethyl ketone , and cyclohexanone ; esters such as of the current collector include metal foils , metal cylinders , methyl acetate and methyl acrylate ; amines such as dieth metal coils , metal plates , thin metal films, expanded metals , ylenetriamine and N , N - dimethylaminopropylamine ; ethers punching metals, and metal foams. In the case of a carbon such as diethyl ether and tetrahydrofuran ( THF ) ; amides material, examples of the collector shape include carbon such as N -methylpyrrolidone (NMP ) , dimethylformamide , 25 plates, thin carbon films, and carbon cylinders . Of these , a and dimethylacetamide ; and aprotic polar solvents such as thin metal film is preferred . The thin film may be in a hexamethylphosphoramide and dimethyl sulfoxide . One of suitable mesh form . these liquid media may be used alone, or any desired Although the current collector may have any desired combination of two or more thereof in any desired propor thickness , the thickness thereof is generally 1 um or larger, tion may be used . 30 preferably 3 um or larger, more preferably 5 um or larger , ( 5 ) Thickener and is generally 1 mm or smaller , preferably 100 um or When an aqueous medium is used as a liquid medium for smaller, more preferably 50 um or smaller. When the thin forming a slurry , it is preferred to use a thickener and a latex film is thinner than the lower limit of that range , there are of, e . g . , a styrene /butadiene rubber ( SBR ) to prepare a slurry. cases where this film is deficient in strength required of a A thickener is used generally for the purpose of regulating 35 current collector. When the thin film is thicker than the upper the viscosity of the slurry . limit of that range , there are cases where this film has The thickener is not particularly limited unless it consid - impaired handleability . erably lessens the effects of the invention . Examples thereof < 2 - 5 . Separator > include carboxymethyl cellulose , methyl cellulose , A separator is generally interposed between the positive hydroxymethyl cellulose , ethyl cellulose , poly ( vinyl alco - 40 electrode and the negative electrode in order to prevent hol) , oxidized starch , phosphorylated starch , casein , and short -circuiting . In this case, the nonaqueous electrolyte of salts of these . One of these thickeners may be used alone , or this invention are usually infiltrated into the separator. any desired combination of two or more thereof in any The material and shape of the separator are not particu desired proportion may be used . larly limited , and known separators can be employed at will In the case where such a thickener is further used , the 45 unless the effects of the invention are considerably lessened proportion of the thickener to the active material desirably is thereby . In particular , use may be made of separators con generally 0 . 1 % by mass or higher, preferably 0 . 5 % by mass stituted of materials stable to the nonaqueous electrolyte of or higher , more preferably 0 . 6 % by mass or higher , and is the invention , such as resins , glass fibers , and inorganic generally 5 % by mass or lower, preferably 3 % by mass or materials. It is preferred to use a separator which is in the lower, more preferably 2 % by mass or lower. When the 50 form of a porous sheet , nonwoven fabric , or the like and has proportion thereof is lower than the lower limit of that range , excellent liquid retentivity . there are cases where applicability decreases considerably . As the material of the resinous or glass- fiber separators, Proportions thereof exceeding the upper limit of that range use can be made of, for example , polyolefins such as result in a reduced proportion of the active material in the polyethylene and polypropylene , polytetrafluoroethylene , positive - electrode active -material layer , and this may pose a 55 polyethersulfones , glass filters , and the like . Preferred of problem that battery capacity decreases and a problem that these are glass filters and polyolefins . More preferred are resistance among the particles of the positive - electrode polyolefins. One of these materials may be used alone, or active material increases. any desired combination of two or more thereof in any (6 ) Compaction desired proportion may be used . It is preferred that the positive -electrode active -material 60 The separator may have any desired thickness . However , layer obtained by coating fluid application and drying should the thickness thereof is generally 1 um or larger, preferably be compacted with a handpress, roller press, or the like in 5 um or larger, more preferably 10 um or larger, and is order to heighten the loading density of the positive - elec generally 50 um or smaller, preferably 40 um or smaller, trode active material. The density of the positive - electrode more preferably 30 um or smaller . When the separator is active -material layer is preferably 1 gócm -> or higher ,more 65 thinner than the lower limit of that range , there are cases preferably 1 . 5 g . cm - 3 or higher, especially preferably 2 where insulating properties and mechanical strength g .cm3 or higher. The upper limit thereof is preferably 4 decrease . When the separator is thicker than the upper limit US 9 ,853 , 326 B2 70 of that range , there are cases where battery performances pressure . This battery is reduced in various characteristics including rate characteristics decrease . In addition , there including charge /discharge cycling performance and high also are cases where use of such a separator gives a temperature storability, and there are even cases where the nonaqueous- electrode secondary battery which as a whole gas release valve , which releases the gas from the internal has a reduced energy density . 5 pressure , works . In the case where a porous material such as, e . g ., a porous [Current Collector Structure ] sheet or a nonwoven fabric is used as the separator , this The current collector structure is not particularly limited . separator may have any desired porosity . However, the porosity thereof is generally 20 % or higher, preferably 35 % However , for more effectively realizing the improvement in or higher , more preferably 45 % or higher, and is generally 10 discharge characteristics which is brought about by the 90 % or lower , preferably 85 % or lower, more preferably nonaqueous electrolyte of this invention , it is preferred to 75 % or lower . In case where the porosity thereof is lower employ a structure reduced in the resistance of wiring parts than the lower limit of that range , this separator tends to have and joint parts . In the case where internal resistance has been increased film resistance , resulting in impaired rate charac reduced in this manner, use of the nonaqueous electrolyte of teristics. In case where the porosity thereof is higher than the 15 the invention produces its effects especially satisfactorily . upper limit of that range , this separator tends to have In the case of electrode groups assembled into the mul reduced mechanical strength and reduced insulating prop - tilayer structure described above , a structure obtained by erties. bundling the metallic core parts of respective electrode The separator may have any desired average pore diam layers and welding the bundled parts to a terminal is eter. However , the average pore diameter thereof is generally 20 suitable. When each electrode has a large area , this results in 0 . 5 um or smaller , preferably 0 . 2 um or smaller , and is increased internal resistance . In this case , it is preferred to generally 0 .05 um or larger. In case where the average pore dispose two or more terminals in each electrode to reduce diameter thereof exceeds the upper limit of that range, the resistance . In the case of an electrode group having the short -circuiting is apt to occur. When the average pore wound structure described above , two or more lead struc diameter thereof is smaller than the lower limit of that range , 25 tures may be disposed on each of the positive electrode and there are cases where this separator has increased film negative electrode and bundled into a terminal, whereby resistance , resulting in reduced rate characteristics . internal resistance can be reduced . On the other hand , examples of the inorganic materials [Case ] which may be used include oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon 30 asiThe material of the case is not particularly limited so long nitride , and sulfates such as barium sulfate and calcium as it is a substance stable to the nonaqueous electrolyte to be sulfate . Such materials of a particulate shape or fibrous used . For example , use may be made of metals such as shape may be used . nickel- plated steel sheets , stainless steel , aluminum or alu With respect to form , a separator of a thin film form may minum alloys , and magnesium alloys or laminated films be used , such as a nonwoven fabric , woven fabric , or 355 constituted of a resin and an aluminum foil. From the microporous film . Suitable ones of a thin film form have a standpoint of weight reduction , it is preferred to use a metal pore diameter of 0 .01 - 1 um and a thickness of 5 - 50 um . which is aluminum or an aluminum alloy or a laminated Besides such a separator in an independent thin film form , film . use can be made of a separator obtained by forming a Examples of the case made of such a metal include one of composite porous layer containing particles of the inorganic 40 a sealed structure formed by fusion -bonding metallic mem material with a resinous binder on a surface layer of the bers to each other by laser welding , resistance welding , or positive electrode and / or negative electrode . Examples of ultrasonic welding and one of a caulked structure obtained such separators include a porous layer formed by fixing by caulkingmembers of the metal through a resinous gasket . alumina particles having a 90 % particle diameter smaller Examples of the case made of the laminated film include one than 1 um with a fluororesin as a binder on both sides of the 45 of a sealed structure formed by thermally fusion -bonding positive electrode. resin layers to each other . For the purpose of enhancing < 2 - 6 . Battery Design > sealability , a resin different from the resin used in the [ Electrode Group ] laminated film may be interposed between the resin layers . The electrode group may be either of: one having a Especially when resin layers are to be thermally fusion multilayer structure in which the positive - electrode plate and 50 bonded to each other through a current collector terminal to negative - electrode plate described above have been super produce a sealed structure , metal /resin bonding is necessary posed through the separator described above ; and one hav - and , hence , a resin having polar groups or a modified resin ing a wound structure in which the positive - electrode plate having polar groups introduced therein is suitable for use as and negative - electrode plate described above have been the resin to be interposed . spirally wound through the separator described above . The 55 [Protective Element] proportion of the volume of the electrode group to the Examples of the protective element include a PTC (posi internal volume of the battery (hereinafter referred to as tive temperature coefficient) , which increases in resistance electrode group proportion ) is generally 40 % or higher, upon abnormal heating -up or when an excessive current preferably 50 % or higher, and is generally 90 % or lower , flows, a temperature fuse , a thermister , and a valve ( current preferably 80 % or lower. In case where the electrode group 60 breaker valve ) which breaks current flow through the circuit proportion is lower than the lower limit of that range , a in abnormal heating- up based on an abrupt increase in the decrease in battery capacity results . In case where the internal pressure or internal temperature of the battery. It is electrode group proportion exceeds the upper limit of that preferred to select such a protective element which does not range, this battery has a reduced space volume. There are work under ordinary high - current use conditions . From the hence cases where battery heating -up causes members to 65 standpoint of high output, it is preferred to employ a design expand and a liquid component of the electrolyte to have a which prevents abnormal heating -up and thermal run -away heightened vapor pressure , resulting in an increased internal even without a protective element. US 9 ,853 , 326 B2 [ Casing ] 1 . The phenomena which occur when the concentration is The nonaqueous- electrolyte secondary battery of this outside the range also are the same as those described above invention is usually fabricated by housing the nonaqueous with regard to nonaqueous electrolyte 1 . electrolyte , negative electrode, positive electrode, separator, Especially in the case where the nonaqueous solvent of etc . in a casing . This casing is not limited , and a known one 5 the nonaqueous electrolyte consists mainly of one or more can be employed at will unless this considerably lessens the carbonate compounds such as alkylene carbonates or dialkyl effects of the invention . The casing may be made of any desired material. For carbonates, preferred electrolytes and the proportion thereof example , however, nickel- plated iron , stainless steel , alumi are the same as those described above with regard to num or an alloy thereof, nickel , titanium , or the like is 10 nonaqueous electrolyte 1 . The phenomena which occur generally used when the proportion is outside the range also are the same The casing may have any desired shape . For example , the as those described above with regard to nonaqueous elec casing may be any of the cylindrical type , prismatic type , trolyte 1 . laminate type , coin type, large type , and the like . In the case where the nonaqueous solvent of this non When a carbonate having a halogen atom and a mono - 15is aquaqueous electrolyte includes at least 50 % by volume cyclic fluorophosphate and / or difluorophosphate are incorporated carboxylic acid ester compound such as, e. g. , y -butyrolac into a nonaqueous electrolyte and this nonaqueous electro - tone or y - valerolactone , it is preferred that LiBF4 should lyte is used to fabricate a nonaqueous - electrode secondary account for 50 mol % or more of all lithium salts . battery , then thishis secondary battery can have improved < 1 - 2 . Nonaqueous Solvent > storability in high - temperature environments . Details of the 20 Nonaqueous electrolyte 2 of the invention contains “ a reasons for this are unclear. However, it is presumed that the compound which is liquid at 25° C ., has a permittivity of 5 coexistence of a carbonate having a halogen atom with a or higher and a coefficient of viscosity of 0 . 6 cP or lower , monofluorophosphate and / or difluorophosphate in the elec - and has a group constituting a heteroelement - containing trolyte contributes to an improvement in the properties of a framework (excluding carbonyl group ) ” . protective coating film in some way . Furthermore , it is 25 < 1 - 2 - 1 . Compound which is Liquid at 25° C ., has Permit presumed that use of the carbonate having a halogen atom as tivity of 5 or Higher and Coefficient of Viscosity of 0 . 6 cP a solvent improves the oxidation resistance of the nonaque - or Lower, and has Group Constituting Heteroelement -Con ous electrolyte and hence inhibits this electrolyte from taining Framework ( Excluding Carbonyl Group ) > reacting with the positive -electrode active material . This The " compound which is liquid at 25° C . , has a permit nonaqueous electrolyte is presumed to contribute to an 30 tivity of 5 or higher and a coefficient of viscosity of 0 . 6 CP improvement in storability . or lower, and has a group constituting a heteroelement < Nonaqueous Electrolyte 2 and Nonaqueous -Electrolyte containing framework ( excluding carbonyl group ) ” in Secondary Battery 2 > invention 2 is not particularly limited so long as it is a [ 1 . Nonaqueous Electrolyte 2 for Secondary Battery ] compound within the scope of this definition . However, it is The nonaqueous electrolyte for use in nonaqueous - elec - 35 preferred that the compound should be a compound having trolyte secondary battery 2 of the invention (hereinafter an ether framework and / or a nitrile framework in view of the suitably referred to as “ nonaqueous electrolyte 2 in the properties of the nonaqueous electrolyte. Namely , a com invention ” ) is a nonaqueous electrolyte mainly comprising a pound having at least one ether group or nitrile group as part nonaqueous solvent and an electrolyte dissolved therein , and of the structure is preferred . is characterized by containing a compound which is liquid at 40 It is more preferred that the compound having an ether 25° C ., has a permittivity of 5 or higher and a coefficient of framework and /or a nitrile framework should further have an viscosity of 0 .6 cP or lower, and has a group constituting a alkyl group which may have one or more substituents , from heteroelement - containing framework ( excluding carbonyl the standpoint of reducing the electrochemical reactivity of framework ) and by further containing a monofluorophos the compound . The “ alkyl group ” represents an acyclic alkyl phate and / or a difluorophosphate . 45 group or a cyclic alkyl group . < 1 - 1 . Electrolyte > In the case where the compound is a compound having an The electrolyte to be used in nonaqueous electrolyte 2 of ether framework , the ether framework in cooperation with the invention is not limited , and known ones for use as an alkylene group may have formed a saturated cyclic electrolytes in a target nonaqueous - electrolyte secondary compound which may have one or more substituents . battery can be employed and incorporated at will. In the case 50 Namely , that compound may be a cyclic ether which may where nonaqueous electrolyte 2 of the invention is to be used have one or more substituents. in nonaqueous -electrolyte secondary batteries, the electro - Preferred substituents of the “ compound having an ether lyte preferably is one or more lithium salts . framework and /or a nitrile framework ” are halogen substitu Examples of the electrolyte include the same electrolytes ents and /or “ saturated aliphatic hydrocarbon substituents as those shown above with regard to nonaqueous electrolyte 55 having no substituents other than halogen atoms” , from the 1 . standpoint of the reactivity thereof . Preferred of these is LiPF6, LiBF4, LiCF2SO3, LiN Although such substituents of the compound preferably ( CF SO , ) , LiN ( C , F SO , ) , or lithium bis ( oxalato )borate . are halogen substituents , alkoxycarbonyl substituents , Especially preferred is LiPF , or LiBF4. alkoxycarboxyl substituents, and alkylcarboxyl substituents In the case of using a combination of electrolytes, the 60 from the standpoint of the reactivity thereof, there is a fear kinds of the electrolytes and the proportions of the electro - about an increase in viscosity coefficient . Because of this , lytes are the same as those described above with regard to fluorine atoms are preferred as the substituents . nonaqueous electrolyte 1 . Examples of the “ compound which is liquid at 25° C . , has Furthermore , the lithium salt concentration , preferred a permittivity of 5 or higher and a coefficient of viscosity of concentration , and the like in the final composition of 65 0 .6 cP or lower, and has a group constituting a heteroele nonaqueous electrolyte 2 of the invention are the same as ment -containing framework ( excluding carbonyl group ) ” in those described above with regard to nonaqueous electrolyte invention 2 include dimethoxyethane , diethoxyethane , US 9 ,853 , 326 B2 73 74 ethoxymethoxyethane , tetrahydrofuran , tetrahydropyran , constituting each cyclic carbonate is preferably 2 - 6 , espe 1 , 3 -dioxolane , acetonitrile , propionitrile , and fluoroacetoni cially preferably 2 -4 . Examples of the cyclic carbonate trile and the like . 11include ethylene carbonate , propylene carbonate , and buty The permittivity of the “ compound which is liquid at 25° lene carbonate ( 2 - ethylethylene carbonate or cis - and trans C ., has a permittivity of 5 or higher and a coefficient of 5 2 ,3 -dimethylethylene carbonates) and the like. viscosity of 0 .6 cP or lower , and has a group constituting a Of these , ethylene carbonate or propylene carbonate is heteroelement - containing framework ( excluding carbonyl preferred because these compounds are satisfactory in vari group ) ” in invention 2 is measured by the method described ous properties in a nonaqueous - electrolyte secondary bat in The Electrochemical Society of Japan ed ., Denki Kagaku tery . Sokutei Manyuaru Jissen -hen , page 13 . The value deter- 10 The acyclic carboxylic acid esters also are not limited in mined by this measurement is defined as permittivity in the kind thereof. Examples thereof include methyl acetate , invention 2 . ethyl acetate, n -propyl acetate, isopropyl acetate , n -butyl The coefficient of viscosity of the “ compound which is acetate , isobutyl acetate , tert- butyl acetate , methyl propi liquid at 25° C ., has a permittivity of 5 or higher and a onate , ethyl propionate , n - propyl propionate , isopropyl pro coefficient of viscosity of 0 . 6 cP or lower, and has a group 15 pionate , n -butyl propionate, isobutyl propionate , and tert constituting a heteroelement- containing framework ( exclud - butyl propionate and the like . ing carbonyl group ) ” is measured with an Ostwald viscom - Of these , ethyl acetate , methyl propionate , or ethyl pro eter. The value determined by this measurement is defined as pionate is preferred from the standpoint of industrial avail the coefficient of viscosity in invention 2 . Incidentally , " cP ” ability and the reason that these compounds are satisfactory means " centipoises ” . 20 in various properties in a nonaqueous -electrolyte secondary It is essential that the compound should have a permit - battery . tivity of 5 or higher. The permittivity thereof is preferably The cyclic carboxylic acid esters also are not limited in 5 . 1 or higher, more preferably 5 . 2 or higher , especially the kind thereof. Examples of such esters in ordinary use preferably 5 . 3 or higher . It is essential that the compound include y -butyrolactone , y - valerolactone , and d - valerolac should have a coefficient of viscosity of 0 . 6 cP or lower. The 25 tone . coefficient of viscosity thereof is preferably 0 . 5 cP or lower . Of these , y -butyrolactone is preferred from the standpoint When a compound having a permittivity of 5 or higher of industrial availability and the reason that this compound and a coefficient of viscosity of 0 .6 cP is used , ( there is an is satisfactory in various properties in a nonaqueous - elec advantage that it is possible to produce an electrolyte which trolyte secondary battery . has low resistance , attains high ion movability , and has high 30 The phosphorus - containing organic solvents also are not infiltrating properties . In general, such compounds having a particularly limited in the kind thereof. Examples thereof permittivity of 5 or higher and a coefficient of viscosity of include 0 .6 cP or lower are susceptible to electrochemical decom phosphoric acid esters such as trimethyl phosphate , triethyl position . However , the electrochemical decomposition can phosphate , and triphenyl phosphate ; be inhibited by using such compound in combination with a 35 phosphorous acid esters such as trimethyl phosphite, triethyl monofluorophosphate and /or a difluorophosphate . phosphite, and triphenyl phosphite ; and < 1 - 2 - 2 . Other Nonaqueous Solvents > phosphine oxides such as trimethylphosphine oxide , trieth Nonaqueous electrolyte 2 of the invention may contain a ylphosphine oxide , and triphenylphosphine oxide and the nonaqueous solvent other than the “ compound which is like . liquid at 25° C ., has a permittivity of 5 or higher and a 40 Furthermore , the sulfur- containing organic solvents also coefficient of viscosity of 0 .6 cP or lower , and has a group are not particularly limited in the kind thereof. Examples constituting a heteroelement - containing framework ( exclud - thereof include ing carbonyl group ) " , or may contain no nonaqueous solvent ethylene sulfite , 1 , 3 - propanesultone, 1 , 4 - butanesultone , other than that compound . Nonaqueous solvents which do methyl methanesulfonate , busulfan , sulfolane , sulfolene , not adversely influence battery characteristics after battery 45 dimethyl sulfone , diphenyl sulfone , methyl phenyl sulfone, fabrication may be incorporated without particular limita dibutyl disulfide , dicyclohexyl disulfide , tetramethylthiuram tions on the use and kind thereof. Such optional solvents monosulfide , N ,N -dimethylmethanesulfonamide , and N ,N preferably are one or more members selected from the diethylmethanesulfonamide and the like . nonaqueous solvents enumerated below . Of those compounds, the acyclic or cyclic carbonates or Examples of the usable nonaqueous solvents include 50 the acyclic or cyclic carboxylic acid esters are preferred acyclic or cyclic carbonates , acyclic or cyclic carboxylic because these compounds are satisfactory in various prop acid esters , phosphorus - containing organic solvents , and erties in a nonaqueous - electrolyte secondary battery . More sulfur- containing organic solvents and the like. preferred of these is ethylene carbonate , propylene carbon The acyclic carbonates also are not limited in the kind ate , dimethyl carbonate , ethyl methyl carbonate , diethyl thereof. However , dialkyl carbonates are preferred . The 55 carbonate, ethyl acetate , methyl propionate , ethyl propi number of carbon atoms of each constituent alkyl group is onate, or y -butyrolactone . Even more preferred is ethylene preferably 1 - 5 , especially preferably 1 - 4 . Examples thereof carbonate, propylene carbonate, dimethyl carbonate , ethyl include dimethyl carbonate , ethylmethyl carbonate , diethyl methyl carbonate , diethyl carbonate , ethyl acetate , methyl carbonate , methyl- n -propyl carbonate , ethyl n - propyl car- propionate , or y - butyrolactone . bonate , and di- n -propyl - carbonate and the like . 60 < 1 - 2 -3 . Others > Of these , dimethyl carbonate , ethyl methyl carbonate , or The “ compound which is liquid at 25° C . , has a permit diethyl carbonate is preferred from the standpoint of indus - tivity of 5 or higher and a coefficient of viscosity of 0 . 6 CP trial availability and the reason that these compounds are or lower, and has a group constituting a heteroelement satisfactory in various properties in a nonaqueous - electro - containing framework ( excluding carbonyl group ) ” may be lyte secondary battery . 65 used alone or in combination with one or more of the other The cyclic carbonates are not limited in the kind thereof. nonaqueous solvents shown above . However , it is preferred However, the number of carbon atomsof the alkylene group to employ a combination of two or more compounds includ US 9 ,853 , 326 B2 75 76 ing the “ compound which is liquid at 25° C . , has a permit charge load characteristics while maintaining the properties tivity of 5 or higher and a coefficient of viscosity of 0 . 6 cp of the combination of ethylene carbonate and one or more or lower , and has a group constituting a heteroelement - acyclic carbonates . containing framework ( excluding carbonyl group ) ” . For More preferred of these are combinations including an example , it is preferred to use a high - permittivity solvent, 5 asymmetric acyclic carbonate . In particular, combinations such as a cyclic carbonate , in combination with a low - including ethylene carbonate , a symmetric acyclic carbon viscosity solvent, such as an acyclic carbonate or an acyclic ate , and an asymmetric acyclic carbonate , such as a combi ester. nation of ethylene carbonate , dimethyl carbonate , and ethyl For example , it is preferred to use : a combination of a methyl carbonate , a combination of ethylene carbonate , high -permittivity solvent, e . g ., a cyclic carbonate, and the 10 diethyl carbonate, and ethyl methyl carbonate, and a com " compound which is liquid at 25° C . , has a permittivity of b ination of ethylene carbonate , dimethyl carbonate , diethyl 5 or higher and a coefficient of viscosity of 0 . 6 cP or lower, carbonate , and ethyl methyl carbonate , or such combinations and has a group constituting a heteroelement- containing which further contain propylene carbonate are preferred framework (excluding carbonyl group ) " ; or a combination because these combinations have a satisfactory balance of a high - permittivity solvent, e . g ., a cyclic carbonate , a 15 between cycle characteristics and discharge load character low - viscosity solvent, e . g . , an acyclic carbonate or an acy - istics. Preferred of such combinations are ones in which the clic ester , and the “ compound which is liquid at 25° C ., has asymmetric acyclic carbonate is ethyl methyl carbonate . a permittivity of 5 or higher and a coefficient of viscosity of Furthermore , the number of carbon atoms of each of the 0 .6 cP or lower, and has a group constituting a heteroele alkyl groups constituting each dialkyl carbonate is prefer ment- containing framework (excluding carbonyl group )” . It 20 ably 1 -2 . is especially preferred to use the " compound which is liquid Other examples of preferred mixed solvents are ones at 25° C . , has a permittivity of 5 or higher and a coefficient containing an acyclic ester. In particular, the cyclic carbon of viscosity of 0 . 6 cP or lower, and has a group constituting ate / acyclic carbonate mixed solvents which contain an acy a heteroelement -containing framework (excluding carbonyl clic ester are preferred from the standpoint of improving the group ) ” in combination with one or more members selected 25 discharge load characteristics of a battery . The acyclic ester from nonaqueous solvents including cyclic carbonates and especially preferably is ethyl acetate or methyl propionate . acyclic carbonates . The proportion by volume of the acyclic ester to the non In particular, the total proportion of the cyclic carbonate aqueous solvent is generally 5 % or higher, preferably 8 % or and the acyclic carbonate to the whole nonaqueous solvent higher , more preferably 15 % or higher, and is generally 50 % is generally 80 % by volume or higher , preferably 85 % by 30 or lower, preferably 35 % or lower , more preferably 30 % or volume or higher , more preferably 90 % by volume or higher . lower, even more preferably 25 % or lower . The proportion by volume of the cyclic carbonate to the sum Other preferred examples of nonaqueous solvents are of the cyclic carbonate and the acyclic carbonate is prefer - ones in which one organic solvent selected from the group ably 5 % by volume or higher, more preferably 10 % by consisting of ethylene carbonate , propylene carbonate, buty volume or higher, especially preferably 15 % by volume or 35 lene carbonate , y -butyrolactone , and y -valerolactone or a higher , and is generally 50 % by volume or lower , preferably mixed solvent composed of two or more organic solvents 35 % by volume or lower , more preferably 30 % by volume selected from the group accounts for at least 60 % by volume or lower. Use of such combination of nonaqueous solvents of the whole . Such mixed solvents have a flash point of is preferred because the battery fabricated with this combi preferably 50° C . or higher , especially preferably 70° C . or nation has an improved balance between cycle characteris - 40 higher. The nonaqueous electrolyte employing this solvent is tics and high - temperature storability ( in particular , residual reduced in solvent vaporization and liquid leakage even capacity and high - load discharge capacity after high -tem - when used at high temperatures. In particular, when such a perature storage ). nonaqueous solvent which includes ethylene carbonate and Examples of the preferred combination including at least y - butyrolactone in a total amount of 80 % by volume or one cyclic carbonate and at least acyclic carbonate include : 45 larger, preferably 90 % by volume or larger, based on the ethylene carbonate and dimethyl carbonate ; ethylene car - nonaqueous solvent and in which the volume ratio of the bonate and diethyl carbonate ; ethylene carbonate and ethyl ethylene carbonate to the y - butyrolactone is from 5 : 95 to methyl carbonate ; ethylene carbonate , dimethyl carbonate , 45 : 55 or such a nonaqueous solvent which includes ethylene and diethyl carbonate ; ethylene carbonate, dimethyl carbon - carbonate and propylene carbonate in a total amount of 80 % ate , and ethylmethyl carbonate ; ethylene carbonate , diethyl 50 by volume or larger, preferably 90 % by volume or larger, carbonate , and ethyl methyl carbonate ; and ethylene carbon based on the whole nonaqueous solvent and in which the ate , dimethyl carbonate , diethyl carbonate , and ethylmethyl volume ratio of the ethylene carbonate to the propylene carbonate and the like . carbonate is from 30 :70 to 80 : 20 is used , then an improved Combinations obtained by further adding propylene car - balance between cycle characteristics and discharge load bonate to those combinations including ethylene carbonate 55 characteristics , etc . is generally obtained . and one or more acyclic carbonates are also included in < 1 - 3 . Monofluorophosphate and Difluorophosphate > preferred combinations. In the case where propylene car- Nonaqueous electrolyte 2 of the invention contains a bonate is contained , the volume ratio of the ethylene car - monofluorophosphate and/ or a difluorophosphate as an bonate to the propylene carbonate is preferably from 99 : 1 to essential component. With respect to the “ monofluorophos 40 :60 , especially preferably from 95 : 5 to 50 : 50 . It is also 60 phate and difluorophosphate ” to be used in invention 2 , the preferred to regulate the proportion of the propylene car - kinds and contents thereof, places where the salts exist, bonate to the whole nonaqueous solventto a value which is methods of analysis , production process , etc . are the same as 0 .1 % by volume or higher , preferably 1 % by volume or those described above with regard to nonaqueous electrolyte higher , more preferably 2 % by volume or higher , and is 1 . generally 10 % by volume or lower , preferably 8 % by 65 < 1- 4 . Additives > volume or lower, more preferably 5 % by volume or lower . Nonaqueous electrolyte 2 of the invention may contain This is because this regulation brings about excellent dis - various additives so long as these additives do not consid US 9 , 853, 326 B2 77 78 erably lessen the effects of invention 2 . In the case where < 1 - 4 - 1 - 2 . Halogenated Carbonate > additives are additionally incorporated to prepare the non - On the other hand , the carbonate having a halogen atom aqueous electrolyte , conventionally known additives can be (hereinafter often referred to as “ halogenated carbonate ” ) as used at will. One additive may be used alone , or any desired one form of the specific carbonate according to invention 2 ro 5 is not particularly limited so long as it is a carbonate having combination of two or more additives in any desired pro - 5 a halogen atom , and any desired halogenated carbonate can portion may be used . be used . The same carbonates as those shown above under Examples of the additives include overcharge inhibitors “ Carbonate Having Halogen Atom ” with regard to nonaque and aids for improving capacity retentivity after high -tem ous electrolyte 1 can be used . Of these examples , preferred perature storage and cycle characteristics. It is preferred to embodiments of the " halogenated carbonate ” in nonaqueous add a carbonate having at least either of an unsaturated bond " electrolyte 2 are shown below . and a halogen atom (hereinafter sometimes referred to as Examples of the halogen atoms include fluorine , chlorine , “ specific carbonate ” ) as an aid for improving capacity bromine, and iodine atoms. Preferred of these are fluorine retentivity after high -temperature storage and cycle charac atoms or chlorine atoms . Especially preferred are fluorine atoms. The number of halogen atoms possessed by the teristics , among those additives. The specific carbonate and 1518 halogenated carbonate also is not particularly limited so long other additives are separately explained below . as the number thereof is 1 or larger . However, the number < 1 - 4 - 1. Specific Carbonate > thereof is generally 6 or smaller , preferably 4 or smaller . In The specific carbonate is a carbonate having at least either the case where the halogenated carbonate has two or more of an unsaturated bond and a halogen atom . The specific halogen atoms, these atoms may be the same or different. carbonate may have an unsaturated bond only or have a 20 Examples of the halogenated carbonate include ethylene halogen atom only , or may have both an unsaturated bond carbonate derivatives, dimethyl carbonate derivatives, ethyl and a halogen atom . methyl carbonate derivatives, and diethyl carbonate deriva The molecular weight of the specific carbonate is not tives . particularly limited , and may be any desired value unless Examples of the ethylene carbonate derivatives include this considerably lessens the effects of invention 2 . How - 25 fluoroethylene carbonate , chloroethylene carbonate , 4 , 4 - di ever, the molecular weight thereof is generally 50 or higher, fluoroethylene carbonate , 4 , 5 -difluoroethylene carbonate , preferably 80 or higher, and is generally 250 or lower , 4 , 4 - dichloroethylene carbonate , 4 , 5 -dichloroethylene car preferably 150 or lower . When the molecular weight thereof bonate , 4 - fluoro - 4 -methylethylene carbonate , 4 -chloro -4 is too high , this specific carbonate has reduced solubility in methylethylene carbonate , 4 , 5 - difluoro - 4 -methylethylene the nonaqueous electrolyte and there are cases where the 30 carbonate, 4 , 5 -dichloro - 4 -methylethylene carbonate , effect of the carbonate is difficult to produce sufficiently . 4 - fluoro - 5 -methylethylene carbonate , 4 - chloro - 5 -methyleth Processes for producing the specific carbonate also are not ylene carbonate , 4 , 4 -difluoro - 5 -methylethylene carbonate , particularly limited , and a known process selected at will can 4 , 4 -dichloro - 5 -methylethylene carbonate , 4 - ( fluoromethyl) be used to produce the carbonate . ethylene carbonate , 4 - chloromethyl) -ethylene carbonate , Any one specific carbonate may be incorporated alone 35 4 - ( difluoromethyl) - ethylene carbonate , 4 - ( dichloromethyl) into nonaqueous electrolyte 2 of the invention , or any ethylene carbonate , 4 - ( trifluoromethyl) -ethylene carbonate , desired combination of two or more specific carbonates may 4 - ( trichloromethyl) - ethylene carbonate , 4 -( fluoromethyl) -4 be incorporated thereinto in any desired proportion . fluoroethylene carbonate , 4 - chloromethyl) - 4 - chloroethyl The amount of the specific carbonate to be incorporated ene carbonate , 4 - ( fluoromethyl) - 5 - fluoroethylene carbonate , into nonaqueous electrolyte 2 of the invention is not limited , 40 4 - ( chloromethyl) - 5 - chloroethylene carbonate , 4 - fluoro - 4 , 5 and may be any desired value unless this considerably dimethylethylene carbonate , 4 -chloro - 4 , 5 - dimethylethylene lessens the effects of invention 2 . It is, however, desirable carbonate, 4 , 5 - difluoro - 4 , 5 - dimethylethylene carbonate , that the specific carbonate should be incorporated in a 4 , 5 -dichloro -4 , 5 - dimethylethylene carbonate , 4 ,4 -difluoro concentration which is generally 0 .01 % by mass or higher , 5 , 5 -dimethylethylene carbonate , and 4 , 4 - dichloro - 5 , 5 -dim preferably 0 . 1 % by mass or higher , more preferably 0 . 3 % by 45 ethylethylene carbonate and the like. mass or higher , and is generally 70 % by mass or lower , Examples of the dimethyl carbonate derivatives include preferably 50 % by mass or lower , more preferably 40 % by fluoromethylmethyl carbonate , difluoromethyl methyl car mass or lower, based on nonaqueous electrolyte 2 of the bonate , trifluoromethyl methyl carbonate , bis ( fluoromethyl) invention . carbonate, bis ( difluoromethyl carbonate, bis ( trifluorom When the amount of the specific carbonate is below the 50 ethyl carbonate, chloromethyl methyl carbonate , dichlorom lower limit of that range , there are cases where use of this ethyl methyl carbonate , trichloromethyl methyl carbonate , nonaqueous electrolyte 2 of the invention in a nonaqueous - bis (chloromethyl ) carbonate , bis ( dichloro )methyl carbonate , electrolyte secondary battery results in difficulties in pro - and bis ( trichloro )methyl carbonate and the like. ducing the effect of sufficiently improving the cycle char Examples of the ethyl methyl carbonate derivatives acteristics of the nonaqueous - electrolyte secondary battery . 55 include On the other hand , when the proportion of the specific 2 - fluoroethyl methyl carbonate , ethyl fluoromethyl carbon carbonate is too high , there is a tendency that use of this ate , 2 , 2 -difluoroethyl methyl carbonate , 2 - fluoroethyl fluo nonaqueous electrolyte 2 of the invention in a nonaqueous romethyl carbonate , ethyl difluoromethyl carbonate , 2 , 2 , 2 electrolyte secondary battery results in decreases in the trifluoroethyl methyl carbonate , 2 , 2 - difluoroethyl high - temperature storability and continuous - charge charac - 60 fluoromethyl carbonate , 2 - fluoroethyl difluoromethyl car teristics of the nonaqueous- electrolyte secondary battery . In bonate , ethyl trifluoromethyl carbonate , 2 - chloroethyl particular, there are cases where gas evolution is enhanced methyl carbonate , ethyl chloromethyl carbonate, 2 , 2 - dichlo and capacity retentivity decreases . roethyl methyl carbonate , 2 -chloroethyl chloromethyl car < 1 - 4 - 1 - 1 . Unsaturated Carbonate > bonate , ethyl dichloromethyl carbonate , 2 , 2 , 2 -trichloroethyl The carbonate having an unsaturated bond (hereinafter 65 methyl carbonate , 2 , 2 -dichloroethyl chloromethyl carbon often referred to as “ unsaturated carbonate ” ) is the same as ate , 2 -chloroethyl dichloromethyl carbonate , and ethyl in nonaqueous electrolyte 1 . trichloromethyl carbonate and the like . US 9 ,853 , 326 B2 79 80 Examples of the diethyl carbonate derivatives include Examples of vinyl carbonates include Ethyl- ( 2 - fluoroethyl) carbonate , ethyl - ( 2 , 2 - difluoroethyl) fluoromethyl vinyl carbonate , 2 - fluoroethyl vinyl carbonate , carbonate , bis ( 2 - fluoroethyl ) carbonate , ethyl- ( 2 ,2 ,2 -trifluo 2 , 2 -difluoroethyl vinyl carbonate , 2 , 2 , 2 - trifluoroethyl vinyl roethyl) carbonate , 2 , 2 - difluoroethyl- 2 - fluoroethyl carbon - carbonate, chloromethyl vinyl carbonate , 2 - chloroethyl ate , bis ( 2 , 2 - difluoroethyl) carbonate , 2 , 2 , 2 - trifluoroethyl- 2 ' - 5 vinyl carbonate , 2 , 2 - dichloroethyl vinyl carbonate , and 2 , 2 , fluoroethyl carbonate , 2 , 2 , 2 - trifluoroethyl- 2 ', 2 '- difluoroethyl 2 - trichloroethyl vinyl carbonate and the like. carbonate , bis ( 2, 2 ,2 -trifluoroethyl ) carbonate , ethyl- ( 2 -chlo - Examples of the allyl carbonates include roethyl) carbonate , ethyl- ( 2 ,2 -dichloroethyl ) carbonate , bis fluoromethyl allyl carbonate , 2 - fluoroethyl allyl carbonate , ( 2 - chloroethyl ) carbonate , ethyl - ( 2 , 2 , 2 - trichloroethyl ) car- 2 , 2 - difluoroethyl allyl carbonate , 2 , 2 , 2 - trifluoroethyl allyl bonate , 2 , 2 - dichloroethyl- 2 - chloroethyl carbonate , bis( 2 , 2 - 10 carbonate , chloromethyl allyl carbonate , 2 - chloroethyl allyl dichloroethyl) carbonate , 2 , 2 , 2 - trichloroethyl- 2 -chloroethyl carbonate , 2 , 2 - dichloroethyl allyl carbonate , and 2 , 2 , 2 carbonate , 2 , 2 , 2 - trichloroethyl- 2 , 2 - dichloroethyl carbon - trichloroethyl allyl carbonate and the like . ate , and bis (2 , 2 , 2 -trichloroethyl ) carbonate and the like . It is especially preferred to use, as the specific carbonate , Preferred of these halogenated carbonates are the carbon - one or more members selected from the group consisting of ates having a fluorine atom . More preferred are the ethylene 15 vinylene carbonate , vinylethylene carbonate , fluoroethylene carbonate derivatives having a fluorine atom . In particular , carbonate , 4 , 5 - difluoroethylene carbonate , and derivatives fluoroethylene carbonate , 4 - ( fluoromethyl) -ethylene carbon - of these , among the examples of the halogenated unsaturated ate , 4 ,4 - difluoroethylene carbonate , and 4 , 5 -difluoroethyl carbocarbonate enumerated above. These carbonates are highly ene carbonate are more suitable because these carbonates effective even when used alone . form an interface - protective coating film . 20 < 1 - 4 - 2 . Other Additives > < 1 - 4 - 1 - 3 . Halogenated Unsaturated Carbonate > Examples of additives other than the specific carbonate Furthermore usable as the specific carbonate is a carbon - include overcharge inhibitors and aids for improving capac ate having both an unsaturated bond and a halogen atom ity retentivity after high -temperature storage and cycle char ( this carbonate is suitably referred to as “ halogenated acteristics . The " overcharge inhibitors ” and the " aids for unsaturated carbonate ” ) . This halogenated unsaturated car- 25 improving capacity retentivity after high - temperature stor bonate is not particularly limited , and any desired haloge - age and cycle characteristics ” are the same as those nated unsaturated carbonate can be used unless the effects of described above with regard to nonaqueous electrolyte 1. invention 2 are considerably lessened thereby . [2 . Nonaqueous- Electrolyte Secondary Battery ] Examples of the halogenated unsaturated carbonate Nonaqueous - electrolyte secondary battery 2 of the inven include vinylene carbonate derivatives , ethylene carbonate 30 tion includes: a negative electrode and a positive electrode derivatives substituted with one or more aromatic rings or which are capable of occluding and releasing ions ; and the with one or more substituents having a carbon -carbon nonaqueous electrolyte of this invention . unsaturated bond , and allyl carbonates. < 2 - 1 . Battery Constitution > Examples of the vinylene carbonate derivatives include Nonaqueous - electrolyte secondary battery 2 of the inven fluorovinylene carbonate , 4 - fluoro -5 -methylvinylene car - 35 tion may have the samebattery constitution as that described bonate , 4 - fluoro - 5 -phenylvinylene carbonate , 4 - ( trifluorom above with regard to nonaqueous- electrolyte secondary bat ethyl) vinylene carbonate , chlorovinylene carbonate , tery 1. 4 -chloro -5 -methylvinylene carbonate , 4 -chloro - 5 -phenylvi < 2 - 2 . Nonaqueous Electrolyte > nylene carbonate , and 4 - ( trichloromethyl) vinylene carbon - As the nonaqueous electrolyte , the nonaqueous electrolyte ate and the like . 40 2 of the invention described above is used . Incidentally , a Examples of the ethylene carbonate derivatives substi - mixture of nonaqueous electrolyte 2 of the invention and tuted with one or more aromatic rings or with one or more another nonaqueous electrolyte may be used so long as this substituents having a carbon - carbon unsaturated bond is not counter to the spirit of invention 2 . include < 2 - 3 . Negative Electrode > 4 - fluoro - 4 -vinylethylene carbonate , 4 - fluoro - 5 -vinylethyl - 45 The negative electrode of nonaqueous - electrolyte second ene carbonate , 4 ,4 - difluoro - 5 - vinylethylene carbonate , 4 ,5 - ary battery 2 may be the same as the negative electrode difluoro - 4 - vinylethylene carbonate , 4 - chloro - 5 - vinylethyl described above with regard to nonaqueous- electrolyte sec ene carbonate , 4 , 4 -dichloro - 5 -vinylethylene carbonate, 4 , 5 ondary battery 1 . dichloro - 4 - vinylethylene carbonate , 4 - fluoro - 4 , 5 - < 2 - 4 . Positive Electrode > divinylethylene carbonate , 4 ,5 -difluoro -4 ,5 - divinylethylene 50 The positive electrode of nonaqueous- electrolyte second carbonate , 4 - chloro - 4 , 5 - divinylethylene carbonate , 4 , 5 - di- ary battery 2 may be the same as the positive electrode chloro - 4 , 5 - divinylethylene carbonate , 4 - fluoro -4 - phenyleth - described above with regard to nonaqueous- electrolyte sec ylene carbonate , 4 - fluoro -5 -phenylethylene carbonate , 4 , 4 - ondary battery 1 . difluoro - 5 - phenylethylene carbonate , 4 , 5 - difluoro - 4 - < 2 - 5 . Separator > phenylethylene carbonate , 4 - chloro - 4 -phenylethylene 55 The separator of nonaqueous - electrolyte secondary bat carbonate , 4 - chloro - 5 -phenylethylene carbonate , 4 , 4 -di tery 2 may be the sameas the separator described above with chloro - 5 - phenylethylene carbonate , 4 , 5 - dichloro - 4 - phenyl- regard to nonaqueous- electrolyte secondary battery 1 . ethylene carbonate , 4 , 5 - difluoro - 4 , 5 - diphenylethylene car < 2 - 6 . Battery Design > bonate , and 4 ,5 -dichloro - 4 ,5 -diphenylethylene carbonate The battery design of nonaqueous - electrolyte secondary and the like . 60 battery 2 may be the same as the battery design described Examples of phenyl carbonates include above with regard to nonaqueous - electrolyte secondary bat fluoromethyl phenyl carbonate , 2 - fluoroethyl phenyl car- tery 1. bonate , 2, 2 -difluoroethyl phenyl carbonate , 2 , 2 ,2 - trifluoro 2 - chloroethyl phenyl carbonate , 2 , 2 -dichloroethyl phenyl 65 [ 1 . Nonaqueous Electrolyte ] carbonate , and 2 , 2 , 2 - trichloroethyl phenyl carbonate and the Nonaqueous electrolyte 3 of the invention is a nonaque like . ous electrolyte mainly comprising a nonaqueous solvent and US 9 ,853 , 326 B2 82 an electrolyte dissolved therein , the nonaqueous electrolyte Examples of the alkyl group substituted with a fluorine containing a monofluorophosphate and / or a difluorophos atom include trifluoromethyl, trifluoroethyl, and pentafluo phate and further containing “ at least one compound roethyl and the like. selected from the group consisting of compounds repre - Examples of the alkoxy group substituted with a fluorine sented by general formula ( 1 ) given above , nitrile com - 5 atom include trifluoromethoxy, trifluoroethoxy, and penta pounds , isocyanate compounds, phosphazene compounds, fluoroethoxy . disulfonic acid ester compounds, sulfide compounds , disul- Examples of the compound in which all of R ' , R2, and R3 fide compounds, acid anhydrides , lactone compounds hav are alkoxy groups include ing a substituent in the a - position , and compounds having a trimethyl phosphate , ethyl dimethyl phosphate , dimethyl carbon -carbon triple bond ” . Hereinafter , the at least one 10 n -propyl phosphate , n -butyl dimethyl phosphate , diethyl compound given in the quotation marks is referred to as methyl phosphate , ethyl n -propyl methyl phosphate , n -butyl " compound A of invention 3 ” . ethyl methyl phosphate , di- n -propyl methyl phosphate , < 1 - 1 . Electrolyte > n -butyl n -propyl methyl phosphate, di- n -butyl methyl phos Nonaqueous electrolyte 3 of the invention includes an 15 phate , triethyl phosphate , diethyl n - propyl phosphate , n -bu electrolyte and a nonaqueous solvent containing the elec - tyl diethyl phosphate , di- n - propyl ethyl phosphate , n - butyl trolyte dissolved therein . The electrolyte to be used in n -propyl ethyl phosphate , di -n -butyl ethyl phosphate , tri- n nonaqueous electrolyte 3 of the invention is not limited , and propyl phosphate, n -butyl di- n -propyl phosphate , di- n -butyl known ones for use as electrolytes in a target nonaqueous n - propyl phosphate , tri- n -butyl phosphate , cyclopentyl dim electrolyte secondary battery can be employed and incorpo - 20 ethyl phosphate , cyclopentyl diethyl phosphate , cyclopentyl rated at will. In the case where nonaqueous electrolyte 3 of di- n - propyl phosphate , cyclopentyl di - n -butyl phosphate , the invention is to be used in nonaqueous- electrolyte sec cyclopentyl ethyl methyl phosphate , dicyclopentyl methyl ondary batteries , one or more lithium salts are preferable of phosphate , tricyclopentyl phosphate , cyclohexyl dimethyl the electrolyte . phosphate , cyclohexyl diethyl phosphate, cyclohexyl di- n The electrolyte for use in nonaqueous electrolyte 3 of the 25 propyl phosphate , cyclohexyl di -n -butyl phosphate , cyclo invention is the same as that described above with regard to hexyl ethyl methyl phosphate , dicyclohexyl methyl phos nonaqueous electrolyte 1 of the invention . phate , tricyclohexyl phosphate , dimethyl trifluoromethyl < 1 - 2 . Compound A of Invention 3 > phosphate , diethyl trifluoromethyl phosphate , ethyl methyl Nonaqueous electrolyte 3 of the invention contains the trifluoromethyl phosphate, (2 , 2 ,2 - trifluoroethyl) dimethyl “ compound A of invention 3 ” . “ Compound A of invention 3 " 30 phosphate , diethyl ( 2 , 2 , 2 - trifluoroethyl )phosphate , ethyl may be a compound represented by general formula ( 1 ) , ( 2 , 2 , 2 - trifluoroethyl) methyl phosphate , (pentafluoroethyl ) nitrile compound , isocyanate compound , phosphazene com dimethyl phosphate , diethyl (pentafluoroethyl ) phosphate , pound , disulfonic acid ester compound , sulfide compounds, ethyl (pentafluoroethyl )methyl phosphate , bis (trifluorom disulfide compound , acid anhydride, lactone compound hav ethyl) methyl phosphate , tris ( trifluoromethyl) phosphate , bis ing a substituent in the a -position , or compound having a 35 ( 2 , 2 , 2 - trifluoroethyl) methyl phosphate , bis( 2 , 2 , 2 - trifluoro carbon -carbon triple bond . The compounds constituting the ethyl) trifluoromethyl phosphate , bis ( pentafluoroethyl) group of compounds for “ compound A of invention 3 ” in methyl phosphate , bis (pentafluoroethyl )trifluoromethyl phosphate , bis ( trifluoromethyl) ethyl phosphate, bis ( trifluo invention 3 are explained below in more detail . romethyl ) 2 , 2 , 2 -trifluoroethyl phosphate , bis ( trifluorom < 1 - 2 - 1. Compounds Represented by General Formula (1 ), 40 ethyl) pentafluoroethyl phosphate , bis ( 2 ,2 ,2 - trifluoroethyl) ethyl phosphate , tris ( 2 , 2 , 2 - trifluoroethyl ) phosphate , bis ( 2 , 2 , 2 , -trifloroethyl ) pentafluoroethyl phosphate , bis [Chemical Formula - 4 ] (pentafluoroethyl ) ethyl phosphate , bis (pentafluoroethyl ) - 2 , (1 ) 2 , 2 - trifluoroethyl phosphate , and tris (pentafluoroethyl ) 45 phosphate and the like . R ? — P - R3 Preferred of the phosphoric acid esters enumerated above are trimethyl phosphate , ethyl dimethyl phosphate , diethyl methyl phosphate , triethyl phosphate , dimethyl trifluorom [ In general formula (1 ) , R ', R , and R3 each independently 50 ethyl phosphate , diethyl trifluoromethyl phosphate , ethyl represent a fluorine atom , an alkyl group which has 1 - 12 methyl trifluoromethyl phosphate , ( 2 , 2 , 2 -trifluoroethyl ) dim carbon atoms and may be substituted with a fluorine atom , ethyl phosphate , diethyl ( 2 , 2 , 2 - trifluoroethyl )phosphate , or an alkoxy group which has 1 - 12 carbon atoms and may ethyl ( 2 , 2 , 2 - trifluoroethyl) methyl phosphate , (pentafluoro be substituted with a fluorine atom . ] ethyl) dimethyl phosphate , diethyl (pentafluoroethyl ) phos The alkyl group having 1 - 12 carbon atoms is not particu - 55 phate , ethyl ( pentafluoroethyl) methyl phosphate , larly limited . Examples thereof include acyclic or cyclic bis ( trifluoromethyl) methyl phosphate , tris ( trifluoromethyl) alkyl groups having preferably 1- 8 , more preferably 1 - 6 phosphate , bis ( 2, 2 ,2 -trifluoroethyl ) methyl phosphate , bis ( 2 , carbon atoms. Preferred of these are the acyclic alkyl 2 , 2 - trifluoroethyl ) trifluoromethyl phosphate , bis (pentafluo groups . Specific examples thereof include methyl, ethyl, roethyl) methyl p hosphate , bis (pentafluoroethyl ) n - propyl, isopropyl , n - butyl, isobutyl, sec -butyl , tert - butyl, 60 trifluoromethyl phosphate , bis ( trifluoromethyl ) ethyl pentyl, cyclopentyl, and cyclohexyl and the like. phosphate , bis ( trifluoromethyl) - 2 , 2 , 2 - trifluoroethyl phos The alkoxy group having 1 - 12 carbon atoms is not phate , bis (trifluoromethyl ) pentafluoroethyl phosphate , bis particularly limited . However , this group preferably is an ( 2 , 2 , 2 - trifluoroethyl ) ethyl phosphate , tris ( 2 , 2 , 2 - trifluoro alkoxy group having 1 - 8 carbon atoms, especially preferably ethyl) phosphate , bis ( 2 , 2 , 2 ,- trifloroethyl ) pentafluoroethyl 1 -6 carbon atoms. Examples thereof include methoxy, 65 phosphate , bis (pentafluoroethyl ) ethyl phosphate , bis ( penta ethoxy, n - propoxy, isopropoxy, n - butoxy, isobutoxy , sec fluoroethyl) - 2 , 2 , 2 - trifluoroethyl phosphate , tris (pentafluoro butoxy , and tert -butoxy and the like . ethyl ) phosphate , and the like. US 9 ,853 , 326 B2 83 84 Examples of the compound in which any one of R ' , R ?, ethyl ) ethylphosphonate , ( 2 - fluorocyclohexyl) ( 2 , 2 , 2 - trifluo and R3 is an alkyl group and any two of these are alkoxy roethyl) ethylphosphonate , ethyl ( 2 , 2 , 2 -trifluoroethyl ) groups include n - propylphosphonate , ethyl perfluoroethyl n - propylphos dimethylmethylphosphonate , diethyl ethylphosphonate , di phonate , cyclohexyl ( 2 , 2 , 2 - trifluoroethyl) n -propylphospho n - propyl n - propylphosphonate , diisopropyl isopropylphos - 5 nate , cyclohexyl perfluoroethyl n - propylphosphonate , per phonate , di- n -butyl n - butylphosphonate , diisobutyl isobutyl- fluoroethyl ( 2 , 2 , 2 - trifluoroethyl) n - propylphosphonate , phosphonate , di- tert -butyl t ert -butylphosphonate , (2 - fluorocyclohexyl) ( 2, 2 ,2 - trifluoroethyl) n -propylphospho dicyclopentyl cyclopentylphosphonate , dicyclohexyl cyclo - nate , ethyl ( 2 , 2 , 2 - trifluoroethyl) n -butylphosphonate , ethyl hexylphosphonate , diethyl methylphosphonate , di- n -propyl perfluoroethyl n -butylphosphonate , cyclohexyl ( 2, 2 ,2 -trif methylphosphonate , di- n - butyl methylphosphonate , dicy - 10 luoroethyl) n -butylphosphonate , cyclohexyl perfluoroethyl clopentyl methylphosphonate, dicyclohexyl methylphos - n -butylphosphonate , perfluoroethyl ( 2 ,2 , 2 - trifluoroethyl) phonate , dimethyl ethylphosphonate , di- n -propyl ethylphos n -butylphosphonate , (2 - fluorocyclohexyl) ( 2 ,2 , 2 - trifluoro phonate , di- n -butyl ethylphosphonate, dicyclopentyl ethyl) n -butylphosphonate , ethylphosphonate , dicyclohexyl ethylphosphonate, dimethyl ethyl (2 ,2 , 2 -trifluoroethyl ) cyclohexylphosphonate , ethyl n -propylphosphonate , diethyl n -propylphosphonate , dim - 15 perfluoroethyl cyclohexylphosphonate, cyclohexyl (2 , 2, 2 ethyl n -butylphosphonate , diethyl n -butylphosphonate , dim - trifluoroethyl) cyclohexylphosphonate, cyclohexyl perfluo ethyl cyclohexylphosphonate , diethyl cyclohexylphospho roethyl cyclohexylphosphonate , perfluoroethyl ( 2 , 2 , 2 - trif nate , ethyl methyl methylphosphonate , methyl n - propyl luoroethyl ) cyclohexylphosphonate , ( 2 - fluorocyclohexyl) ( 2 , methylphosphonate , n - butyl methyl methylphosphonate , 2 , 2 -trifluoroethyl ) cyclohexylphosphonate , cyclopentyl methyl methylphosphonate , cyclohexyl methyl 20 diperfluoromethyl perfluoromethylphosphonate , di( 2 , 2, 2 methylphosphonate , ethyl n -propyl methylphosphonate , trifluoroethyl) ( 2 , 2 , 2 - trifluoroethyl) phosphonate , diperfluo cyclohexyl ethyl methylphosphonate , ethyl methyl ethyl roethyl perfluoroethylphosphonate , di ( 2 - fluorocyclohexyl) phosphonate , methyl n -propyl ethylphosphonate, n -butyl ( 2 - fluorocyclohexyl) phosphonate , di( 3 - fluorocyclohexyl) methyl ethylphosphonate , cyclopentyl methyl ethylphos (3 - fluorocyclohexyl) phosphonate , di (4 - fluorocyclohexyl) phonate , cyclohexylmethyl ethylphosphonate , ethyl n -pro - 25 (4 -fluorocyclohexyl ) phosphonate , pyl ethylphosphonate , cyclohexyl ethyl ethylphosphonate , dimethyl (2 , 2 ,2 - trifluoroethyl) phosphonate , diethyl ( 2 ,2 ,2 ethyl methyl n -propylphosphonate , methyl n -propyl n -pro trifluoroethyl) phosphonate , di- n -butyl ( 2 , 2 ,2 -trifluoroethyl ) pylphosphonate , n -butyl methyl n -propylphosphonate , phosphonate , dicyclohexyl ( 2 ,2 ,2 - trifluoroethyl) phospho cyclopentyl methyl n -propylphosphonate , cyclohexyl nate , diperfluoroethyl ( 2 , 2 , 2 - trifluoroethyl) phosphonate , methyl n - propylphosphonate , ethyl n -propyl n - propylphos - 30 di( 2 - fluorocyclohexyl) ( 2 , 2 , 2 - trifluoroethyl ) phosphonate , phonate , cyclohexyl ethyl n - propylphosphonate , ethyl ethyl methyl ( 2 , 2 , 2 - trifluoroethyl ) phosphonate , n -butyl methyl n -butylphosphonate , methyl n -propyl n -butylphos methyl ( 2 , 2 , 2 - trifluoroethyl) phosphonate , cyclohexyl phonate , n -butyl methyl n - butylphosphonate , cyclopentyl methyl ( 2 , 2 , 2 -trifluoroethyl ) phosphonate , methyl ( 2 , 2 , 2 -tri methyl n -butylphosphonate , cyclohexyl methyl n - butyl - fluoroethyl) ( 2 , 2 , 2 - trifluoroethyl) phosphonate , methyl per phosphonate , ethyl n - propyl n -butylphosphonate , cyclo - 35 fluoroethyl ( 2 , 2 , 2 - trifluoroethyl) phosphonate , ( 2 - fluorocy hexyl ethyl n -butylphosphonate , clohexyl ) methyl ( 2 , 2 , 2 - trifluoroethyl )phosphonate , ethyl methyl cyclohexylphosphonate, methyl n -propyl cyclohexyl ethyl ( 2 , 2 , 2 - trifluoroethyl) phosphonate , ethyl cyclohexylphosphonate , n - butyl methyl cyclohexylphos ( 2 , 2 , 2 - trifluoroethyl) ( 2 , 2 , 2 - trifluoroethyl) phosphonate , phonate , cyclopentylmethyl cyclohexylphosphonate , cyclo - cyclohexyl ( 2 , 2 , 2 - trifluoroethyl) ( 2 , 2 , 2 - trifluoroethyl ) phos hexyl methyl cyclohexylphosphonate , ethyl n - propyl cyclo - 40 phonate , dimethyl (2 - fluorocyclohexyl) phosphonate , diethyl hexylphosphonate , cyclohexyl ethyl ( 2 - fluorocyclohexyl) phosphonate , dicyclohexyl ( 2 - fluoro cyclohexylphosphonate , diperfluoromethyl methylphospho - cyclohexyl) phosphonate , bis ( 2 , 2 , 2 -trifluoroethyl ) ( 2 - fluoro nate , di( 2 , 2 , 2 -trifluoroethyl ) methylphosphonate , diperfluo cyclohexyl) phosphonate , ethyl methyl ( 2 - fluorocyclohexyl ) roethyl methylphosphonate , di( 2 - fluorocyclohexyl) methyl phosphonate , cyclohexyl methyl ( 2 - fluorocyclohexyl) phosphonate , di( 3 - fluorocyclohexyl) methylphosphonate , 45 phosphonate , and methyl ( 2 , 2 , 2 - trifluoroethyl) ( 2 di( 4 - fluorocyclohexyl) methylphosphonate , diperfluorom fluorocyclohexyl )phosphonate . ethyl ethylphosphonate , di( 2 , 2 ,2 ,- trifluoroethyl ) ethylphos- Preferred of the phosphonic acid esters enumerated above phonate , diperfluoroethyl ethylphosphonate , di( 2 - fluorocy are clohexyl) ethylphosphonate, di( 3 - fluorocyclohexyl) dimethyl methylphosphonate , diethyl ethylphosphonate , di ethylphosphonate , di( 4 - fluorocyclohexyl) ethylphosphonate , 50 n -propyl n -propylphosphonate , di- n -butyl n -butylphospho di( 2 , 2 , 2 -trifluoroethyl ) n - propylphosphonate , diperfluoro - nate , diisobutyl isobutylphosphonate , diethyl methylphos ethyl n -propylphosphonate , di( 2, 2 ,2 - trifluoroethyl) n -butyl - phonate , di- n -butyl methylphosphonate , dimethyl phosphonate , diperfluoroethyl n -butylphosphonate , di( 2 , 2 , 2 ethylphosphonate , di- n - propyl ethylphosphonate , dimethyl trifluoroethyl) cyclohexylphosphonate, diperfluoroethyl n -propylphosphonate , diethyl n -propylphosphonate , di( 2 , 2 , cyclohexylphosphonate , 55 2 - trifluoroethyl) methylphosphonate , di( 2 , 2, 2 -trifluoroethyl ) methyl perfluoromethyl methylphosphonate , methyl (2 ,2 , 2 - ethylphosphonate , diperfluoromethyl perfluoromethylphos trifluoroethyl) methylphosphonate , methyl perfluoroethyl phonate , di( 2 , 2 , 2 - trifluoroethyl) ( 2 , 2 , 2 - trifluoroethyl) phos methylphosphonate , ( 2 - fluorocyclohexyl) methyl methyl phonate, diperfluoroethyl perfluoroethylphosphonate , dim phosphonate , (3 - fluorocyclohexyl)methyl methylphospho - ethyl ( 2 ,2 , 2 -trifluoroethyl ) phosphonate , and diethyl (2 , 2, 2 nate , ( 4 - fluorocyclohexyl) methyl methylphosphonate , ethyl 60 trifluoroethyl) phosphonate . perfluoroethyl methylphosphonate , cyclohexyl ( 2 , 2 , 2 - trif - Examples of the compound in which any two of R ', R², luoroethyl )methylphosphonate , cyclohexyl perfluoroethyl and Rºare alkyl groups and any one of these is an alkoxy methylphosphonate , perfluoroethyl ( 2 , 2 , 2 - trifluoroethyl) group include methylphosphonate , ethyl ( 2 , 2 , 2 -trifluoroethyl ) ethylphos methyl dimethylphosphinate , ethyl diethylphosphinate , phonate , ethyl perfluoroethyl ethylphosphonate , cyclohexyl 65 n -propyl di- n -propylphosphinate , isopropyl diisopropyl ( 2 , 2 , 2 - trifluoroethyl ) ethylphosphonate , cyclohexyl perfluo - phosphinate , n - butyl di- n -butylphosphinate , isobutyl roethyl ethylphosphonate , perfluoroethyl ( 2 , 2 , 2 - trifluoro - diisobutylphosphinate , tert -butyl di- tert -butylphosphinate , US 9 ,853 , 326 B2 85 86 cyclopentyl dicyclopentylphosphinate , cyclohexyl dicyclo - phosphinate , cyclohexyl n -butyl ( 2 , 2 , 2 -trifluoroethyl ) hexylphosphinate , methyl diethylphosphinate , methyl di- n - phosphinate , cyclohexyl cyclohexyl( 2 , 2 , 2 -trifluoroethyl ) propylphosphinate , methyl diisopropylphosphinate , methyl phosphinate , ( 2 , 2 , 2 - trifluoroethyl) ethylmethylphosphinate , di- n -butylphosphinate , methyl diisobutylphosphinate , ( 2 , 2 , 2 - trifluoroethyl) methyl - n -butylphosphinate , ( 2 , 2 , 2 -trif methyl di- tert- butylphosphinate , methyl dicyclopentylphos- 5 luoroethyl) cyclohexylmethylphosphinate, ( 2 , 2 , 2 - trifluoro phinate , methyl dicyclohexylphosphinate , ethyl dimethyl ethyl) methyl ( 2 , 2 , 2 - trifluoroethyl )phosphinate , ( 2 , 2 , 2 - trif phosphinate , ethyl di- n -propylphosphinate , ethyl diisopro - luoroethyl) n -butylethylphosphinate , ( 2 ,2 , 2 - trifluoroethyl) pylphosphinate , ethyl di - n -butylphosphinate , ethyl cyclohexylethylphosphinate , ( 2 , 2, 2 - trifluoroethyl) ethyl( 2 ,2 , diisobutylphosphinate , ethyl di- tert -butylphosphinate , ethyl 2 - trifluoroethyl) phosphinate , ( 2, 2 ,2 - trifluoroethyl) dicyclopentylphosphinate , ethyl dicyclohexylphosphinate , 10 n -butylcyclohexylphosphinate , ( 2 , 2 , 2 - trifluoroethyl ) n -butyl n -propyl dimethylphosphinate , n -propyl diethylphosphinate , ( 2 ,2 , 2 - trifluoroethyl) phosphinate , ( 2 , 2 , 2 - trifluoroethyl) n -propyl diisopropylphosphinate , n -propyl di- n -butylphos cyclohexyl( 2 , 2 , 2 - trifluoroethyl) phosphinate , and (2 , 2 ,2 - trif phinate , n - propyl diisobutylphosphinate , n - propyl di- tert luoroethyl) ( 2 , 2 , 2 - trifluoroethyl) phenylphosphinate , and the butylphosphinate , n -propyl dicyclopentylphosphinate , like . n -propyl dicyclohexylphosphinate , n -butyl dimethylphos- 15 Preferred of the phosphinic acid esters enumerated above phinate , n - butyl diethylphosphinate , n - butyl dicyclohexyl - are phosphinate , cyclohexyl dimethylphosphinate , cyclohexyl methyl dimethylphosphinate , ethyl diethylphosphinate , diethylphosphinate, cyclohexyl di- n -propylphosphinate , n -propyl di- n -propylphosphinate , n - butyl di- n -butylphos cyclohexyl di- n -butylphosphinate , methyl ethylmethylphos phinate , methyl diethylphosphinate , ethyl dimethylphosphi phinate , methyl methyl- n -propylphosphinate , methyl n -bu - 20 nate , perfluoromethyl bisperfluoromethylphosphinate, ( 2 ,2 , tylmethylphosphinate , methyl cyclohexylmethylphosphi- 2 -trifluoroethyl ) bis ( 2 , 2 , 2 - trifluoroethyl) phosphonate , nate , methyl ethyl- n - propylphosphinate , methyl perfluoroethyl bisperfluoroethylphosphinate , methyl bisper n -butylethylphosphinate , methyl cyclohexylethylphosphi fluoromethylphosphinate , methyl bis (2 ,2 , 2 -trifluoroethyl ) nate , methyl cyclohexyl- n -propylphosphinate , methyl n -bu phosphinate , methyl bisperfluoroethylphosphinate , ethyl tylcyclohexylphosphinate , ethyl ethylmethylphosphinate , 25 bisperfluoromethylphosphinate , ethyl bis ( 2 ,2 , 2 -trifluoro ethyl methyl - n - propylphosphinate , ethyl n -butylmethyl - ethyl) phosphinate , ethyl bisperfluoroethylphosphinate , ( 2 ,2 , phosphinate , ethyl cyclohexylmethylphosphinate , ethyl 2 -trifluoroethyl ) dimethylphosphinate , ( 2 , 2 , 2 -trifluoroethyl ) n -butylethylphosphinate , ethyl cyclohexylethylphosphinate , diethylphosphinate , and the like . ethyl n - butylcyclohexylphosphinate , n -butyl ethylmethyl- Examples of the compound in which all of R1 , R2 , and R3 phosphinate , n -butyl methyl- n - butylphosphinate , n - butyl 30 are alkyl groups include cyclohexylmethylphosphinate , n -butyl methylphenylphos trimethylphosphine oxide, triethylphosphine oxide , tri - n phinate , n -butyl n -butylethylphosphinate , n -butyl cyclo - propylphosphine oxide , triisopropylphosphine oxide, tri -n hexylethylphosphinate , n -butyl ethylphenylphosphinate , butylphosphine oxide, triisobutylphosphine oxide , tri - tert n -butyl n - butylcyclohexylphosphinate , n -butyl cyclohexyl butylphosphine oxide , tricyclopentylphosphine oxide , vinylphosphinate , cyclohexyl ethylmethylphosphinate , 35 tricyclohexylphosphine oxide , ethyldimethylphosphine cyclohexyl methyl- n -butylphosphinate , cyclohexyl cyclo oxide , dimethyl- n -propylphosphine oxide, isopropyldimeth hexylmethylphosphinate , cyclohexyl n - butylethylphosphi ylphosphine oxide, n -butyldimethylphosphine oxide, isobu nate , cyclohexyl cyclohexylethylphosphinate , cyclohexyl tyldimethylphosphine oxide, tert- butyldimethylphosphine n -butylcyclohexylphosphinate , perfluoromethyl bisperfluo - oxide, cyclopentyldimethylphosphine oxide, cyclohex romethylphosphinate , ( 2 , 2 , 2 -trifluoroethyl ) bis ( 2 , 2 , 2 -trif - 40 yldimethylphosphine oxide , diethylmethylphosphine oxide, luoroethyl) phosphonate , perfluoroethyl bisperfluoroethyl- diethyl - n - propylphosphine oxide, diethyl- n - butylphosphine phosphinate , ( 2 - fluorocyclohexyl) di( 2 - fluorocyclohexyl ) oxide , cyclohexyldiethylphosphine oxide, methyldi - n - pro phosphinate , ( 3 - fluorocyclohexyl) di( 3 - fluorocyclohexyl ) pylphosphine oxide, ethyldi- n - propylphosphine oxide , phosphinate , ( 4 - fluorocyclohexyl) di (4 - fluorocyclohexyl ) cyclohexyldi- n - propylphosphine oxide , di- n - butylmethyl phosphinate , methyl bisperfluoromethylphosphinate , methyl 45 phosphine oxide , di- n -butylethylphosphine oxide, di- n -bu bis ( 2 , 2 ,2 - trifluoroethyl) phosphinate , methyl bisperfluoro - tylcyclohexylphosphine oxide, dicyclohexylmethylphos ethylphosphinate , methyl di( 2 - fluorocyclohexyl) phosphi phine oxide, dicyclohexylethylphosphine oxide , nate , methyl di( 3 - fluorocyclohexyl) phosphinate , methyl dicyclohexyl- n - propylphosphine oxide, n -butyldicyclohex di( 4 - fluorocyclohexyl) phosphinate , ethyl bisperfluorometh ylphosphine oxide, ethylmethyl- n -propylphosphine oxide , ylphosphinate , ethyl bis ( 2 , 2, 2 -trifluoroethyl ) phosphinate , 50 ethylmethylisopropylphosphine oxide , ethylmethyl- n -butyl ethyl bisperfluoroethylphosphinate , ethyl di( 2 - fluorocyclo phosphine oxide , ethylmethylisobutylphosphine oxide , eth hexyl) phosphinate , ethyl di( 3 - fluorocyclohexyl) phosphi - ylmethyl- tert- butylphosphine oxide, ethylmethylcyclopen nate, ethyl di( 4 - fluorocyclohexyl )phosphinate , n -butyl bis ( 2 , tylphosphine oxide , ethylmethylcyclohexylphosphine oxide , 2 , 2 - trifluoroethyl )phosphinate , cyclohexyl bis ( 2 , 2 , 2 n -butylmethyl - n - propylphosphine oxide, n -butylmethylcy trifluoroethyl) phosphinate , ( 2 , 2 , 2 -trifluoroethyl ) 55 clohexylphosphine oxide, cyclohexylmethyl( 2 , 2 , 2 - trifluoro dimethylphosphinate , ( 2 , 2 , 2 - trifluoroethyl) diethylphosphi ethyl) phosphine oxide , triperfluoromethylphosphine oxide , nate, ( 2, 2, 2 -trifluoroethyl ) di- n -butylphosphinate , (2 , 2 ,2 - tri- tri (2 ,2 , 2 - trifluoroethyl) phosphine oxide, triperfluoroethyl fluoroethyl) dicyclohexylphosphinate , ethyl methyl( 2 , 2 , 2 phosphine oxide , tri ( 2 - fluorocyclohexyl) phosphine oxide , trifluoroethyl) phosphinate , ethyl methyl( 2 - fluorophenyl) tri( 3 - fluorocyclohexyl) phosphine oxide , tri ( 4 - fluorocyclo phosphinate , ethyl ethyl( 2 ,2 ,2 - trifluoroethyl) phosphinate , 60 hexyl) phosphine oxide, perfluoromethyldimethylphosphine ethyl n -butyl ( 2 ,2 , 2 -trifluoroethyl ) phosphinate , ethyl cyclo oxide, ( 2 , 2 , 2 -trifluoroethyl )dimethylphosphine oxide, per hexyl( 2 , 2 , 2 - trifluoroethyl) phosphinate , n - butyl methyl( 2 , 2 , fluoroethyldimethylphosphine oxide , ( 2 - fluorocyclohexyl) 2 -trifluoroethyl ) phosphinate , n -butyl ethyl( 2 , 2 ,2 - trifluoro - dimethylphosphine oxide, (3 - fluorocyclohexyl) dimethyl ethyl) phosphinate , n -butyl n -butyl ( 2 , 2 ,2 - trifluoroethyl) phosphine oxide , (4 - fluorocyclohexyl) dimethylphosphine phosphinate , n -butyl cyclohexyl( 2 , 2 ,2 - trifluoroethyl) 65 oxide , diethyl( 2 ,2 , 2 -trifluoroethyl ) phosphine oxide, di- n -bu phosphinate , cyclohexyl methyl( 2 , 2 , 2 - trifluoroethyl ) tyl( 2 , 2 , 2 -trifluoroethyl ) phosphine oxide, dicyclohexyl( 2 , 2 , phosphinate , cyclohexyl ethyl( 2, 2 ,2 - trifluoroethyl) 2 -trifluoroethyl ) phosphine oxide, di( 2 ,2 ,2 - trifluoroethyl) US 9 ,853 , 326 B2 87 88 methylphosphine oxide , ethyl( 2 , 2 ,2 - trifluoroethyl) romethyl )difluorophosphate , (2 ,2 , 2 - trifluoroethyl) difluoro phosphine oxide , n -butyldi ( 2 , 2 , 2 - trifluoroethyl) phosphine phosphate , and (pentafluoroethyl )difluorophosphate , and the oxide, cyclohexyldi( 2 , 2 , 2 - trifluoroethyl) phosphine oxide , like . ethylmethylperfluoromethylphosphine oxide, ethylmethyl < 1- 2 -2 . Nitrile Compounds > ( 2 , 2 , 2 - trifluoroethyl ) phosphine oxide , ethylmethylperfluo - 5 The nitrile compounds are not particularly limited in the roethylphosphine oxide , ethylmethyl( 2 - fluorocyclohexyl) kind thereof so long as they are compounds having a nitrile phosphine oxide, ethylmethyl( 3 - fluorocyclohexyl) group in the molecule. The nitrile compounds may be phosphine oxide , ethylmethyl (4 - fluorocyclohexyl) compounds each having two or more nitrile groups per phosphine oxide , n -butylmethyl ( 2 ,2 , 2 - trifluoroethyl) molecule. Examples of the nitrile compounds include phosphine oxide , n - butylethyl- n -propylphosphine oxide , 10 mono -nitrile compounds such as acetonitrile , propionitrile , n -butylethylcyclohexylphosphine oxide, n -butylethyl ( 2 , 2 , 2 butyronitrile , isobutyronitrile, valeronitrile , isovaleronitrile , trifluoroethyl) phosphine oxide , cyclohexylethyl( 2 ,2 , 2 - trif - 2 -methylbutyronitrile , trimethylacetonitrile , hexanenitrile , luoroethyl )phosphine oxide, and n -butylcyclohexyl ( 2 , 2 , 2 cyclopentanecarbonitrile , cyclohexanecarbonitrile , acryloni trifluoroethyl) phosphine oxide , and the like . trile , methacrylonitrile , crotononitrile , 3 -methylcrotononi Preferred of the phosphine oxides enumerated above are 15 trile, 2 -methyl - 2 -butenenitrile , 2 -pentenenitrile , 2 -methyl - 2 trimethylphosphine oxide, triethylphosphine oxide , tri - n pentenenitrile , 3 -methyl - 2 -pentenenitrile , 2 -hexenenitrile , propylphosphine oxide , tri- n -butylphosphine oxide , ethyl- fluoroacetonitrile , difluoroacetonitrile , trifluoroacetonitrile , dimethylphosphine oxide , diethylmethylphosphine oxide, 2 - fluoropropionitrile , 3 - fluoropropionitrile , 2 ,2 -difluoropro triperfluoromethylphosphine oxide, tri ( 2 , 2 , 2 - trifluoroethyl) pionitrile , 2 , 3 -difluoropropionitrile , 3 , 3 - difluoropropioni phosphine oxide , triperfluoroethylphosphine oxide, and the 20 trile , 2 ,2 , 3 - trifluoropropionitrile , 3 ,3 , 3 - trifluoropropionitrile , like . and pentafluoropropionitrile , and the like ; Examples of the compound in which any one of R ', R ? , di- nitrile compounds such as malononitrile , succinonitrile , and R3 is a fluorine atom include 2 -methylsuccinonitrile , tetramethylsuccinonitrile , glutaroni dimethyl fluorophosphate , ethyl methyl fluorophosphate , trile , 2 -methylglutaronitrile , adiponitrile , fumaronitrile , and methyl n -propyl fluorophosphate , n -butyl methyl fluoro - 25 2 -methyleneglutaronitrile , and the like ; and phosphate , diethyl fluorophosphate , ethyl n - propyl fluoro - tetra - nitrile compounds such as tetracyanoethylene, and the phosphate , n -butyl ethyl fluorophosphate , di - n - propyl fluo - like . rophosphate , n -butyl n -propyl fluorophosphate , di- n -butyl Preferred of these are methyl fluorophosphate , cyclopentyl methyl fluorophos acetonitrile , propionitrile , butyronitrile , valeronitrile , croto phate , cyclopentyl ethyl fluorophosphate , cyclopentyl n -pro - 30 nonitrile , 3 -methylcrotononitrile , malononitrile , succinoni pyl fluorophosphate , cyclopentyl n -butyl fluorophosphate , trile, glutaronitrile , adiponitrile , fumaronitrile , and the like . dicyclopentyl fluorophosphate , cyclohexyl methyl fluoro < 1 - 2 -3 . Isocyanate Compounds > phosphate , cyclohexyl ethyl fluorophosphate , cyclohexyl The isocyanate compounds are not particularly limited in n - propyl fluorophosphate , cyclohexyl n -butyl fluorophos - the kind thereof so long as they are compounds having an phate , dicyclohexyl fluorophosphate , bis ( trifluoromethyl ) 35 isocyanate group in the molecule . The isocyanate com fluorophosphate , methyl (trifluoromethyl ) fluorophosphate , pounds may be compounds each having two or more iso ethyl ( trifluoromethyl) fluorophosphate , n -propyl ( trifluo cyanate groups per molecule . Examples of the isocyanate romethyl) fluorophosphate , bis ( 2 , 2 , 2 - trifluoroethyl) fluoro compounds include monoisocyanate compounds such as phosphate , methyl ( 2 , 2 , 2 - trifluoroethyl) fluorophosphate , methyl isocyanate , ethyl isocyanate , n -propyl isocyanate , ethyl ( 2, 2 ,2 - trifluoroethyl) fluorophosphate , n -propyl (2 ,2 , 2 - 40 isopropyl isocyanate , n -butyl isocyanate , t -butyl isocyanate , trifluoroethyl) fluorophosphate, ( 2 , 2 , 2 - trifluoroethyl) ( trif cyclopentyl isocyanate , cyclohexyl isocyanate , phenyl iso luoromethyl) fluorophosphate , bis (pentafluoroethyl ) fluoro - cyanate , vinyl isocyanate , and allyl isocyanate , and the like ; phosphate , methyl (pentafluoroethyl ) fluorophosphate , ethyl diisocyanate compounds such asmethane diisocyanate , 1, 2 (pentafluoroethyl ) fluorophosphate , n -propyl (pentafluoro ethane diisocyanate , 1 , 3 - propane diisocyanate , and 1 , 4 -di ethyl) fluorophosphate , ( pentafluoroethyl) ( trifluoromethyl) 45 cyanatobutane and the like; fluorophosphate , and (pentafluoroethyl ) ( 2 , 2 , 2 - trifluoro ester - group - containing isocyanate compounds such as ethyl) fluorophosphate and the like . methyl isocyanatoformate , ethyl isocyanatoformate , methyl Preferred of the monofluorophosphoric acid esters enu - isocyanatoacetate , ethyl isocyanatoacetate , n - propyl isocya merated above are natoacetate , methyl 3 - isocyanatopropionate , ethyl 3 - isocya dimethyl fluorophosphate , ethyl methyl fluorophosphate , 50 natopropionate , n - propyl 3 -isocyanatopropionate , methyl methyl n -propyl fluorophosphate , diethyl fluorophosphate , 2 - isocyanatopropionate , ethyl 2 - isocyanatopropionate , and ethyl n - propyl fluorophosphate , di- n -propyl fluorophos n -propyl 2 - isocyanatopropionate , and the like ; phate , bis ( trifluoromethyl) fluorophosphate , methyl ( trifluo silicon -containing isocyanate compounds such as isocyana romethyl) fluorophosphate , ethyl (trifluoromethyl ) fluoro totrimethylsilane , isocyanatotriethylsilane, isocyanatotri - n phosphate , n -propyl ( trifluoromethyl ) fluorophosphate , bis 55 propylsilane, isocyanatotrimethoxysilane, isocyanatotri ( 2 , 2 , 2 - trifluoroethyl) fluorophosphate , methyl ( 2 , 2 , 2 ethoxysilane , isocyanatotri - n -propoxysilane , trifluoroethyl) fluorophosphate , ethyl ( 2 ,2 , 2 - trifluoroethyl ) isocyanatomethyltrimethylsilane, isocyanatomethyltriethyl fluorophosphate , n -propyl ( 2 , 2 , 2 - trifluoroethyl ) silane , 2 -isocyanatoethyltrimethylsilane , 2 - isocyanatoethyl fluorophosphate , bis (pentafluoroethyl ) fluorophosphate , triethylsilane , 3 -isocyanatopropyltrimethylsilane , 3 -isocya methyl (pentafluoroethyl ) fluorophosphate , ethyl (pentafluo - 60 natopropyltriethylsilane , roethyl ) fluorophosphate , n -propyl (pentafluoroethyl ) fluoro isocyanatomethyltrimethoxysilane, isocyanatomethyltri phosphate , and the like . ethoxysilane , 2 - isocyanatoethyltrimethoxysilane, 2 - isocya Examples of the compound in which any two of R ' , R ? , natoethyltriethoxysilane , 3 - isocyanatopropyltrimethoxysi and Rare fluorine atoms include lane, and 3 - isocyanatopropyltriethoxysilane, and the like ; methyl difluorophosphate , ethyldifluorophosphate , n -propyl 65 and difluorophosphate, n -butyl difluorophosphate , cyclopentyl phosphorus - containing isocyanate compounds such as iso difluorophosphate , cyclohexyl difluorophosphate , ( trifluo cyanatodimethyl phosphate , isocyanatoethyl methyl phos US 9 ,853 , 326 B2 89 90 phate, isocyanatomethyl n -propyl phosphate , isocyanato -n - 3. Examples thereof include halogen atoms, alkyl groups , butyl methyl phosphate , isocyanatodiethyl phosphate , aryl groups , acyl groups , carboxy group , and groups repre isocyanatoethyl n -propyl phosphate , isocyanato - n -butyl sented by R - O (wherein R represents an alkyl group or ethyl phosphate , isocyanatodi- n -propyl phosphate , isocya - an aryl group ) (hereinafter suitably referred to as “ RO nato - n -butyl n -propyl phosphate , and isocyanatodi- n -butyl 5 groups” ) . Of these, halogen atoms or RO groups are pre methyl phosphate , and the like . ferred from the standpoint of electrochemical stability . The halogen atoms preferably are fluorine , chlorine , and Preferred of these are bromine atoms. Especially preferred is a fluorine atom . On methyl isocyanate , ethyl isocyanate , n - propyl isocyanate , the other hand , with respect to the RO groups , when R is an n -butyl isocyanate , methane diisocyanate , 1 ,2 -ethane diiso 10 alkyl group , preferred examples of R are alkyl groups having cyanate , 1 , 3 - propane diisocyanate , 1 , 4 - dicyanatobutane , 1 - 6 carbon atoms. Specific examples of such preferred alkyl methyl isocyanatoformate , ethyl isocyanatoformate , methyl groups represented by R include methyl, ethyl , n -propyl , and isocyanatoacetate , ethyl isocyanatoacetate , isocyanatotrim isopropyl. Especially preferred is methyl or ethyl . On the ethylsilane , isocyanatotriethylsilane, isocyanatotri - n -propyl other hand , when R is an aryl group , preferred examples silane, isocyanatotrimethoxysilane , isocyanatotriethoxysi, 15 thereof include phenyl, tolyl, and naphthyl. Especially pre lane, isocyanatotri - n - propoxysilane, isocyanatodimethyl ferred is phenyl. Incidentally , the hydrogen atoms possessed phosphate , isocyanatoethyl methyl phosphate , isocyanato by the alkyl group or aryl group represented by R may have diethyl phosphate , and the like . been replaced with halogen atoms. Replacement with fluo < 1 - 2 - 4 . Phosphazene Compounds > rine is especially preferred because this enhances electro The term “ phosphazene compounds ” in invention 3 20 chemical stability. Although all the substituents represented means compounds having a structural unit represented by by X may be of the same kind , the substituents may be a — PX " X " = N — (wherein Xa and X ” each independently combination of substituents of two or more different kinds . represent a monovalent substituent) . By the number of such In general formula ( 2 ) , n represents an integer of generally structural units and by the state in which the structural units from 3 to 10 , preferably 5 or smaller. In general formula ( 3 ) , are bonded , phosphazene compounds are classified into : 25 m represents an integer which is generally 0 or larger, and monophosphazenes constituted of only one structural unit of is generally 10 or smaller, preferably 3 or smaller . When n that kind ; cyclic phosphazenes constituted of structural units or m exceeds 10 , there are cases where incorporation of of that kind which have been bonded cyclicly ; polyphosp - these compounds into an electrolyte results in an increase in hazenes constituted of structural units of that kind which viscosity and hence in a decrease in conductivity and this have been bonded in an acyclic arrangement ; etc . The kinds 30 reduces battery performances including load characteristics. of phosphazene compounds are not particularly limited , and The molecular weights of the compounds respectively a compound falling under any of these groups can be used . represented by general formula ( 2 ) and general formula ( 3 ) However , it is preferred to use , among those compounds , a each are generally in the range of from 200 to 2 ,000 , cyclic phosphazene represented by the following general preferably to 1 ,000 . When the molecular weights thereof are formula ( 2 ) and / or an acyclic phosphazene represented by 35 too high , there are cases where a dissolution failure occurs the following general formula (3 ) . or an increase in higher viscosity results to impair load characteristics . < 1 - 2 - 5 . Disulfonic Acid Ester Compounds> [Chemical Formula - 5 ] The disulfonic acid ester compounds are not particularly 40 limited in the kind thereof so long as they are compounds having two sulfonic acid ester structures in the molecule . - - PEN Examples of acyclic disulfonic acid esters include - ethanediol disulfonates such as ethanediol dimethanesul fonate , ethanediol diethanesulfonate , ethanediol dipropane 45 sulfonate , ethanediol dibutanesulfonate , ethanediol bis ( trif luoromethanesulfonate ) , ethanediol ( pentafluoroethanesulfonate ), ethanediol [ In general formula (2 ), xll and X12 each independently (heptafluoropropanesulfonate ) , ethanediol represent a monovalent substituent. ] (perfluorobutanesulfonate ) , ethanediol 50 (perfluoropentanesulfonate ) , ethanediol bis (perfluorohexanesulfonate ) , ethanediol bis [ Chemical Formula - 6 ] ( perfluorooctanesulfonate ), ethanediol bis (perfluoro - 1 (3 ) methylethanesulfonate ), ethanediol bis ( perfluoro - 1 , 1 X22 dimethylethanesulfonate ), ethanediol bis (perfluoro - 3 55 methylbutanesulfonaten ) , ethanediol X21 — P = N - PENTP - X27 di( fluoromethanesulfonate ), ethanediol bis (difluorometh anesulfonate ) , ethanediol di( 2 - fluoroethanesulfonate ) , eth FHLX23 825 326 anediol bis ( 1 , 1 - difluoroethanesulfonate ), ethanediol bis ( 1 , 2 difluoroethanesulfonate ), ethanediol bis ( 2 , 2 [ In general formula ( 3 ) , X21 , X22 , X23 , X24 , X25 , X26, and 60 difluoroethanesulfonate ), ethanediol bis ( 1 , 1 , 2 X ? ' each independently represent a monovalent substituent. ] trifluoroethanesulfonate ), ethanediol bis ( 1 , 2 , 2 In the following statement, when Xll , X12, X21 , X22 , X23 , ethanediol bis ( 2 , 2 ,2 X24 , X5, X26, and X27 are referred to without being espe trifluoroethanesulfonate ), ethanediol bis ( 1 , 1 , 2 , 2 cially distinguished from each other, “ X ” is used for repre - tetrafluoroethanesulfonate ) , ethanediol bis ( 1 , 2 , 2 , 2 senting these . 65 tetrafluoroethanesulfonate ) , ethanediol di( 1 - fluoro - 1 The monovalent substituents are not particularly limited methylethanesulfonate ) , ethanediol bis ( 1 , 2 , 2 , 2 - tetrafluoro unless the substituents are counter to the spirit of invention 1 -methylethanesulfonate ), ethanediol bis ( 1 , 1 -difluoro - 2 US 9 ,853 , 326 B2 91 92 methylpropanesulfonate ), ethanediol bis ( 1 , 2 ,2 , 3 , 3 , 3 propanediol di ( 2 - fluoro - 1 - fluoromethylethanesulfonate ) , hexafluoro - 1 -methylpropanesulfonate ), ethanediol di( 2 - 1 ,3 -propanediol bis ( 2 ,2 ,2 - trifluoro - 1 - trifluoromethylethane fluoro - 1- fluoromethylethanesulfonate ), ethanediolbis (2 ,2 , 2 sulfonate ), 1 ,3 -propanediol bis ( 1- trifluoromethylethanesul trifluoro - 1 -trifluoromethylethanesulfonate ) , ethanediol bis fonate ) , 1 , 3 -propanediol di( 1 -methyl - 1 - trifluoromethyl ( 1 - trifluoromethylethanesulfonate ), ethanediol di( 1 -methyl - 5 ethanesulfoante ) , and 1 , 3 - propanediol bis ( 1 1 - trifluoromethylethanesulfoante ), and ethanediol bis ( 1 - trifluoromethylhexanesulfonate ) ; trifluoromethylhexanesulfonate ), and the like; 1 , 2 - butanediol disulfonates such as 1 , 2 -butanediol dimeth 1 ,2 -propanediol disulfonates such as 1, 2 -propanediol dime- anesulfonate , 1 ,2 -butanediol diethanesulfonate , 1, 2 -butane thanesulfonate , 1 , 2 - propanediol diethanesulfonate , 1 , 2 -pro - diol bis ( trifluoromethanesulfonate ) , 1 , 2 - butanediol bis ( pen panediol dipropanesulfonate , 1, 2 -propanediol dibutanesul- 10 tafluoroethanesulfonate ) , 1 , 2 - butanediol bis fonate , 1 , 2 -propanediol bis ( trifluoromethanesulfonate ), 1 , 2 (heptafluoropropanesulfonate ), 1 , 2 -butanediol bis propanediol bis (pentafluoroethanesulfonate ), 1 ,2 (perfluorobutanesulfonate ), 1 , 2 -butanediol bis (perfluoro - 1 propanediol bis (heptafluoropropanesulfonate ), 1, 2 methylethanesulfonate ), 1, 2 -butanediol bis (perfluoro - 1, 1 propanediol bis (perfluorobutanesulfonate ) , 1 , 2 -propanediol dimethylethanesulfonate ) , 1 , 2 -butanediol bis (perfluoropentanesulfonate ), 1 , 2 -propanediol bis ( perfluo - 15 di( fluoromethanesulfonate ), 1 , 2 -butanediol bis (difluo rohexanesulfonate ), 1 , 2 -propanediol bis (perfluorooctanesul romethanesulfonate ) , 1 , 2 -butanediol di( 2 - fluoroethanesul fonate ), 1, 2 -propanediol bis (perfluoro - 1 -methylethanesul fonate) , 1 ,2 -butanediol bis (2 , 2 -difluoroethanesulfonate ), fonate ), 1, 2 -propanediol bis (perfluoro - 1, 1 - 1, 2 -butanediol bis (2 ,2 ,2 - trifluoroethanesulfonate ), 1, 2 -bu dimethylethanesulfonate ), 1 , 2 -propanediol bis (perfluoro - 3 tanediol di( 1 - fluoro - 1 -methylethanesulfonate ), 1, 2 - butane methylbutanesulfonate ), 1 , 2 - propanediol 20 diol di ( 2 - fluoro - 1 - fluoromethylethanesulfonate ), 1 , 2 -bu di( fluoromethanesulfonate ), 1 , 2 - propanediol bis( difluo tanediol bis ( 2 , 2 , 2 - trifluoro - 1 romethanesulfonate ) , 1 , 2 -propanediol di( 2 - fluoroethanesul- trifluoromethylethanesulfonate ) , 1 , 2 -butanediol bis ( 1 fonate ) , 1 , 2 - propanediol bis ( 1 , 1 -difluoroethanesulfonate ), trifluoromethylethanesulfonate ) , 1 , 2 -butanediol di (1 1 , 2 - propanediol bis ( 1 , 2 - difluoroethanesulfonate ) , 1 , 2 - pro - methyl- 1 - trifluoromethylethanesulfonate ) , and 1 , 2 panediol bis ( 2 , 2 - difluoroethanesulfonate ), 1 , 2 - propanediol 25 butanediol bis ( 1 - trifluoromethylhexanesulfonate ) and the bis ( 1 , 1 ,2 - trifluoroethanesulfonate ), 1 ,2 -propanediol bis (1 , 2 , like ; 2 - trifluoroethanesulfonate ) , 1, 2 - propanediol bis ( 2 , 2 , 2 - trif - 1 , 3 -butanediol disulfonates such as 1 , 3 - butanediol dimeth luoroethanesulfonate ) , 1 , 2 - propanediol bis ( 1 , 1 , 2 , 2 -tetra anesulfonate , 1 , 3 -butanediol diethanesulfonate, 1 , 3 -butane fluoroethanesulfonate ), 1 , 2 - propanediol bis ( 1 , 2 , 2 , 2 - diol bis ( trifluoromethanesulfonate ), 1 , 3 -butanediol bis (pen tetrafluoroethanesulfonate ), 1, 2 -propanediol di( 1 - fluoro - 1 - 30 tafluoroethanesulfonate) , 1, 3 -butanediol bis methylethanesulfonate ), 1, 2 -propanediol bis ( 1, 2 ,2 , 2 - (heptafluoropropanesulfonate ), 1, 3 -butanediol bis tetrafluoro - 1 -methylethanesulfonate ), 1 , 2 -propanediol bis ( 1 , ( perfluorobutanesulfonate ), 1 , 3 - butanediol bis ( perfluoro - 1 1 -difluoro - 2 -methylpropanesulfonate ), 1, 2 -propanediol bis methylethanesulfonate ), 1, 3 -butanediol bis (perfluoro - 1, 1 ( 1 , 2 , 2 , 3 , 3 , 3 -hexafluoro - 1 -methylpropanesulfonate ) , 1 , 2 dimethylethanesulfonate ) , 1, 3 -butanediol propanediol di ( 2 - fluoro - 1 - fluoromethylethanesulfonate ), 35 di( fluoromethanesulfonate ), 1 , 3 -butanediol bis ( difluo 1 , 2 - propanediol bis ( 2 , 2 , 2 - trifluoro - 1 - trifluoromethylethane - romethanesulfonate ), 1 , 3 - butanediol di ( 2 - fluoroethanesul sulfonate ) , 1 , 2 -propanediol bis( 1 - trifluoromethylethanesul- fonate ), 1 , 3 -butanediol bis( 2 , 2 - difluoroethanesulfonate ) , fonate ) , 1 , 2 -propanediol di( 1 -methyl - 1 -trifluoromethyl 1 , 3 -butanediol bis ( 2 , 2 , 2 - trifluoroethanesulfonate ), 1 , 3 -bu ethanesulfoante ) , and 1 , 2 -propanediol bis ( 1 - tanediol di ( 1 - fluoro - 1 -methylethanesulfonate ) , 1 , 3 - butane trifluoromethylhexanesulfonate ) , and the like ; 40 diol di ( 2 - fluoro - 1 - fluoromethylethanesulfonate ) , 1 , 3 - bu 1 , 3 -propanediol disulfonates such as 1 , 3 -propanediol dime tanediol bis ( 2 , 2 , 2 - trifluoro - 1 thanesulfonate , 1 , 3 -propanediol diethanesulfonate , 1 , 3 -pro - trifluoromethylethanesulfonate ) , 1 , 3 -butanediol bis[ ( 1 panediol dipropanesulfonate , 1, 3 -propanediol dibutanesul trifluoromethyl) ethanesulfonate ], 1, 3 -butanediol di( 1 fonate , 1 ,3 -propanediol bis (trifluoromethanesulfonate ), 1, 3 methyl- 1 - trifluoromethylethanesulfonate ), and 1 ,3 propanediol bis ( pentafluoroethanesulfonate ), 1, 3 - 45 butanediol bis ( 1 - trifluoromethylhexanesulfonate ) and the propanediol bis (heptafluoropropanesulfonate ), 1 , 3 - like ; propanediol bis (perfluorobutanesulfonate ) , 1 , 3 - propanediol 1 , 4 -butanediol disulfonates such as 1 , 4 - butanediol dimeth bis (perfluoropentanesulfonate ), 1 , 3 - propanediol bis (perfluo anesulfonate , 1 , 4 -butanediol diethanesulfonate , 1 , 4 -butane rohexanesulfonate ), 1 , 3 -propanediol bis (perfluorooctanesul - diol dipropanesulfonate , 1 , 4 -butanediol dibutanesulfonate , fonate ), 1 , 3 - propanediol bis (perfluoro - 1 -methylethanesul - 50 1 , 4 - butanediol bis (trifluoromethanesulfonate ), 1 , 4 - butane fonate ) , 1 , 3 - propanediol bis (perfluoro - 1 , 1 - diol bis ( pentafluoroethanesulfonate ), 1 , 4 - butanediol bis dimethylethanesulfonate ), 1 , 3 - propanediol bis( perfluoro - 3 - (heptafluoropropanesulfonate ) , 1 , 4 -butanediol bis (perfluo methylbutanesulfonate ), 1 , 3 - propanediol robutanesulfonate ) , 1 , 4 -butanediol bis di( fluoromethanesulfonate ), 1 , 3 -propanediol bis ( difluo - ( perfluoropentanesulfonate ), 1 , 4 -butanediol bis romethanesulfonate ) , 1 , 3 -propanediol di( 2 - fluoroethanesul- 55 (perfluorohexanesulfonate ), 1 , 4 - butanediol bis fonate ), 1 , 3 -propanediol bis ( 1 , 1 -difluoroethanesulfonate ), (perfluorooctanesulfonate ), 1 ,4 -butanediol bis (perfluoro - 1 1 , 3 -propanediol bis ( 1 , 2 - difluoroethanesulfonate ) , 1 , 3 -pro - methylethanesulfonate ), 1 , 4 -butanediol bis ( perfluoro - 1 , 1 panediol bis ( 2 , 2 -difluoroethanesulfonate ) , 1 , 3 -propanediol dimethylethanesulfonate ) , 1 , 4 -butanediol bis (perfluoro - 3 bis ( 1 , 1 , 2 - trifluoroethanesulfonate ) , 1 , 3 -propanediol bis ( 1 , 2 , methylbutanesulfonate ) , 1 , 4 -butanediol 2 -trifluoroethanesulfonate ), 1 , 3 -propanediol bis ( 2 , 2 , 2 - trif - 60 di( fluoromethanesulfonate ), 1 , 4 -butanediol bis (difluo luoroethanesulfonate ) , 1 , 3 -propanediol bis ( 1 , 1 , 2 , 2 - tetra romethanesulfonate ) , 1 , 4 -butanediol di( 2 - fluoroethanesul fluoroethanesulfonate ) , 1 , 3 - propanediol bis ( 1 , 2 , 2 , 2 - fonate ) , 1 , 4 - butanediol bis ( 1 , 1 - difluoroethanesulfonate ) , tetrafluoroethanesulfonate ) , 1 , 3 -propanediol di( 1 - fluoro - 1 - 1 , 4 - butanediol bis ( 1 , 2 -difluoroethanesulfonate ) , 1 , 4 -butane methylethanesulfonate ) , 1 , 3 - propanediol bis ( 1 , 2 , 2 , 2 diol bis ( 2 ,2 - difluoroethanesulfonate ), 1 , 4 -butanediol bis ( 1 , tetrafluoro - 1 -methylethanesulfonate ) , 1 ,3 -propanediol bis ( 1, 65 1 ,2 - trifluoroethanesulfonate ), 1, 4 -butanediol bis ( 1, 2 ,2 -trif 1 -difluoro - 2 -methylpropanesulfonate ), 1 , 3 -propanediol bis l uoroethanesulfonate ), 1 , 4 -butanediol bis ( 2 ,2 , 2 ( 1, 2 ,2 ,3 , 3 ,3 -hexafluoro - 1- methylpropanesulfonate ), 1, 3 - trifluoroethanesulfonate ), 1, 4 - butanediol bis (1 ,1 , 2 , 2 US 9 ,853 , 326 B2 93 94 tetrafluoroethanesulfonate ), 1, 4 -butanediol bis (1 ,2 ,2 , 2 1 , 3 -butanediol disulfonates such as 1 , 3 -butanediol dimeth tetrafluoroethanesulfonate ), 1 , 4 -butanediol di( 1 - fluoro - 1 anesulfonate , 1 , 3 - butanediol diethanesulfonate , 1 , 3 -butane methylethanesulfonate ), 1 , 4 -butanediol bis ( 1 , 2 , 2 , 2 diol bis ( trifluoromethanesulfonate ), 1 , 3 -butanediol bis ( pen tetrafluoro - 1 -methylethanesulfonate ) , 1, 4 -butanediol bis ( 1 , tafluoroethanesulfonate ) , 1 , 3 -butanediol 1 -difluoro - 2 -methylpropanesulfonate ), 1, 4 -butanediol bis ( 1, 5 di( fluoromethanesulfonate ), 1, 3 -butanediol bis (difluo 2 , 2 , 3 , 3 , 3 - hexafluoro - 1 -methylpropanesulfonate ), 1 , 4 romethanesulfonate ), 1 , 3 -butanediol di( 2 - fluoroethanesul butanediol di( 2 - fluoro - 1 - fluoromethylethanesulfonate ), 1 , 4 - fonate ), 1 , 3 -butanediol bis ( 2 , 2 - difluoroethanesulfonate ) , butanediol bis ( 2, 2 ,2 - trifluoro - 1 - and 1 , 3 -butanediol bis (2 , 2 ,2 - trifluoroethanesulfonate ) and trifluoromethylethanesulfonate ) , 1 , 4 -butanediol bis ( 1 the like ; and trifluoromethylethanesulfonate ) , 1 , 4 -butanediol di( 1 - 10 1 , 4 - butanediol disulfonates such as 1 , 4 -butanediol dimeth methyl- 1 - trifluoromethylethanesulfoante ) , and 1 , 4 - anesulfonate , 1 , 4 -butanediol diethanesulfonate , 1 , 4 -butane butanediol bis ( 1 - trifluoromethylhexanesulfonate ), and the diol bis (trifluoromethanesulfonate ), 1, 4 -butanediol bis (pen like ; and tafluoroethanesulfonate ), 1, 4 -butanediol 1 , 4 -benzenediol disulfonates such as 1 , 4 -benzenediol dime - di( fluoromethanesulfonate ) , 1 , 4 -butanediol bis (difluo thanesulfonate , 1 , 4 -benzenediol diethanesulfonate , 1 , 4 - ben - 15 romethanesulfonate ), 1 ,4 -butanediol di( 2 - fluoroethanesul zenediol bis ( trifluoromethanesulfonate ) , 1 , 4 -benzenediol bis fonate) , 1 , 4 -butanediol bis ( 2 , 2 - difluoroethanesulfonate ) , (pentafluoroethanesulfonate ), 1 ,4 -benzenediol bis and 1, 4 -butanediol bis (2 ,2 , 2 - trifluoroethanesulfonate ) and (heptafluoropropanesulfonate ), 1, 4 -benzenediol bis the like . ( perfluorobutanesulfonate ), 1 , 4 - benzenediol bis( perfluoro - Especially preferred of these are 1 -methylethanesulfonate ) , 1 , 4 -benzenediol bis ( perfluoro - 1 , 20 ethanediol disulfonates such as ethanediol bis ( trifluorometh 1 - dimethylethanesulfonate ) , 1 , 4 -benzenediol a nesulfonate ) , ethanediol bis ( pentafluoroethanesulfonate ) , di( fluoromethanesulfonate ) , 1 , 4 -benzenediol di( 2 - fluoroeth - ethanediol di( fluoromethanesulfonate ) , ethanediol di ( 2 - fluo anesulfonate ), 1 , 4 -benzenediol bis ( 2 ,2 - difluoroethanesul roethanesulfonate ), and ethanediol bis ( 2 , 2 , 2 - trifluoroeth fonate ) , 1 , 4 -benzenediol bis ( 2 , 2 , 2 - trifluoroethanesulfonate ) , anesulfonate ) and the like ; 1 , 4 -benzenediol di( 1 - fluoro - 1 -methylethanesulfonate ) , 1 , 4 - 25 1 , 2 - propanediol disulfonates such as 1 , 2 - propanediol bis benzenediol di( 2 - fluoro - 1 - fluoromethylethanesulfonate ), ( trifluoromethanesulfonate ), 1 , 2 -propanediol bis (pentafluo 1 , 4 -benzenediol bis ( 2 , 2 , 2 - trifluoro - 1 - trifluoromethylethane - roethanesulfonate ) , 1 , 2 - propanediol di ( fluoromethanesul sulfonate ) , 1 , 4 -benzenediol bis ( 1 -trifluoromethylethanesul fonate ) , 1 , 2 - propanediol di( 2 - fluoroethanesulfonate ) , and fonate ), 1 , 4 -benzenediol di ( 1 -methyl - 1 - trifluoromethyl 1 , 2 -propanediol bis ( 2 , 2 , 2 - trifluoroethanesulfonate ) and the ethanesulfonate ) , and 1 , 4 -benzenediol bis ( 1 - 30 like ; trifluoromethylhexanesulfonate ) and the like . 1 , 3 -propanediol disulfonates such as 1 , 3 -propanediol bis Preferred of these are ( trifluoromethanesulfonate ), 1 ,3 -propanediol bis (pentafluo ethanediol disulfonates such as ethanediol dimethanesul- roethanesulfonate ), 1, 3 -propanediol di( 2 - fluoroethanesul fonate , ethanediol diethanesulfonate , ethanediol bis (trifluo - fonate ) , and 1 , 3 -propanediol bis ( 2 , 2 , 2 romethanesulfonate ) , ethanediol bis (pentafluoroethanesul - 35 trifluoroethanesulfonate ) and the like; fonate ), ethanediol di( fluoromethanesulfonate ) , ethanediol 1, 2 -butanediol disulfonates such as 1, 2 -butanediol bis ( trif bis ( difluoromethanesulfonate ) , ethanediol di ( 2 - fluoroeth - luoromethanesulfonate ), 1 , 2 -butanediol bis (pentafluoroeth anesulfonate ) , ethanediol bis ( 2 , 2 - difluoroethanesulfonate ) , anesulfonate ), 1 , 2 -butanediol di( fluoromethanesulfonate ) , and ethanediol bis ( 2 , 2 ,2 - trifluoroethanesulfonate ) and the 1 , 2 -butanediol di( 2 - fluoroethanesulfonate ) , and 1 ,2 -butane like; 40 diol bis ( 2 ,2 , 2 - trifluoroethanesulfonate ) and the like ; 1 , 2 -propanediol disulfonates such as 1 , 2 - propanediol dime- 1 , 3 -butanediol disulfonates such as 1 , 3 -butanediol bis ( trif thanesulfonate , 1 , 2 -propanediol diethanesulfonate , 1 , 2 -pro - luoromethanesulfonate ) , 1 , 3 -butanediol bis (pentafluoroeth panediolbis ( trifluoromethanesulfonate ) , 1 , 2 - propanediolbis anesulfonate ), 1 , 3 -butanediol di( fluoromethanesulfonate ) , (pentafluoroethanesulfonate ), 1 , 2 - propanediol 1 , 3 -butanediol di( 2 - fluoroethanesulfonate ) , and 1 , 3 -butane di( fluoromethanesulfonate ), 1 , 2 -propanediol bis ( difluo - 45 diol bis ( 2 , 2 , 2 - trifluoroethanesulfonate ) and the like ; and romethanesulfonate ) , 1 , 2 -propanediol di( 2 - fluoroethanesul - 1 , 4 -butanediol disulfonates such as 1 , 4 -butanediol bis( trif fonate ), 1, 2 - propanediol bis ( 2 , 2 -difluoroethanesulfonate ), luoromethanesulfonate ), 1 , 4 -butanediol bis (pentafluoroeth and 1 , 2 -propanediol bis ( 2 , 2 , 2 - trifluoroethanesulfonate ) , and anesulfonate ) , 1 , 4 -butanediol di ( fluoromethanesulfonate ) , the like ; 1 , 4 -butanediol di ( 2 - fluoroethanesulfonate ) , and 1 , 4 -butane 1 , 3 - propanediol disulfonates such as 1 , 3 -propanediol dime- 50 diol bis ( 2 , 2 , 2 -trifluoroethanesulfonate ) and the like . thanesulfonate , 1 , 3 - propanediol diethanesulfonate , 1 , 3 -pro - Examples of cyclic disulfonic acid esters include panediol bis ( trifluoromethanesulfonate ) , 1 , 3 -propanediol bis 1 , 5 , 2 , 4 - dioxadithiane - 2 , 2 ,4 , 4 -tetraoxide , 3 -methyl - 1 , 5 , 2 , 4 ( pentafluoroethanesulfonate ), 1 , 3 -propanediol dioxadithiane - 2 , 2 , 4 , 4 - tetraoxide , 3 , 3 - dimethyl- 1 , 5 , 2 , 4 - di di( fluoromethanesulfonate ), 1 , 3 -propanediol bis ( difluo - oxadithiane - 2 , 2 , 4 , 4 - tetraoxide , 3 - fluoro - 1 , 5 , 2 , 4 -dioxadithi romethanesulfonate ), 1 , 3 -propanediol di( 2 - fluoroethanesul- 55 ane - 2 , 2 , 4 , 4 - tetraoxide, 3 , 3 - difluoro - 1 , 5 , 2 , 4 -dioxadithiane - 2 , fonate ), 1, 3 -propanediol bis ( 2 , 2 -difluoroethanesulfonate ) , 2 , 4 , 4 - tetraoxide , 6 -methyl - 1 , 5 ,2 , 4 - dioxadithiane- 2 , 2 , 4 ,4 and 1, 3 -propanediol bis (2 ,2 ,2 - trifluoroethanesulfonate ) and tetraoxide , 6 ,6 -dimethyl - 1, 5 , 2 ,4 -dioxadithiane - 2 ,2 ,4 , 4 the like ; tetraoxide, 6 - fluoro - 1 , 5 , 2 , 4 -dioxadithiane - 2 , 2 , 4 , 4 1 , 2 -butanediol disulfonates such as 1 , 2 -butanediol dimeth - tetraoxide , 6 ,6 - difluoro - 1 , 5 , 2 , 4 - dioxadithiane - 2 , 2 , 4 , 4 anesulfonate , 1 , 2 - butanediol diethanesulfonate , 1 , 2 -butane - 60 tetraoxide , 3 , 6 - dimethyl - 1 , 5 , 2 ,4 - dioxadithiane - 2 , 2 , 4 , 4 diol bis ( trifluoromethanesulfonate ), 1, 2 -butanediol bis( pen tetraoxide , 3 , 6 -difluoro - 1 , 5 ,2 , 4 - dioxadithiane- 2 , 2 , 4 ,4 tafluoroethanesulfonate ) , 1 , 2 -butanediol tetraoxide, 3 ,3 ,6 ,6 - tetramethyl- 1 ,5 , 2, 4 -dioxadithiane -2 , 2, 4 , di( fluoromethanesulfonate ), 1 , 2 -butanediol bis ( difluo 4 - tetraoxide, 3 , 3 ,6 , 6 - tetrafluoro - 1 , 5 , 2 , 4 -dioxadithiane - 2 , 2 , romethanesulfonate ) , 1 , 2 -butanediol di ( 2 - fluoroethanesul 4 , 4 -tetraoxide , fonate ) , 1 , 2 - butanediol bis ( 2 , 2 - difluoroethanesulfonate ), 65 1 , 4 ,2 , 5 - dioxadithiane - 2 , 2 ,5 , 5 - tetraoxide, 3 -methyl - 1 , 4 ,2 , 5 and 1 ,2 -butanediol bis (2 ,2 , 2 - trifluoroethanesulfonate ) and dioxadithiane - 2 ,2 ,5 , 5 -tetraoxide , 3 ,3 -dimethyl - 1 ,4 , 2 ,5 - di the like ; oxadithiane - 2 ,2 , 5 ,5 - tetraoxide , 3 - fluoro - 1 , 4 , 2 , 5 - dioxadithi US 9 ,853 , 326 B2 95 96 ane - 2 , 2 , 5 , 5 -tetraoxide , 3 , 3 - difluoro - 1 , 4 , 2 , 5 - dioxadithiane - 2 , methyl phenyl sulfide , methyl (2 - tolyl) sulfide , methyl 2 ,5 , 5 - tetraoxide, 3 ,6 -dimethyl - 1 , 4, 2, 5 -dioxadithiane - 2 ,2 , 5 , ( 3 - tolyl) sulfide , methyl ( 4 - tolyl) sulfide , methyl vinyl sul 5 - tetraoxide, 3, 6 -difluoro -1 ,4 , 2 ,5 -dioxadithiane -2 ,2 ,5 , 5 fide , methyl allyl sulfide ,methyl benzyl sulfide , ethyl phenyl tetraoxide, 3, 3 ,6 ,6 - tetramethyl- 1 ,4 , 2, 5 -dioxadithiane -2 ,2 ,5 , sulfide , ethyl ( 2 - tolyl ) sulfide , ethyl ( 3 - tolyl) sulfide , ethyl 5 - tetraoxide , 3, 3 ,6 ,6 - tetrafluoro - 1, 4, 2 ,5 -dioxadithiane - 2, 2 , 5 ( 4 - tolyl) sulfide , ethyl vinyl sulfide , ethyl allyl sulfide , ethyl 5 , 5 -tetraoxide , benzyl sulfide , 1 ,5 , 2, 4 -dioxadithian -6 -one - 2 , 2, 4 ,4 - tetraoxide, 3 -methyl - 1, 5 , phenyl propyl sulfide, phenyl isopropyl sulfide, phenyi n -bu tyl sulfide , phenyl isobutyl sulfide , phenyl tert- butyl sulfide , 2 , 4 -dioxadithian - 6 - one - 2 , 2 , 4 , 4 - tetraoxide, 3 , 3 - dimethyl- 1 , phenyl cyclopentyl sulfide , phenyl cyclohexyl sulfide , phe 5 ,2 , 4 -dioxadithian -6 -one - 2 ,2 ,4 , 4 - tetraoxide , 3 - fluoro - 1 ,5 , 2 , 10 nyl ( 2 -tolyl ) sulfide, phenyl ( 3 - tolyl ) sulfide , phenyl ( 4 - tolyl ) 4 -dioxadithian -6 -one -2 ,2 , 4 ,4 - tetraoxide, 3 ,3 -difluoro - 1 ,5 , 2 , sulfide, phenyl vinyl sulfide, phenyl allyl sulfide, phenyl 4 - dioxadithian - 6 -one - 2 , 2 ,4 , 4 - tetraoxide, benzyl sulfide , 1 ,5 , 2 ,4 - dioxadithiepane - 2 , 2 ,4 , 4 - tetraoxide, 3 -methyl - 1 , 5 , 2 , bis ( fluoromethyl) sulfide, bis ( difluoromethyl ) sulfide, bis ( tri 4 - dioxadithiepane - 2 , 2 ,4 , 4 - tetraoxide, 3 ,3 - dimethyl- 1 , 5 , 2 , 4 fluoromethyl) sulfide , di( 1 - fluoroethyl) sulfide, di( 2 - fluoro dioxadithiepane- 2 ,2 ,4 , 4 -tetraoxide , 3 - fluoro -1 92,5 , 2 , 4 - dioxa - 15 ethyl) sulfide , bis ( 2 , 2 , 2 - trifluoroethyl ) sulfide , bis ( perfluoro dithiepane - 2 ,2 ,4 , 4 -tetraoxide , 3, 3 -difluoro - 1, 5 ,2 ,4 ethyl) sulfide , bis ( 3 , 3 , 3 - trifluoro - n -propyl ) sulfide , bis ( 2 , 2 , 3 , dioxadithiepane - 2 ,2 ,4 , 4 -tetraoxide , 6 -methyl - 1, 5 ,2 , 4 3 , 3 -pentafluoro - n - propyl) sulfide , bis (perfluoro - n -propyl ) dioxadithiepane- 2 ,2 ,4 , 4 -tetraoxide , 6 ,7 -dimethyl - 1, 5 ,2 , 4 sulfide , di( 2 - fluoroisopropyl) sulfide , bis ( 2 , 2 , 2 , 2 ', 2 ', 2 ' dioxadithiepane - 2 , 2 , 4 , 4 - tetraoxide , 1 , 5 , 2 , 4 hexafluoroisopropyl) sulfide, bis (perfluoro - n -butyl ) sulfide, dioxadithiocane - 2 , 2 , 4 , 4 - tetraoxide, and 1 , 5 , 2 ,4 - 20 di( 2 - fluoro - tert -butyl ) sulfide , bis (perfluoro - tert - butyl) sul dioxadithionane - 2, 2 ,4 , 4 -tetraoxide , and the like . fide , di( 2 - fluorocyclohexyl) sulfide , di( 3 - fluorocyclohexyl) Preferred are compounds having a six -membered ring sulfide, di( 4 - fluorocyclohexyl ) sulfide , bis ( perfluorocyclo structure such as hexyl) sulfide , methyl ( fluoromethyl) sulfide , 1 , 5 , 2 , 4 -dioxadithiane - 2 , 2 , 4 , 4 - tetraoxide , 3 -methyl - 1 , 5 , 2 , 4 - methyl ( difluoromethyl) sulfide, methyl ( trifluoromethyl) dioxadithiane - 2 , 2 , 4 , 4 - tetraoxide , 3 , 3 - dimethyl - 1 , 5 , 2 ,4 - di- 25 sulfide , methyl ( 1 - fluoroethyl) sulfide , methyl ( 2 - fluoro oxadithiane - 2 , 2 , 4 , 4 - tetraoxide , 3 - fluoro - 1 , 5 , 2 , 4 - dioxadithi ethyl) sulfide , methyl ( 2 , 2 , 2 -trifluoroethyl ) sulfide , methyl ane - 2 , 2 , 4 , 4 - tetraoxide , 3 , 3 -difluoro - 1 , 5 , 2 , 4 - dioxadithiane - 2 , ( perfluoroethyl) sulfide , methyl ( 3 , 3 , 3 - trifluoro - n -propyl sul 2 , 4 ,4 - tetraoxide , 6 -methyl - 1 , 5 , 2 , 4 -dioxadithiane - 2 , 2 , 4 , 4 fide ) , methyl (2 , 2 , 3 , 3 , 3 -pentafluoro - n -propyl ) sulfide , tetraoxide, 6 ,6 - dimethyl- 1 , 5 , 2 , 4 - dioxadithiane - 2 , 2 , 4 , 4 methyl perfluoro -n -propyl sulfide , methyl (2 - fluoroisopro tettetraoxide , 6 - fluoro - 1 , 5 , 2 , 4 - dioxadithiane - 2 , 2 , 4 , 4 - 30 pyl) sulfide , methyl ( 2 , 2 , 2 , 2 ', 2 ', 2 '- hexafluoroisopropyl ) sul tetraoxide, 6 , 6 -difluoro - 1 , 5 , 2 , 4 - dioxadithiane - 2 , 2 , 4 , 4 - fide , methyl (perfluoro - n -butyl ) sulfide , methyl ( 2 - fluoro tetraoxide , 3 , 6 - dimethyl- 1 , 5 , 2 , 4 - dioxadithiane - 2 , 2 ,4 , 4 - tert - butyl) sulfide , methyl (perfluoro -tert - butyl sulfide , tetraoxide, 3 ,6 - difluoro - 1 , 5 , 2 , 4 - dioxadithiane - 2 , 2 , 4 , 4 - methyl ( 2 - fluorocyclohexyl) sulfide ,methyl ( 3 - fluorocyclo tetraoxide, 3 , 3 , 6 ,6 - tetramethyl- 1 , 5 , 2 , 4 -dioxadithiane - 2 , 2 ,4 , hexyl) sulfide , methyl ( 4 - fluorocyclohexyl) sulfide , methyl 4 -tetraoxide , 3 , 3 ,6 ,6 - tetrafluoro - 1 , 5 , 2 , 4 - dioxadithiane- 2 , 2 , 35 (perfluorocyclohexyl ) sulfide , 4 , 4 - tetraoxide, ethyl ( fluoromethyl) sulfide , ethyl ( difluoromethyl) sulfide, 1 ,4 , 2 , 5 - dioxadithiane - 2 , 2 , 5 , 5 -tetraoxide , 3 -methyl - 1 , 4 , 2 , 5 ethyl ( trifluoromethyl ) sulfide, ethyl ( 1 - fluoroethyl) sulfide , dioxadithiane - 2 , 2 , 5 , 5 - tetraoxide, 3 , 3 - dimethyl- 1 , 4 , 2 , 5 - di ethyl ( 2 - fluoroethyl) sulfide , ethyl ( 2 , 2 , 2 - trifluoroethyl) sul oxadithiane - 2 , 2 , 5 , 5 - tetraoxide, 3 - fluoro - 1 , 4 , 2 , 5 -dioxadithi fide , ethyl (perfluoroethyl ) sulfide, ethyl ( 3 , 3 , 3 - trifluoro - n ane - 2 , 2 , 5 , 5 - tetraoxide , 3 , 3 - difluoro - 1 , 4 , 2 , 5 - dioxadithiane - 2 , 40 propyl ) sulfide, ethyl ( 2 , 2 , 3 , 3 , 3 -pentafluoro - n - propyl ) sul 2 , 5 , 5 - tetraoxide , 3 ,6 - dimethyl- 1 , 4 , 2 , 5 -dioxadithiane - 2 , 2 , 5 , fide, ethyl (perfluoro -n -propyl ) sulfide , ethyl 5 -tetraoxide , 3 , 6 - difluoro - 1 ,4 , 2 , 5 - dioxadithiane - 2 , 2 ,5 , 5 - ( 2 - fluoroisopropyl) sulfide , ethyl ( 2 , 2 , 2 , 2 ', 2 ' , 2 ' -hexafluor tetraoxide , 3, 3 ,6 , 6 -tetramethyl - 1 , 4 , 2 , 5 -dioxadithiane - 2 , 2 ,5 , oisopropyl) sulfide , ethyl (perfluoro - n - butyl ) sulfide , ethyl 5 - tetraoxide , 3 , 3 ,6 ,6 - tetrafluoro - 1 , 4 , 2 , 5 -dioxadithiane - 2 , 2 , ( 2 - fluoro - tert- butyl) sulfide , ethyl (perfluoro - tert -butyl ) sul 5 , 5 -tetraoxide , 45 fide , ethyl ( 2 - fluorocyclohexyl) sulfide, ethyl ( 3 - fluorocyclo 1 , 5 , 2 ,4 -dioxadithian -6 - one - 2 , 2 , 4 , 4 - tetraoxide , 3 -methyl - 1 , 5 , hexyl) sulfide , ethyl ( 4 - fluorocyclohexyl )sulfide , ethyl ( per 2 , 4 -dioxadithian - 6 -one - 2 , 2 , 4 ,4 - tetraoxide , 3 , 3 - dimethyl- 1 , fluorocyclohexyl) sulfide , 5 , 2 , 4 -dioxadithian -6 -one - 2 , 2 , 4 , 4 - tetraoxide, 3 - fluoro - 1 , 5 , 2 , (2 ,2 , 2 - trifluoroethyl) ( fluoromethyl) sulfide, (2 ,2 ,2 -trifluoro 4 -dioxadithian - 6 -one -2 , 2 , 4 , 4 -tetraoxide , and 3 , 3 - difluoro - 1 , ethyl) (difluoromethyl ) sulfide, (2 ,2 , 2 - trifluoroethyl) ( trifluo 5 , 2 , 4 -dioxadithian - 6 -one - 2 , 2 , 4 , 4 - tetraoxide . 50 romethyl) sulfide, ( 2 , 2 , 2 - trifluoroethyl) ( 1 - fluoroethyl) sul < 1 - 2 - 6 . Sulfide Compounds > fide, ( 2 , 2 , 2 - trifluoroethyl) ( 2 - fluoroethyl) sulfide, ( 2 , 2 , 2 The sulfide compounds are not particularly limited in the trifluoroethyl) (perfluoroethyl ) sulfide , ( 2 ,2 ,2 - trifluoroethyl) kind thereof so long as they are compounds having a sulfide (3 , 3 ,3 - trifluoro -n -propyl ) sulfide , ( 2 ,2 ,2 - trifluoroethyl) (2 ,2 , structure in the molecule . Examples of the sulfide com 3, 3 ,3 -pentafluoro -n -propyl ) sulfide , (2 ,2 , 2 -trifluoroethyl ) pounds include 55 (perfluoro - n - propyl ) sulfide, ( 2 , 2 , 2 - trifluoroethyl) ( 2 dimethyl sulfide , diethyl sulfide , di- n -propyl sulfide , diiso - fluoroisopropyl) sulfide , (2 , 2 ,2 -trifluoroethyl ) ( 2 ,2 ,2 , 2' , 2 ', 2 ' propyl sulfide , di - n -butyl sulfide, diisobutyl sulfide , di- tert - hexafluoroisopropyl) sulfide, ( 2 , 2 , 2 - trifluoroethyl ) butyl sulfide , dicyclopentyl sulfide, dicyclohexyl sulfide, (perfluoro - n -butyl ) sulfide, ( 2 ,2 ,2 - trifluoroethyl )( 2 - fluoro ethylmethyl sulfide ,methyl propyl sulfide, methyl isopropyl tert -butyl ) sulfide, ( 2 , 2 , 2 - trifluoroethyl) ( perfluoro -tert - butyl) sulfide , methyl n -butyl sulfide , methyl isobutyl sulfide , 60 sulfide , ( 2 , 2 , 2 - trifluoroethyl) ( 2 - fluorocyclohexyl) sulfide , methyl tert- butyl sulfide, methyl cyclopentyl sulfide , methyl ( 2 , 2 , 2 - trifluoroethyl) ( 3 - fluorocyclohexyl) sulfide , ( 2 , 2 , 2 - trif cyclohexyl sulfide , ethyl propyl sulfide, ethyl isopropyl luoroethyl) ( 4 - fluorocyclohexyl) sulfide, ( 2 ,2 ,2 - trifluoro sulfide , ethyl n - butyl sulfide , ethyl isobutyl sulfide , ethyl ethyl) (perfluorocyclohexyl )sulfide , tert -butyl sulfide, ethyl cyclopentyl sulfide , ethyl cyclohexyl di( 2 - fluorophenyl ) sulfide , di ( 3 - fluorophenyl) sulfide , di ( 4 sulfide , 65 fluorophenyl )sulfide , bis ( 2 ,3 -difluorophenyl ) sulfide , bis (2 , diphenyl sulfide , di( 2 -tolyl ) sulfide, di( 3 - tolyl) sulfide , di( 4 - 4 -difluorophenyl ) sulfide, bis ( 3, 5 -difluorophenyl ) sulfide, bis tolyl) sulfide , divinyl sulfide , diallyl sulfide, dibenzyl sulfide , ( 2 ,4 , 6 - trifluorophenyl) sulfide, bis ( perfluorophenyl )sulfide , US 9 ,853 , 326 B2 97 98 di( 1 - fluorovinyl ) sulfide , di( 2 - fluorovinyl) sulfide , bis (per - ethyl methyl disulfide, methyl propyl disulfide, methyl iso fluorovinyl ) sulfide , bis [ ( 2 - fluorophenyl )methyl ] sulfide, bis propyl disulfide, methyl n - butyl disulfide, methyl isobutyl [ ( 3 - fluorophenyl) methyl sulfide, bis [ (4 - fluorophenyl ) disulfide , methyl tert -butyl disulfide, methyl cyclopentyl methyl] sulfide, bis [ (perfluorophenyl ) methyl ] sulfide , disulfide, methyl cyclohexyl disulfide , ethyl propyl disul methyl ( 2 - fluorophenyl) sulfide ,methyl (3 - fluorophenyl ) sul - 5 fide, ethyl isopropyl disulfide, ethyl n -butyl disulfide, ethyl fide, methyl ( 4 - fluorophenyl) sulfide , methyl ( 2 , 3 - difluoro isobutyl disulfide, ethyl tert - butyl disulfide , ethyl cyclopen phenyl) sulfide , methyl ( 2 , 4 - difluorophenyl) sulfide , methyl tyl disulfide, ethyl cyclohexyl disulfide , diphenyl disulfide , di( 2 - tolyl) disulfide , di( 3 - tolyl) disulfide , ( 3 ,5 -difluorophenyl ) sulfide, methyl (2 ,4 ,6 - trifluorophenyl) di( 4 - tolyl ) disulfide , divinyl disulfide, diallyl disulfide , sulfide , methyl ( perfluorophenyl) sulfide , methyl ( 1 - fluoro 10 dibenzyl disulfide, vinyl) sulfide, methyl ( 2 - fluorovinyl) sulfide , methyl perfluo methyl phenyl disulfide , methyl ( 2 - tolyl ) disulfide , methyl rovinyl sulfide, methyl[ ( 2 - fluorophenyl) methyl ] sulfide , ( 3 - tolyl) disulfide , methyl ( 4 - tolyl )disulfide , methyl vinyl methyl [ ( 3 - fluorophenyl) methyl ] sulfide , methyl [ (4 - fluoro disulfide, methyl allyl disulfide , methyl benzyl disulfide , phenyl) methyl ] sulfide, methyl [( perfluorophenyl ) methyl ] ethyl phenyl disulfide , ethyl ( 2 -tolyl ) disulfide, ethyl sulfide , ethyl ( 2 - fluorophenyl) sulfide , ethyl ( 3 - fluorophenyl) sulfide, 15 (ulfide 3 - tolyl ethyl) disulfide allví , disulfideethyl (4 - tolylethyl) benzyldisulfide disulfide, ethyl .vinyl dis ethyl (4 - fluorophenyl) sulfide , ethyl ( 2 ,3 -difluorophenyl ) sul phenyl propyl disulfide , phenyl isopropyl disulfide , phenyl fide, ethyl (2 ,4 -difluorophenyl ) sulfide , ethyl ( 3 ,5 -difluoro n -butyl disulfide, phenyl isobutyl disulfide, phenyl tert -butyl phenyl) sulfide , ethyl ( 2 , 4 ,6 - trifluorophenyl) sulfide , ethyl disulfide , phenyl cyclopentyl disulfide, phenyl cyclohexyl (perfluorophenyl ) sulfide , ethyl ( 1 - fluorovinyl) sulfide , ethyl 20 disulfide , phenyl ( 2 - tolyl) disulfide , phenyl ( 3 - tolyl) disulfide , ( 2- fluorovinyl) sulfide , ethyl (perfluorovinyl ) sulfide , ethyl p henyl ( 4 - tolyl) disulfide , phenyl vinyl disulfide, phenyl allyl [ ( 2 - fluorophenyl) ethyl] sulfide , ethyl [ ( 3 - fluorophenyl) disulfide , phenyl benzyl disulfide , methyl] sulfide , ethyl [ (4 - fluorophenyl) methyl ] sulfide, ethyl bis ( fluoromethyl) disulfide , bis (difluoromethyl ) disulfide , bis [ (perfluorophenyl )methyl ] sulfide , ( trifluoromethyl) disulfide, di( 1 - fluoroethyl) disulfide , di( 2 phenyl ( fluoromethyl) sulfide , phenyl (difluoromethyl ) sul- 25 fluoroethyl) disulfide , bis (2 , 2 , 2 - trifluoroethyl) disulfide , bis fide , phenyl ( trifluoromethyl) sulfide , phenyl ( 1 - fluoroethyl ) (perfluoroethyl ) disulfide , bis( 3 , 3 , 3 - trifluoro - n -propyl ) sulfide , phenyl (2 - fluoroethyl) sulfide , phenyl ( 2 ,2 ,2 - trifluo - disulfide, bis ( 2 , 2 ,3 , 3 ,3 -pentafluoro - n -propyl ) disulfide , bis roethyl) sulfide, phenyl (perfluoroethyl ) sulfide, phenyl ( 3 , 3 , ( perfluoro - n - propyl) disulfide , di ( 2 - fluoroisopropyl) 3 - trifluoro -n -propyl ) sulfide , phenyl ( 2 ,2 , 3 ,3 ,3 -pentafluoro disulfide , bis ( 2, 2, 2 ,2 ', 2 ', 2 '- hexafluoroisopropyl ) disulfide , bis n - propyl) sulfide , phenyl ( perfluoro - n - propyl) sulfide, phenyl 30 (perfluoro - n -butyl ) disulfide , di( 2 - fluoro - tert - butyl) ( 2 - fluoroisopropyl) sulfide, phenyl ( 2 , 2 , 2 , 2 ', 2 ', 2 '- hexafluor disulfide , bis (perfluoro - tert -butyl ) disulfide, di ( 2 oisopropyl) sulfide, phenyl ( perfluoro - n - butyl) sulfide , phe - fluorocyclohexyl) disulfide, di( 3 - fluorocyclohexyl) disulfide , nyl ( 2 - fluoro - tert -butyl ) sulfide, phenyl (perfluoro - tert -butyl ) di( 4 - fluorocyclohexyl) disulfide, bis (perfluorocyclohexyl ) sulfide, phenyl ( 2 - fluorocyclohexyl) sulfide , phenyl disulfide , ( 3 - fluorocyclohexyl) sulfide , phenyl (4 - fluorocyclohexyl) 35 methyl (fluoromethyl ) disulfide , methyl (difluoromethyl ) dis sulfide, phenyl (perfluorocyclohexyl ) sulfide, phenyl ulfide, methyl (trifluoromethyl )disulfide , methyl (1 - fluoro ( 2 - fluorophenyl) sulfide , phenyl ( 3 - fluorophenyl ) sulfide , ethyl) disulfide , methyl ( 2 - fluoroethyl) disulfide , methyl ( 2 , 2 , phenyl ( 4 - fluorophenyl) sulfide , phenyl ( 2 , 3 - difluorophenyl) 2 - trifluoroethyl) disulfide , methyl (perfluoroethyl ) disulfide , sulfide , phenyl (2 ,4 -difluorophenyl ) sulfide, phenyl ( 3 ,5 - dif - methyl ( 3 ,3 ,3 - trifluoro -n -propyl ) disulfide , methyl (2 ,2 ,3 , 3 , luorophenyl) sulfide, phenyl ( 2 ,4 ,6 -trifluorophenyl ) sulfide , 40 3 -pentafluoro -n -propyl ) disulfide, methyl (perfluoro -n - pro phenyl (perfluorophenyl ) sulfide, phenyl ( 1 - fluorovinyl ) sul - pyl )disulfide , methyl ( 2 - fluoroisopropyl) disulfide , methyl fide, phenyl ( 2 - fluorovinyl) sulfide, phenyl (perfluorovinyl ) ( 2 ,2 ,2 , 2' , 2 ', 2 '- hexafluoroisopropyl ) disulfide , methyl (per sulfide, phenyl ( 2 -fluorophenyl ) methyl sulfide, phenyl [ ( 3 fluoro -n -butyl ) disulfide, methyl (2 - fluoro - tert -butyl ) disul fluorophenyl) methyl ] sulfide , phenyl [ ( 4 - fluorophenyl) fide , methyl (perfluoro - tert -butyl ) disulfide , methyl ( 2 - fluo methyl] sulfide, phenyl [ (perfluorophenyl ) methyl ] sulfide, 45 rocyclohexyl) disulfide , methyl ( 3 - fluorocylohexyl ) ( 2 , 2 , 2 -trifluoroethyl ) ( 2 - fluorophenyl ) sulfide , ( 2 , 2 , 2 - trifluo - disulfide , methyl ( 4 - fluorocyclohexyl ) disulfide ,methyl ( per roethyl) ( 3 - fluorophenyl) sulfide , ( 2 , 2 , 2 - trifluoroethyl) ( 4 - fluorocyclohexyl) disulfide , fluorophenyl) sulfide, ( 2 ,2 ,2 - trifluoroethyl) ( 2 ,3 -difluorophe - ethyl ( fluoromethyl) disulfide , ethyl (difluoromethyl ) disul nyl) sulfide , ( 2 ,2 , 2 - trifluoroethyl) ( 2 ,4 -difluorophenyl ) fide, ethyl ( trifluoromethyl) disulfide , ethyl (1 - fluoroethyl) sulfide , ( 2 , 2 , 2 - trifluoroethyl) ( 3 , 5 - difluorophenyl) sulfide , 50 disulfide , ethyl ( 2 - fluoroethyl) disulfide, ethyl ( 2 , 2 , 2 - trifluo ( 2 , 2 , 2 - trifluoroethyl) ( 2 ,4 , 6 - trifluorophenyl) sulfide, ( 2 , 2 , 2 roethyl) disulfide, ethyl (perfluoroethyl ) disulfide , ethyl ( 3 , 3 , trifluoroethyl) ( perfluorophenyl) sulfide , (2 , 2 , 2 - trifluoro 3 - trifitrifluoro - n -propyl ) disulfide , ethyl ( 2 , 2 , 3 , 3 , 3 -pentafluoro ethyl) ( 1 - fluorovinyl) sulfide , ( 2 , 2 , 2 - trifluoroethyl) ( 2 - fluoro n -propyl ) disulfide, ethyl (perfluoro - n - propyl) disulfide , vinyl) sulfide , ( 2, 2 ,2 -trifluoroethyl ) ( perfluorovinyl ) sulfide , ethyl 2 - fluoroisopropyl disulfide , ethyl ( 2 , 2 ,2 , 2' , 2' , 2 ' ( 2 , 2 , 2 - trifluoroethyl) [ ( 2 - fluorophenyl) methyl ] sulfide , ( 2 , 2 , 55 hexafluoroisopropyl) disulfide , ethyl (perfluoro - n -butyl ) dis 2 -trifluoroethyl ) [ ( 3 - fluorophenyl) methyl ] sulfide , ( 2 , 2 , 2 - tri ulfide, ethyl ( 2 - fluoro - tert - butyl) disulfide , ethyl ( perfluoro fluoroethyl) [( 4 - fluorophenyl) methyl ] sulfide, and (2 , 2 ,2 - tri - tert -butyl ) disulfide , ethyl (2 - fluorocyclohexyl) disulfide , fluoroethyl) [ (perfluorophenyl ) methyl ] sulfide and the like . ethyl ( 3 - fluorocylohexyl) disulfide , ethyl ( 4 - fluorocyclo < 1 - 2 -7 . Disulfide Compounds > hexyl) disulfide, ethyl (perfluorocyclohexyl ) disulfide , The disulfide compounds are not particularly limited in 60 ( 2 , 2 , 2 - trifluoroethyl) ( fluoromethyl ) disulfide , ( 2 , 2 , 2 - trifluo the kind thereof so long as they are compounds having a roethyl) (difluoromethyl ) disulfide , (2 ,2 , 2 -trifluoroethyl ) (trif disulfide structure in the molecule . Examples of the disulfide l uoromethyl ) disulfide , ( 2 , 2 , 2 - trifluoroethyl ) ( 1 - fluoroethyl) compounds include disulfide, ( 2 , 2 , 2 -trifluoroethyl )( 2 - fluoroethyl) disulfide , ( 2 , 2 , dimethyl disulfide, diethyl disulfide , di- n -propyl disulfide , 2 - trifluoroethyl) ( perfluoroethyl) disulfide , (2 ,2 ,2 diisopropyl disulfide , di- n -butyl disulfide, diisobutyl disul- 65 trifluoroethyl) ( 3 , 3 , 3 - trifluoro - n - propyl) disulfide , ( 2 , 2 , 2 fide , di- tert - butyl disulfide , dicyclopentyl disulfide , dicyclo - trifluoroethyl) ( 2 , 2 , 3 , 3 , 3 - pentafluoro - n - propyl) disulfide , hexyl disulfide, ( 2 ,2 ,2 - trifluoroethyl) ( perfluoro -n -propyl ) disulfide, (2 ,2 , 2 US 9 ,853 , 326 B2 99 100 trifluoroethyl ) ( 2 - fluoroisopropyl) disulfide , ( 2 , 2 , 2 - trifluoro trifluorophenyl) disulfide , ( 2 , 2 , 2 - trifluoroethyl) ethyl) ( 2 , 2 , 2 , 2 ', 2 ', 2 '- hexafluoroisopropyl) disulfide , ( 2 , 2 , 2 - tri (perfluorophenyl ) disulfide , ( 2 , 2 , 2 - trifluoroethyl) ( 1 fluoroethyl) (perfluoro -n -butyl ) disulfide , (2 ,2 ,2 fluorovinyl )disulfide , ( 2 ,2 ,2 - trifluoroethyl) (2 - fluorovinyl) trifluoroethyl) ( 2 - fluoro - tert -butyl ) disulfide , ( 2 , 2 , 2 disulfide, ( 2 , 2 , 2 - trifluoroethyl) (perfluorovinyl ) disulfide , trifluoroethyl) ( perfluoro - tert- butyl ) disulfide , ( 2 ,2 , 2 - 5 ( 2 , 2 , 2 - trifluoroethyl) [ ( 2 - fluorophenyl)methyl ] disulfide , trifluoroethyl) ( 2 - fluorocyclohexyl) disulfide , ( 2 , 2 , 2 ( 2 , 2 , 2 - trifluoroethyl) [ ( 3 - fluorophenyl) methyl ] disulfide , trifluoroethyl ) ( 3 - fluorocyclohexyl) disulfide , (2 , 2 ,2 ( 2 , 2 , 2 - trifluoroethyl) [ ( 4 - fluorophenyl) methyl ] disulfide , and trifluoroethyl) ( 4 - fluorocyclohexyl) disulfide , ( 2 , 2 , 2 - ( 2 , 2 , 2 - trifluoroethyl ) [ (perfluorophenyl ) methyl ] disulfide trifluoroethyl) (perfluorocyclohexyl ) disulfide, and the like . di( 2 - fluorophenyl) disulfide, di( 3 - fluorophenyl) disulfide, 10 < 1 - 2 - 8 . Acid Anhydrides > di( 4 - fluorophenyl) disulfide , bis ( 2 , 3 -difluorophenyl ) disul The acid anhydrides are not limited in the kind thereof. fide, bis ( 2 , 4 -difluorophenyl ) disulfide , bis (3 ,5 -difluorophe The acid anhydrides may be compounds each having two or nyl) disulfide , bis ( 2 ,4 , 6 -trifluorophenyl ) disulfide , bis (per - more acid anhydride structures per molecule . Examples of fluorophenyl) disulfide, di( 1 - fluorovinyl) disulfide, di( 2 the acid anhydrides usable in invention 3 include the anhy fluorovinyl) disulfide , bis( perfluorovinyl )disulfide , bis [ ( 2 - 15 drides of carboxylic acids , the anhydrides of sulfonic acids , fluorophenyl) methyl ] disulfide , bis[ ( 3 - fluorophenyl) methyl ] and the anhydrides of carboxylic acids and sulfonic acids . disulfide , bis [ (4 - fluorophenyl) methyl ]disulfide , bis Examples of the carboxylic acid anhydrides include [ (perfluorophenyl )methyl ] disulfide , acetic anhydride , propionic anhydride , butyric anhydride , methyl (2 - fluorophenyl) disulfide , methyl ( 3 - fluorophenyl) crotonic anhydride, trifluoroacetic anhydride, pentafluoro disulfide , methyl (4 - fluorophenyl ) disulfide , methyl ( 2 , 3 - di- 20 propionic anhydride, succinic anhydride, glutaric anhydride , fluorophenyl) disulfide , methyl ( 2 , 4 -difluorophenyl ) disul- maleic anhydride , citraconic anhydride , glutaconic anhy fide , methyl ( 3 , 5 - difluorophenyl) disulfide , methyl ( 2 ,4 ,6 - dride, itaconic anhydride, diglycolic anhydride , cyclo trifluorophenyl) disulfide , methyl (perfluorophenyl ) hexanedicarboxylic anhydride , cyclopentanetetracarboxylic disulfide , methyl ( 1 - fluorovinyl) disulfide, methyl ( 2 - fluoro - dianhydride , 4 - cyclohexene - 1 , 2 - dicarboxylic anhydride, vinyl ) disulfide , methyl (perfluorovinyl ) disulfide , methyl 25 3 , 4 , 5 , 6 - tetrahydrophthalic anhydride , 5 - norbornene - 2 , 3 - di [ ( 2 - fluorophenyl) methyl ] disulfide, methyl [ ( 3 - fluorophenyl ) carboxylic anhydride , phenylsuccinic anhydride , 2 -phenyl methyl] disulfide , methyl [ ( 4 - fluorophenyl) methyl ]disulfide , glutaric anhydride , phthalic anhydride , pyromellitic anhy methyl [ (perfluorophenyl ) methyl ] disulfide , dride , fluorosuccinic anhydride , and tetrafluorosuccinic ethyl ( 2 - fluorophenyl) disulfide , ethyl ( 3 - fluorophenyl) dis anhydride , and the like . ulfide , ethyl ( 4 - fluorophenyl) disulfide , ethyl ( 2 , 3 -difluoro - 30 Preferred of these are phenyl) disulfide, ethyl ( 2 , 4 - difluorophenyl) disulfide, ethyl succinic anhydride , glutaric anhydride , maleic anhydride , ( 3, 5 - difluorophenyl) disulfide, ethyl (2 ,4 , 6 - trifluorophenyl) citraconic anhydride , itaconic anhydride, diglycolic anhy disulfide , ethyl ( perfluorophenyl ) disulfide , ethyl ( 1 - fluoro dride , cyclohexanedicarboxylic anhydride, fluorosuccinic vinyl) disulfide, ethyl ( 2 - fluorovinyl) disulfide, ethyl (per anhydride , and tetrafluorosuccinic anhydride. fluorovinyl) disulfide , ethyl [ ( 2 - fluorophenyl) ethyl] disulfide , 35 Examples of the sulfonic acid anhydrides include meth ethyl [ ( 3 - fluorophenyl )methyl ] disulfide , ethyl [ ( 4 - fluoro anesulfonic anhydride, ethanesulfonic anhydride , propane phenyl) methyl ]disulfide , ethyl [ (perfluorophenyl ) methyl ] d sulfonic anhydride , butanesulfonic anhydride, pentanesulfo isulfide, nic anhydride , hexanesulfonic anhydride , vinylsulfonic phenyl ( fluoromethyl) disulfide , phenyl (difluoromethyl ) dis anhydride , benzenesulfonic anhydride , trifluoromethanesul ulfide , phenyl ( trifluoromethyl ) disulfide , phenyl ( 1 - fluoro - 40 fonic anhydride , 2 , 2 , 2 - trifluoroethanesulfonic anhydride , ethyl) disulfide , phenyl ( 2 - fluoroethyl) disulfide , phenyl ( 2 , 2 , pentafluoroethanesulfonic anhydride, 1 , 2 - ethanedisulfonic 2 - trifluoroethyl ) disulfide , phenyl ( perfluoroethyl ) disulfide , anhydride, 1 , 3 -propanedisulfonic anhydride , 1 , 4 -butanedis phenyl (3 , 3, 3 - trifluoro - n -propyl ) disulfide , phenyl ( 2 ,2 ,3 ,3 , 3 - ulfonic anhydride, 1, 2 -benzenedisulfonic anhydride, tetra pentafluoro - n - propyl) disulfide, phenyl (perfluoro - n -propyl ) fluoro - 1 , 2 -ethanedisulfonic anhydride , hexafluoro - 1 , 3 - pro disulfide , phenyl ( 2 - fluoroisopropyl ) disulfide , phenyl (2 , 2 , 45 panedisulfonic anhydride , octafluoro - 1 , 4 -butanedisulfonic 2 , 2 ', 2 ', 2 ' - hexafluoroisopropyl ) disulfide, phenyl (perfluoro anhydride, 3 - fluoro - 1 , 2 -benzenedisulfonic anhydride , n -butyl ) disulfide , phenyl ( 2 - fluoro - tert- butyl )disulfide , 4 -fluoro - 1 , 2 - benzenedisulfonic anhydride , and 3 ,4 , 5 ,6 - tetra phenyl (perfluoro -tert -butyl ) disulfide, phenyl ( 2 - fluorocy - fluoro - 1 ,2 -benzenedisulfonic anhydride, and the like . clohexyl )disulfide , phenyl (3 - fluorocylohexyl) disulfide , Preferred of these are phenyl ( 4 - fluorocyclohexyl) disulfide, phenyl ( perfluorocy - 50 methanesulfonic anhydride, ethanesulfonic anhydride, pro clohexyl) disulfide , phenyl ( 2 - fluorophenyl) disulfide , phe - panesulfonic anhydride, butanesulfonic anhydride , vinylsul nyl ( 3 - fluorophenyl) disulfide , phenyl ( 4 -fluorophenyl ) disul- fonic anhydride , benzenesulfonic anhydride , trifluorometh fide, phenyl ( 2, 3 - difluorophenyl) disulfide, phenyl (2 , 4 anesulfonic anhydride, 2 , 2 ,2 - trifluoroethanesulfonic difluorophenyl) disulfide , phenyl ( 3 , 5 -difluorophenyl ) anhydride, pentafluoroethanesulfonic anhydride, 1 , 2 - eth disulfide, phenyl (2 , 4 ,6 - trifluorophenyl) disulfide , phenyl 55 anedisulfonic anhydride , 1 , 3 -propanedisulfonic anhydride, ( perfluorophenyl) disulfide, phenyl ( 1 - fluorovinyl) disulfide , 1 , 2 -benzenedisulfonic anhydride, and the like . phenyl ( 2 -fluorovinyl ) disulfide , phenyl perfluorovinyl dis - Examples of the anhydrides of carboxylic acids and ulfide, phenyl [( 2 - fluorophenyl )methyl ] disulfide , phenyl sulfonic acids include [ ( 3 - fluorophenyl) methyl ] disulfide, phenyl [ ( 4 - fluorophenyl) acetic methanesulfonic anhydride, acetic ethanesulfonic methyl] disulfide , phenyl [ (perfluorophenyl ) methyl ] disul- 60 anhydride, acetic propanesulfonic anhydride, propionic fide , methanesulfonic anhydride , propionic ethanesulfonic anhy ( 2 , 2 , 2 - trifluoroethyl) ( 2 - fluorophenyl ) disulfide , ( 2 , 2 , 2 - trif - dride , propionic propanesulfonic anhydride , trifluoroacetic luoroethyl) ( 3 - fluorophenyl) disulfide , ( 2 , 2 , 2 -trifluoroethyl ) methanesulfonic anhydride , trifluoroacetic ethanesulfonic ( 4 - fluorophenyl) disulfide, ( 2 , 2 , 2 - trifluoroethyl) ( 2 , 3 - difluo anhydride , trifluoroacetic propanesulfonic anhydride , acetic rophenyl) disulfide , ( 2 , 2 , 2 - trifluoroethyl) ( 2 , 4 - 65 trifluoromethanesulfonic anhydride , acetic 2 , 2 , 2 -trifluo difluorophenyl )disulfide , ( 2 , 2 , 2 - trifluoroethyl) ( 3 , 5 - roethanesulfonic anhydride , acetic pentafluoroethanesulfo difluorophenyl) disulfide , ( 2 , 2 , 2 - trifluoroethyl) ( 2 , 4 , 6 - nic anhydride, trifluoroacetic trifluoromethanesulfonic US 9 ,853 , 326 B2 101 102 anhydride, trifluoroacetic 2 , 2 , 2 - trifluoroethanesulfonic rolactone, a , a - diethyl- y - butyrolactone , a - ethyl- a -methyl - y anhydride , trifluoroacetic pentafluoroethanesulfonic anhy - butyrolactone , A -methyl - a - phenyl- y -butyrolactone , aa dride , 3 -sulfopropionic anhydride, 2 -methyl - 3 -sulfopropi diphenyl- y -butyrolactone , d , a - ditolyl - y -butyrolactone , a , a onic anhydride , 2 , 2 -dimethyl - 3 - sulfopropionic anhydride, bis (dimethylphenyl ) - y -butyrolactone , ana - dinaphthyl- y 2 - ethyl- 3 - sulfopropionic anhydride , 2 , 2 - diethyl- 3 - sulfopro - 5 butyrolactone , a , a - divinyl- y -butyrolactone , a , a - diallyl- y pionic anhydride, 2 - fluoro - 3 - sulfopropionic anhydride, 2 , 2 - butyrolactone , C , a - dibenzyl- y - butyrolactone, ana difluoro - 3 -sulfopropionic anhydride, 2 ,2 , 3 ,3 ,- tetrafluoro - 3 diphenethyl -y -butyrolactone , and a , a -difluoro - y sulfopropionic anhydride, 2 - sulfobenzoic anhydride, butyrolactone , and the like ; 3 - fluoro - 2 -sulfobenzoic anhydride , 4 - fluoro -2 -sulfobenzoic y -valerolactone derivatives such as a -methyl - y -valerolac anhydride , 5 - fluoro -2 -sulfobenzoic anhydride, 6 - fluoro - 2 - 10 tone, a - ethyl- y -valerolactone , A -propyl - y -valerolactone , sulfobenzoic anhydride , 3 , 6 - difluoro - 2 - sulfobenzoic anhy - a - vinyl- y -valerolactone , a - allyl- y - valerolactone , a - phenyl dride, 3 , 4 , 5 ,6 - tetrafluoro - 2 - sulfobenzoic anhydride, 3 -trif - y - valerolactone , a - tolyl- y - valerolactone, a - naphthyl - y - vale luoromethyl- 2 - sulfobenzoic anhydride , 4 - trifluoromethyl- 2 - rolactone, a - fluoro - y- valerolactone, & , - dimethyl -y -valero sulfobenzoic anhydride, 5 - trifluoromethyl- 2 -sulfobenzoic lactone , , a -diethyl - y - valerolactone , C -ethyl - a -methyl - y anhydride, and 6 - trifluoromethyl- 2 -sulfobenzoic anhydride , 15 valerolactone , a -methyl - a - phenyl - y - valerolactone , a , & and the like . diphenyl - y - valerolactone , a , a - ditolyl - y - valerolactone , a , a Preferred of these are bis (dimethylphenyl ) - y - valerolactone , ana - dinaphthyl- y acetic methanesulfonic anhydride , acetic ethanesulfonic valerolactone , aga - divinyl- y -valerolactone , a , a -diallyl - y anhydride , acetic propanesulfonic anhydride , propionic valerolactone , a , a - dibenzyl- y - valerolactone , aa methanesulfonic anhydride, propionic ethanesulfonic anhy - 20 diphenethyl - y - valerolactone , and a , a - difluoro - y dride , propionic propanesulfonic anhydride, trifluoroacetic valerolactone, and the like ; methanesulfonic anhydride, trifluoroacetic ethanesulfonic 8 -valerolactone derivatives such as A -methyl - d -valerolac anhydride, trifluoroacetic propanesulfonic anhydride , acetic tone , a -ethyl - 8 -valerolactone , C -propyl - 8 - valerolactone , trifluoromethanesulfonic anhydride , acetic 2 , 2 , 2 -trifluo - a - vinyl- 8 - valerolactone , a - allyl- 6 - valerolactone , a - phenyl roethanesulfonic anhydride , acetic pentafluoroethanesulfo - 25 d - valerolactone , a -tolyl - 8 - valerolactone , a -naphthyl - 6 nic anhydride , trifluoroacetic trifluoromethanesulfonic valerolactone, - fluoro - d - valerolactone, C , a -dimethyl - d anhydride , trifluoroacetic 2 , 2 , 2 - trifluoroethanesulfonic valerolactone , ana -diethyl - 6 - valerolactone, a - ethyl- a anhydride, trifluoroacetic pentafluoroethanesulfonic anhy - methyl - d - valerolactone, a -methyl - a - phenyl - 8 dride , 2 - sulfobenzoic anhydride , 3 -fluoro -2 - sulfobenzoic valerolactone , a ,a -diphenyl -d - valerolactone , a ,a -ditolyl - 8 anhydride , 4 - fluoro - 2 - sulfobenzoic anhydride , 5 - fluoro - 2 - 30 valerolactone , ana - bis( dimethylphenyl) - 8 - valerolactone , sulfobenzoic anhydride , 6 - fluoro - 2 - sulfobenzoic anhydride, ana -dinaphthyl - d - valerolactone , ana -divinyl - d - valerolac and the like . tone , a ,a - diallyl- d - valerolactone, ana -dibenzyl - d -valero < 1 - 2 - 9 . Lactone Compounds Having Substituent in a -Posi lactone, a , a - diphenethyl- d - valerolactone , and a , a - difluoro tion > d - valerolactone ; The lactone compounds having a substituent in the a -po - 35 y -caprolactone derivatives such as a -methyl - y -caprolactone , sition are not particularly limited. Examples thereof include Q - ethyl- y - caprolactone, A -propyl -y -caprolactone , a -vinyl -y B -propiolactone derivatives such as a -methyl - B -propiolac lac caprolactone , a - allyl- y - caprolactone , a - phenyl - y -caprolac tone , - ethyl- B - propiolactone, C -propyl - B - propiolactone , tone , a -tolyl - y -caprolactone , a - naphthyl- y - caprolactone , a - vinyl- ß -propiolactone , a -allyl - B - propiolactone , a - phe a - fluoro - y - caprolactone, a , a -dimethyl - y - caprolactone , a , a nyl- B -propiolactone , a -tolyl - B -propiolactone , a -naphthyl - 40 diethyl- y -caprolactone , a -ethyl - a -methyl - y- caprolactone , B -propiolactone , a - fluoro - B -propiolactone , a , a -dimethyl - B a -methyl - a -phenyl - y -caprolactone , Ana -diphenyl - y -capro propiolactone, ana -diethyl - B -propiolactone , a -ethyl - a - lactone , a , a - ditolyl- y -caprolactone , a , a -bis ( dimethylphe methyl- B - propiolactone , nyl ) - y - caprolactone , a , a - dinaphthyl- y - caprolactone , d , a - di propiolactone , aga - diphenyl- B -propiolactone , a , a - ditolyl- vinyl- y - caprolactone , C , a -diallyl - y - caprolactone , aa B - propiolactone, a , a - bis ( dimethylphenyl) - B - propiolactone, 45 dibenzyl- y - caprolactone , a , a - diphenethyl- y - caprolactone , aga -dinaphthyl - B -propiolactone , ana -divinyl - ß -propiolac and a ,a -difluoro -y -caprolactone , and the like ; tone, a , a - diallyl- B -propiolactone , a , a -dibenzyl - B -propio d -caprolactone derivatives such as a -methyl - d -caprolac lactone, ana - diphenethyl - B - propiolactone, and aga - dif tone, a - ethyl - d - caprolactone, a - propyl - d - caprolactone , luoro - B -propiolactone , and the like ; a - vinyl - d - caprolactone, a - allyl- d -caprolactone , a -phenyl B -butyrolactone derivatives such as a -methyl - B -butyrolac - 50 d -caprolactone , a - tolyl- 8 - caprolactone , a -naphthyl - 8 tone , a -ethyl - B -butyrolactone , C -propyl - ß -butyrolactone , caprolactone, a -fluoro -d - caprolactone , ana -dimethyl - d A - vinyl- ß -butyrolactone , a -allyl - ß -butyrolactone , A - phe caprolactone , a , a - diethyl- d - caprolactone , a - ethyl- a nyl- ß -butyrolactone , a - tolyl- B -butyrolactone , a -naphthyl methyl - d - caprolactone, a -methyl - a - phenyl- d - caprolactone , B -butyrolactone , a - fluoro - ß -butyrolactone , a , a -dimethyl - ß aga - diphenyl- d -caprolactone , aga - ditolyl- d - caprolactone , butyrolactone , ana - diethyl- ß -butyrolactone , - ethyl- a - 55 a , a - bis (dimethylphenyl ) - d - caprolactone , ana -dinaphthyl - d methyl- ß - butyrolactone , a -methyl - a -phenyl - B caprolactone , a a -divinyl -d - caprolactone , a , a -diallyl - 8 butyrolactone , ca -diphenyl - B -butyrolactone , da - ditolyl - caprolactone , C , a - dibenzyl - d - caprolactone , ana - diphen B -butyrolactone , a , a -bis ( dimethylphenyl) - B -butyrolactone , ethyl- d - caprolactone , and a , -difluoro - d -caprolactone , and a , a - dinaphthyl- B -butyrolactone , ana -divinyl - B -butyrolac - the like ; and tone , a , a - diallyl- ß -butyrolactone , a , a -dibenzyl - B -butyro - 60 E -caprolactone derivatives such as a -methyl - e -caprolactone , lactone, ana - diphenethyl - ß - butyrolactone, and ana - dif a -ethyl - e -caprolactone , a -propyl - e - caprolactone , a - vinyl- e luoro - B - butyrolactone, and the like ; caprolactone , a - allyl- e -caprolactone , a -phenyl - e - caprolac y -butyrolactone derivatives such as a -methyl - y -butyrolac tone, a -tolyl - e - caprolactone, a - naphthyl - e - caprolactone, tone , a - ethyl- y -butyrolactone , a - propyl- y -butyrolactone , a - fluoro - e - caprolactone , a , a - dimethyl- e - caprolactone , a , a a -vinyl - y -butyrolactone , a - allyl- y - butyrolactone , a -phenyl - 65 diethyl- e - caprolactone, a - ethyl- a -methyl - e - caprolactone , y - butyrolactone , a - tolyl- y -butyrolactone , a -naphthyl - y - bu - a -methyl - a -phenyl - e - caprolactone , a , a - diphenyl- e - capro tyrolactone, a - fluoro -y -butyrolactone , a ,a -dimethyl - y- buty - lactone , a ,a - ditolyl- e -caprolactone , a , a -bis ( dimethylphe US 9 ,853 , 326 B2 103 104 nyl) - e -caprolactone , ana -dinaphthyl - e -caprolactone , a ,a - diol dipropanesulfonate , 2 -butyne - 1 , 4 -diol divinyl - e - caprolactone , a , a -diallyl - e -caprolactone , aa dicyclohexanesulfonate, and 2 -butyne - 1, 4 -diol dibenzene dibenzyl- e -caprolactone , ana -diphenethyl - c - caprolactone , sulfonate etc . and a , a -difluoro - e - caprolactone , and the like . < 1 - 2 - 11 . Content, Technical Range , etc . > Preferred of these are One of such compounds enumerated above as “ compound a - methyl- substituted lactones such as a -methyl - y -butyro - A of invention 3 ” , i . e . , at least one compound selected from lactone, a -methyl - y -valerolactone , A -methyl - 8 -valerolac the group consisting of compounds represented by general tone , and a -methyl - d -caprolactone etc .; a -phenyl - substi formula ( 1 ), nitrile compounds, isocyanate compounds, tuted lactones such as a - phenyl- y -butyrolactone , a -phenyl - phosphazene compounds, disulfonic acid ester compounds , y -valerolactone , a -phenyl - 8 - valerolactone , and a -phenyl - d - " sulfide compounds, disulfide compounds , acid anhydrides, caprolactone ; a , a -dimethyl - substituted lactones such as balactone compounds having a substituent in the a -position , aga - dimethyl- y -butyrolactone , ana -dimethyl - y -valerolac and compounds having a carbon - carbon triple bond , may be tone , a , a -dimethyl - d - valerolactone , a , a - dimethyl- y - capro - used alone . Alternatively , any desired combination of two or lactone, and a , a - dimethyl- d - caprolactone etc .; and a , a - 15 . more of these compounds in any desired proportion may be diphenyl- substituted lactones such as a , a - diphenyl- y used . Furthermore , with respect to each of those classes of butyrolactone, aga -diphenyl - y -valerolactone , d , a - diphenyl - “ compound A of invention 3 ” , one of the compounds falling d -valerolactone , ana - diphenyl -y -caprolactone , and ana under the class may be used alone or any desired combina diphenyl- d - caprolactone ; and the like. tion of two or more thereof in any desired proportion may be More preferred of these are 20 used . a -methyl - y -butyrolactone , a -phenyl - y -butyrolactone , aa The content of the “ compound A of invention 3 ” in dimethyl - y -butyrolactone , ana - diphenyl- y -butyrolactone , nonaqueous electrolyte 3 is not particularly limited . How and the like . ever, the total content thereof is generally 0 .001 % by mass < 1 - 2 - 10 . Compounds Having Carbon - Carbon Triple Bond > or higher , more preferably 0 .01 % by mass or higher , even The compounds having a carbon -carbon triple bond are 25 more preferably 0 . 1 % by mass or higher, based on the whole not particularly limited in the kind thereof so long as they are nonaqueous electrolyte . The upper limit of the total content compounds having a carbon -carbon triple bond in the mol- thereof is 50 % by mass or lower, more preferably 25 % by ecule . mass or lower, even more preferably 10 % by mass or lower , Examples of the compounds having a carbon -carbon especially preferably 5 % by mass or lower . When the triple bond include 30 concentration of “ compound A of invention 3 ” is too low , carbonate compounds such as 2 -propynyl methyl carbonate , there are cases where the effect of improving continuous 2 -propynyl ethyl carbonate , 2 -propynyl propyl carbonate , charge characteristics is difficult to obtain . On the other 2 - propynyl butyl carbonate , 2 - propynyl cyclohexyl carbon - hand , too high concentrations thereof may result in a ate , 2 -propynyl phenyl carbonate , bis - 2 -propynyl carbonate , decrease in charge / discharge efficiency . 2 -butynyl methyl carbonate , 2 -butynyl ethyl carbonate , 35 < 1 -3 . Nonaqueous Solvent > 2 -butynyl propyl carbonate , 2 -butynyl butyl carbonate , The nonaqueous solvent contained in nonaqueous elec 2 - butynyl cyclohexyl carbonate , 2 - butynyl phenyl carbon - trolyte 3 of the invention is not particularly limited in the use ate , bis -2 -butynyl carbonate , 3 -butynyl methyl carbonate , and kind thereof so log as the solvent is a nonaqueous 3 - butynyl ethyl carbonate , 2 - pentynyl methyl carbonate , solvent which does not adversely influence battery charac 1 -methyl - 2 - butynyl methyl carbonate , 2 - butyne - 1 , 4 -diol 40 teristics after battery fabrication . Examples thereof include dimethyl carbonate , 2 -butyne - 1 , 4 -diol diethyl carbonate , the organic solvents enumerated above . However, it is 2 -butyne -1 , 4 -diol dipropyl carbonate , 2- butyne- 1 ,4 -diol preferred to employ one or more of the following nonaque dicyclohexyl carbonate , and 2 -butyne - 1 ,4 - diol diphenyl car ous solvents for use in nonaqueous electrolytes . bonate , and the like ; Examples of the usable nonaqueous solvents include carboxylic acid ester compounds such as 2 -propynyl acetate , 45 acyclic or cyclic carbonates, acyclic or cyclic carboxylic 2 -propynyl propionate , 2- propynyl butyrate, 2 -propynyl acid esters, acyclic or cyclic ethers , and sulfur- containing cyclohexanecarboxylate , 2 -propynyl benzoate , 2 -butynyl organic solvents , and the like . acetate , 2 - butynyl propionate , 2 -butynyl butyrate , 2 -butynyl The acyclic carbonates also are not limited in the kind cyclohexanecarboxylate , 2 -butynyl benzoate , 3 -butynyl thereof . However, dialkyl carbonates are preferred . The acetate , 3 - butynyl propionate , 3 -butynyl butyrate , 3 -butynyl 50 number of carbon atoms of each constituent alkyl group is cyclohexanecarboxylate , 3 -butynyl benzoate , 2 -pentynyl preferably 1 -5 , especially preferably 1 - 4 . Examples thereof acetate , 1 -methyl - 2 -butynyl acetate , 2 - butyne - 1 , 4 -diol diac include etate , 2 - butyne - 1 , 4 - diol dipropionate , 2 - butyne - 1 , 4 - diol dimethyl carbonate , ethyl methyl carbonate , diethyl carbon dicyclohexanecarboxylate , and 2 -butyne - 1 , 4 - diol dibenzo ate , methyl n - propyl carbonate , ethyl n - propyl carbonate , ate etc . ; and 55 and di- n -propyl carbonate , and the like . sulfonic acid ester compounds such as 2 - propynyl methane Of these , dimethyl carbonate , ethyl methyl carbonate , or sulfonate , 2 -propynyl ethanesulfonate , 2 -propynyl propane diethyl carbonate is preferred from the standpoint of indus sulfonate , 2 - propynyl cyclohexanesulfonate , 2 - propynyl trial availability and because these compounds are satisfac benzenesulfonate , 2 -butynyl methanesulfonate , 2 -butynyl tory in various properties in a nonaqueous -electrolyte sec ethanesulfonate , 2 -butynyl propanesulfonate , 2 -butynyl 60 ondary battery . cyclohexanesulfonate , 2 - butynyl benzenesulfonate , 3 -buty . The cyclic carbonates are not limited in the kind thereof. nylmethanesulfonate , 3 -butynyl ethanesulfonate , 3 -butynyl However, the number of carbon atoms of the alkylene group propanesulfonate , 3 -butynyl cyclohexanesulfonate , 3 -buty - constituting each cyclic carbonate is preferably 2 -6 , espe nyl benzenesulfonate , 2 -pentynyl methanesulfonate , cially preferably 2 - 4 . Examples of the cyclic carbonates 1 - methyl- 2 - butynyl methanesulfonate , 2 - propynyl trifluo - 65 include ethylene carbonate , propylene carbonate , and buty romethanesulfonate , 2 -propynyl pentafluoroethanesul- lene carbonate ( 2 - ethylethylene carbonate or cis - and trans fonate , 2 -butyne - 1, 4 -diol dimethanesulfonate , 2 -butyne -1 , 4 - 2 ,3 -dimethylethylene carbonates) , and the like . US 9 ,853 , 326 B2 105 106 Of these , ethylene carbonate or propylene carbonate is by volume of the cyclic carbonate to the sum of the cyclic preferred because these compounds are satisfactory in vari carbonate and the acyclic carbonate is preferably 5 % by ous properties in a nonaqueous- electrolyte secondary bat volume or higher ,more preferably 10 % by volume or higher, tery . especially preferably 15 % by volume or higher , and is The acyclic carboxylic acid esters also are not limited in 5 generally 50 % by volume or lower , preferably 35 % by the kind thereof. Examples thereof include volumeor lower, more preferably 30 % or lower. Use of such methyl acetate, ethyl acetate , n - propyl acetate , isopropyl combination of nonaqueous solvents is preferred because the acetate , n -butyl acetate , isobutyl acetate , tert- butyl acetate , battery fabricated with this combination has an improved methyl propionate , ethyl propionate , n - propyl propionate , balance between cycle characteristics and high - temperature isopropyl propionate , n - butyl propionate , isobutyl propi- 10 storability ( in particular, residual capacity and high - load onate , and tert -butyl propionate , and the like . discharge capacity after high - temperature storage ) . Of these , ethyl acetate , methyl propionate , or ethyl pro - Examples of the preferred combination including at least pionate is preferred from the standpoint of industrial avail - one cyclic carbonate and at least one acyclic carbonate ability and because these compounds are satisfactory in include : ethylene carbonate and dimethyl carbonate ; ethyl various properties in a nonaqueous -electrolyte secondary 15 ene carbonate and diethyl carbonate ; ethylene carbonate and battery . ethyl methyl carbonate ; ethylene carbonate , dimethyl car The cyclic carboxylic acid esters also are not limited in bonate , and diethyl carbonate ; ethylene carbonate , dimethyl the kind thereof . Examples of such esters in ordinary use carbonate , and ethyl methyl carbonate ; ethylene carbonate , include y -butyrolactone , y - valerolactone , and 8 - valerolac - diethyl carbonate , and ethyl methyl carbonate ; and ethylene tone , and the like . 20 carbonate , dimethyl carbonate , diethyl carbonate , and ethyl Of these, y -butyrolactone is preferred from the standpoint methyl carbonate , and the like . of industrial availability and because this compound is Combinations obtained by further adding propylene car satisfactory in various properties in a nonaqueous - electro bonate to those combinations including ethylene carbonate lyte secondary battery . and one or more acyclic carbonates are also included in The acyclic ethers also are not limited in the kind thereof. 25 preferred combinations. In the case where propylene car Examples thereof include bonate is contained , the volume ratio of the ethylene car dimethoxymethane, dimethoxyethane , diethoxymethane , bonate to the propylene carbonate is preferably from 99 : 1 to diethoxyethane , ethoxymethoxymethane , and 40 :60 , especially preferably from 95 : 5 to 50 :50 . It is also ethoxymethoxyethane , and the like . preferred to regulate the proportion of the propylene car Of these, dimethoxyethane or diethoxyethane is preferred 30 bonate to the whole nonaqueous solvent to a value which is from the standpoint of industrial availability and because 0 . 1 % by volume or higher , preferably 1 % by volume or these compounds are satisfactory in various properties in a higher, more preferably 2 % by volume or higher , and is nonaqueous- electrolyte secondary battery. 8generally 10 % by volume or lower , preferably 8 % by The cyclic ethers also are not limited in the kind thereof. volume or lower, more preferably 5 % by volume or lower . Examples thereof include 35 This is because this regulation brings about excellent dis tetrahydrofuran , 2 -methyltetrahydrofuran , and tetrahydro - charge load characteristics while maintaining the properties pyran , and the like . of the combination of ethylene carbonate and one or more Furthermore, the sulfur- containing organic solvents also acyclic carbonates. are not particularly limited in the kind thereof. Examples More preferred of these are combinations including an thereof include 40 asymmetric acyclic carbonate . In particular , combinations ethylene sulfite , 1 , 3 - propanesultone, 1 , 4 -butanesultone , including ethylene carbonate , a symmetric acyclic carbon methyl methanesulfonate , sulfolane , and sulfolene and the ate , and an asymmetric acyclic carbonate , such as a combi like . nation of ethylene carbonate , dimethyl carbonate, and ethyl Of those compounds , the acyclic or cyclic carbonates or methyl carbonate , a combination of ethylene carbonate , the acyclic or cyclic carboxylic acid esters are preferred 45 diethyl carbonate , and ethyl methyl carbonate , and a com because these compounds are satisfactory in various prop bination of ethylene carbonate , dimethyl carbonate , diethyl erties in a nonaqueous -electrolyte secondary battery. More carbonate , and ethyl methyl carbonate , or such combinations preferred of these is ethylene carbonate , propylene carbon - which further contain propylene carbonate are preferred ate , dimethyl carbonate , ethyl methyl carbonate , diethyl because these combinations have a satisfactory balance carbonate , ethyl acetate , methyl propionate, ethyl propi - 50 between cycle characteristics and discharge load character onate , or y - butyrolactone. Even more preferred is ethylene istics. Preferred of such combinations are ones in which the carbonate , propylene carbonate , dimethyl carbonate , ethyl asymmetric acyclic carbonate is ethyl methyl carbonate . methyl carbonate , diethyl carbonate , ethyl acetate , methyl Furthermore , the number of carbon atoms of each of the propionate, or y -butyrolactone . alkyl groups constituting each dialkyl carbonate is prefer Those compounds may be used alone or in combination of 55 ably 1 - 2 . two or more thereof. It is , however, preferred to use two or Other examples of preferred mixed solvents are ones more compounds in combination . For example , it is espe containing an acyclic ester. In particular , the cyclic carbon cially preferred to use a high - permittivity solvent, such as a ate /acyclic carbonate mixed solvents which contain an acy cyclic carbonate , in combination with a low -viscosity sol- clic ester are preferred from the standpoint of improving the vent, such as an acyclic carbonate or an acyclic ester. 60 discharge load characteristics of a battery . The acyclic ester A preferred combination of nonaqueous solvents is a especially preferably is methyl acetate , ethyl acetate , or combination consisting mainly of at least one cyclic car - methyl propionate . The proportion by volume of the acyclic bonate and at least one acyclic carbonate. In particular, the ester to the whole nonaqueous solvent is generally 50 or total proportion of the cyclic carbonate and the acyclic higher, preferably 8 % or higher, more preferably 15 % or carbonate to the whole nonaqueous solvent is generally 80 % 65 higher, and is generally 50 % or lower, preferably 35 % or by volume or higher, preferably 85 % by volume or higher, lower , more preferably 30 % or lower, even more preferably more preferably 90 % by volume or higher. The proportion 25 % or lower. US 9 ,853 , 326 B2 107 108 Other preferred examples of the nonaqueous solvent are Processes for producing the specific carbonate also are not ones in which one organic solvent selected from the group particularly limited , and a known process selected at will can consisting of ethylene carbonate , propylene carbonate , buty - be used to produce the carbonate . lene carbonate , y - butyrolactone , and y - valerolactone or a Any one specific carbonate may be incorporated alone mixed solvent composed of two or more organic solvents 5 into nonaqueous electrolyte 3 of the invention , or any selected from the group accounts for at least 60 % by volume desired combination of two or more specific carbonates may of the whole . Such mixed solvents have a flash point of be incorporated thereinto in any desired proportion . preferably 50° C . or higher , especially preferably 70° C . or The amount of the specific carbonate to be incorporated higher . Nonaqueous electrolyte 3 employing this solvent is into nonaqueous electrolyte 3 of the invention is not limited , reduced in solvent vaporization and liquid leakage event and may be any desired value unless this considerably when used at high temperatures. In particular, when such a lessens the effects of invention 3 . It is , however, desirable nonaqueous solvent which includes ethylene carbonate and that the specific carbonate should be incorporated in a y - butyrolactone in a total amount of 80 % by volume or concentration which is generally 0 .01 % by mass or higher, larger, preferably 90 % by volume or larger, based on the 16 preferably 0 . 1 % by mass or higher , more preferably 0 . 3 % by whole nonaqueous solvent and in which the volume ratio of mass or higher, and is generally 70 % by mass or lower, the ethylene carbonate to the y -butyrolactone is from 5 : 95 to preferably 50 % by mass or lower ,more preferably 40 % by 45 :55 or such a nonaqueous solvent which includes ethylene mass or lower, based on nonaqueous electrolyte 3 of the carbonate and propylene carbonate in a total amount of 80 % invention . In particular, in the case of a carbonate having an by volume or larger, preferably 90 % by volume or larger , 20 unsaturated bond , it is preferred to incorporate this carbonate based on the whole nonaqueous solvent and in which the in an amount of 10 % by mass or smaller based on nonaque volume ratio of the ethylene carbonate to the propylene ous electrolyte 3 . carbonate is from 30 :70 to 80 :20 is used , then an improved When the amount of the specific carbonate is below the balance between cycle characteristics and discharge load lower limit of that range , there are cases where use of this characteristics , etc . is generally obtained . 25 nonaqueous electrolyte 3 of the invention in a nonaqueous < 1 - 4 . Monofluorophosphate and Difluorophosphate > electrolyte secondary battery results in difficulties in pro Nonaqueous electrolyte 3 of the invention contains a ducing the effect of sufficiently improving the cycle char monofluorophosphate and / or a difluorophosphate as an acteristics of the nonaqueous - electrolyte secondary battery . essential component. With respect to the " monofluorophos On the other hand , when the proportion of the specific phate and difluorophosphate ” to be used in invention 3 , the 30 carbonate is too high , there is a tendency that use of this kinds and contents thereof, places where the salts exist , nonaqueous electrolyte 3 of the invention in a nonaqueous methods of analysis , production process, etc . are the same as electrolyte secondary battery results in decreases in the those described above with regard to nonaqueous electrolyte high - temperature storability and continuous - charge charac teristics of the nonaqueous - electrolyte secondary battery. In < 1 - 5 . Additives > 35 particular, there are cases where gas evolution is enhanced Nonaqueous electrolyte 3 of the invention may contain and capacity retentivity decreases . various additives so long as these additives do not consid < 1 - 5 - 1 - 1 . Unsaturated Carbonate > erably lessen the effects of invention 3 . In the case where The carbonate having an unsaturated bond (hereinafter additives are additionally incorporated to prepare the non - often referred to as “ unsaturated carbonate ” ) as one form of aqueous electrolyte , conventionally known additives can be 40 the specific carbonate according to invention 3 is not limited used at will. One additive may be used alone , or any desired so long as it is a carbonate having a carbon - carbon double combination of two or more additives in any desired pro - bond , and any desired unsaturated carbonate can be used . portion may be used . Incidentally , carbonates having one or more aromatic rings Examples of the additives include overcharge inhibitors are also included in the carbonate having an unsaturated and aids for improving capacity retentivity and cycle char - 45 bond . acteristics after high -temperature storage . It is preferred to Examples of the unsaturated carbonate include vinylene add a carbonate having at least either of an unsaturated bond carbonate and derivatives thereof, ethylene carbonate and a halogen atom (hereinafter sometimes referred to as derivatives substituted with one or more aromatic rings or " specific carbonate ” ) as an aid for improving capacity with one or more substituents having a carbon - carbon retentivity after high - temperature storage and cycle charac - 50 unsaturated bond , phenyl carbonates , vinyl carbonates , and teristics , among those additives. The specific carbonate and allyl carbonates . other additives are separately explained below . Examples of the vinylene carbonate and derivatives < 1 - 5 - 1 . Specific Carbonate > thereof include vinylene carbonate , methylvinylene carbon The specific carbonate is a carbonate having at least either ate , 4 , 5 -dimethylvinylene carbonate , phenylvinylene car of an unsaturated bond and a halogen atom . The specific 55 bonate , 4 , 5 - diphenylvinylene carbonate , and catechol car carbonate may have an unsaturated bond only or have a bonate , and the like . halogen atom only , or may have both an unsaturated bond Examples of the ethylene carbonate derivatives substi and a halogen atom . tuted with one or more aromatic rings or with one or more The molecular weight of the specific carbonate is not substituents having a carbon - carbon unsaturated bond particularly limited , and may be any desired value unless 60 include vinylethylene carbonate, 4 , 5 - divinylethylene car this considerably lessens the effects of invention 3 . How - bonate , phenylethylene carbonate , and 4 ,5 -diphenylethylene ever, the molecular weight thereof is generally 50 or higher , carbonate , and the like . preferably 80 or higher, and is generally 250 or lower, Examples of the phenyl carbonates include diphenyl preferably 150 or lower. When the molecular weight thereof carbonate , ethyl phenyl carbonate ,methyl phenyl carbonate , is too high , this specific carbonate has reduced solubility in 65 and t -butyl phenyl carbonate, and the like . nonaqueous electrolyte 3 and there are cases where the effect Examples of the vinyl carbonates include divinyl carbon of the carbonate is difficult to produce sufficiently . ate and methyl vinyl carbonate , and the like . US 9 ,853 , 326 B2 109 110 Examples of the allyl carbonates include diallyl carbonate fluoromethyl carbonate , 2 - fluoroethyl difluoromethyl car and allyl methyl carbonate, and the like . bonate , ethyl trifluoromethyl carbonate , 2 - chloroethyl Preferred of these unsaturated carbonates as examples of methyl carbonate , ethyl chloromethyl carbonate , 2 , 2 -dichlo the specific carbonate are the vinylene carbonate and deriva roethyl methyl carbonate , 2 -chloroethyl chloromethyl car tives thereof and the ethylene carbonate derivatives substi - 5 bonate , ethyl dichloromethyl carbonate , 2 , 2 ,2 - trichloroethyl tuted with one or more aromatic rings or with one or more methyl carbonate , 2, 2 -dichloroethyl chloromethyl carbon substituents having a carbon - carbon unsaturated bond . In particular, vinylene carbonate, 4 , 5 - diphenylvinylene carbon ate , 2 - chloroethyl dichloromethyl carbonate , and ethyl ate , 4 , 5 - dimethylvinylene carbonate , or vinylethylene car trichloromethyl carbonate , and the like . bonate is more preferred because these carbonates form a 10 Examples of the diethyl carbonate derivatives include stable interface -protective coating film . ethyl (2 - fluoroethyl) carbonate , ethyl ( 2 ,2 -difluoroethyl ) car < 1 - 5 - 1 - 2 . Halogenated Carbonate > bonate , bis (2 - fluoroethyl ) carbonate , ethyl (2 , 2, 2 -trifluoro On the other hand , the carbonate having a halogen atom ethyl) carbonate , 2 , 2 -difluoroethyl 2 ' - fluoroethyl carbonate, (hereinafter often referred to as “ halogenated carbonate ” ) as bis ( 2 , 2 - difluoroethyl) carbonate , 2 , 2 , 2 - trifluoroethyl- 2 ' one form of the specific carbonate according to inventionion 3163 15 Torfluoroethyl carbonate , 2 , 2, 2 -trifluoroethyl - 2 ', 2 ' - difluoroethyl is not particularly limited so long as it is a carbonate having carbonate , bis ( 2 , 2 , 2 - trifluoroethyl) carbonate , ethyl - ( 2 - chlo a halogen atom , and any desired halogenated carbonate can roethyl ) carbonate , ethyl- ( 2 ,2 -dichloroethyl ) carbonate , bis be used . ( 2 - chloroethyl ) carbonate, ethyl- ( 2 , 2 , 2 - trichloroethyl) car Examples of the halogen atoms include fluorine, chlorine , bonate , 2 , 2 -dichloroethyl - 2 - chloroethyl carbonate , bis ( 2 , 2 bromine, and iodine atoms. Preferred of these are fluorine 20 dichloroethyl) carbonate , 2 , 2 , 2 - trichloroethyl - 2 - chloroethyl atoms or chlorine atoms. Especially preferred are fluorine carbonate, 2 , 2 , 2 - trichloroethyl 2 ' , 2 ' -dichloroethyl carbonate , atoms. The number of halogen atoms possessed by the and bis ( 2 , 2 , 2 - trichloroethyl ) carbonate , and the like. halogenated carbonate also is not particularly limited so long Preferred of these halogenated carbonates are the carbon as the number thereof is 1 or larger. However, the number ates having a fluorine atom . More preferred are the carbon thereof is generally 6 or smaller, preferably 4 or smaller. In 25 ate derivatives having a fluorine atom . In particular , fluoro the case where the halogenated carbonate has two or more ethylene carbonate , 4 - ( fluoromethyl) - ethylene carbonate , halogen atoms, these atoms may be the same or different. 4 ,4 -difluoroethylene carbonate , and 4 ,5 - difluoroethylene Examples of the halogenated carbonate include ethylene carbonate are more suitable because these carbonates form carbonate derivatives , dimethyl carbonate derivatives , ethyl an interface -protective coating film . methyl carbonate derivatives, and diethyl carbonate deriva - 30 < 1 - 5 - 1 - 3 . Halogenated Unsaturated Carbonate > tives . Furthermore usable as the specific carbonate is a carbon Examples of the ethylene carbonate derivatives include ate having both an unsaturated bond and a halogen atom fluoroethylene carbonate , chloroethylene carbonate , 4 , 4 - di- (referred to as “ halogenated unsaturated carbonate " ) . This fluoroethylene carbonate , 4 , 5 - difluoroethylene carbonate , halogenated unsaturated carbonate is not particularly lim 4 , 4 - dichloroethylene carbonate , 4 , 5 - dichloroethylene car - 35 ited , and any desired halogenated unsaturated carbonate can bonate , 4 - fluoro - 4 -methylethylene carbonate , 4 - chloro - 4 - be used unless the effects of invention 3 are considerably methylethylene carbonate , 4 ,5 -difluoro -4 -methylethylene lessened thereby. carbonate , 4 , 5 - dichloro - 4 -methylethylene carbonate , Examples of the halogenated unsaturated carbonate 4 - fluoro - 5 -methylethylene carbonate , 4 - chloro - 5 -methyleth - include vinylene carbonate derivatives , ethylene carbonate ylene carbonate , 4 , 4 - difluoro - 5 -methylethylene carbonate , 40 derivatives substituted with one or more aromatic rings or 4 , 4 - dichloro - 5 -methylethylene carbonate , 4 - ( fluoromethyl) with one or more substituents having a carbon - carbon ethylene carbonate , 4 - chloromethyl) - ethylene carbonate , unsaturated bond , and allyl carbonates . With respect to the 4 - ( difluoromethyl) - ethylene carbonate , 4 - ( dichloromethyl) - “ halogenated unsaturated carbonate ” in nonaqueous electro ethylene carbonate , 4 - ( trifluoromethyl) - ethylene carbonate , lyte 3 , the same explanation as that given above with regard 4 - trichloromethyl ) - ethylene carbonate , 4 - ( fluoromethyl) - 4 - 45 to nonaqueous electrolyte 2 applies . fluoroethylene carbonate , 4 -( chloromethyl) - 4 - chloroethyl- < 1 - 5 - 2 . Other Additives > ene carbonate , 4 - ( fluoromethyl) - 5 - fluoroethylene carbonate , Additives other than the specific carbonate are explained 4 -( chloromethyl) -5 - chloroethylene carbonate , 4 - fluoro - 4 ,5 - below . Examples of additives other than the specific car dimethylethylene carbonate , 4 - chloro - 4 , 5 - dimethylethylene bonate include overcharge inhibitors and aids for improving carbonate , 4, 5 - difluoro - 4, 5 -dimethylethylene carbonate , 50 capacity retentivity after high - temperature storage and cycle 4 , 5 - dichloro - 4 , 5 - dimethylethylene carbonate , 4 , 4 -difluoro - characteristics . 5 ,5 -dimethylethylene carbonate , and 4 ,4 -dichloro -5 , 5 - dim - < 1 -5 -2 - 1. Overcharge Inhibitor > ethylethylene carbonate , and the like . Examples of the overcharge inhibitor, content thereof, Examples of the dimethyl carbonate derivatives include examples of combinations in the case of using compounds in fluoromethyl methyl carbonate , difluoromethyl methyl car - 55 different classes in combination , effects of the incorporation bonate , trifluoromethyl methyl carbonate , bis ( fluoromethyl) thereof, etc . are the same as those described above with carbonate , bis ( difluoromethyl ) carbonate , bis (trifluorom - regard to nonaqueous electrolyte 1 . ethyl) carbonate , chloromethyl methyl carbonate , dichlo - < 1 -4 - 2 . Other Additives > romethyl methyl carbonate , trichloromethyl methyl carbon Examples of additives other than the specific carbonate ate , bis ( chloromethyl) carbonate , bis ( dichloromethyl) 60 include overcharge inhibitors and aids for improving capac carbonate , and bis ( trichloromethyl ) carbonate , and the like . ity retentivity after high - temperature storage and cycle char Examples of the ethyl methyl carbonate derivatives acteristics. The " overcharge inhibitors” and the “ aids for include improving capacity retentivity after high - temperature stor 2 - fluoroethyl methyl carbonate , ethyl fluoromethyl carbon age and cycle characteristics” are the same as those ate , 2 , 2 - difluoroethyl methyl carbonate , 2 - fluoroethyl fluo - 65 described above with regard to nonaqueous electrolyte 1 . It romethyl carbonate , ethyl difluoromethyl carbonate , 2 , 2 , 2 - is , however , noted that the " compound A of invention 3 ” is trifluoroethyl methyl carbonate , 2 , 2 - difluoroethyl excluded from the other additives. US 9 ,853 , 326 B2 111 112 < 1 - 5 - 2 - 2 . Aids > with regard to the electrolyte in nonaqueous electrolyte 1 . Examples of the aids for improving capacity retentivity Specifically , the following are included in preferred after high - temperature storage include and cycle character - examples. istics Preferred examples thereof include carbonate compounds other than the specific carbonates, 5 inorganic lithium salts such as LiPF and LiBF4 etc . ; fluo such as erythritan carbonate and spiro -bis - dimethylene car - rine - containing organic lithium salts such as LiCF2SO2, bonate etc . ; sulfur - containing compounds such as ethylene LiN (CF SO2) 2, LiN (C2F SO2) 2 , the lithium salt of cyclic sulfite , 1 , 3 - propanesultone, 1 , 4 -butanesultone , methyl meth 1 , 2 - perfluoroethanedisulfonylimide, the lithium salt of anesulfonate , sulfolane, sulfolene , dimethyl sulfone , diphe cyclic 1 , 3 -perfluoropropanedisulfonylimide , LiN (CF2SO2 ) nyl sulfone, methyl phenyl sulfone, tetramethylthiuramm 10 (C4F , SO2) LiC (CF2SO2 ) 3 , LiPF4( CF3 ) 2 , LiPF4 ( C2F5) 2 , monosulfide , N , N -dimethylmethanesulfonamide , and N , N LiPF4 (CF2SO2 ) 2, LiPF _ (C2F5S02 ) 2, LiBF2 ( CF3) 2 , LiBF2 diethylmethanesulfonamide etc . ; (C2F3 ) 2, LiBF2 (CF3S02 ) 2 , and LiBF2 (C2F2SO2 ) 2 etc . ; and nitrogen - containing compounds such as 1 -methyl - 2 - pyrro lithium bis ( oxalato )borate etc . lidinone, 1 -methyl - 2 - piperidone , 3 -methyl - 2 -oxazolidinone , 15 (CE Preferred . SO . ) . . orof theseLiN ( C isF SOLiPF6 , ) , , fromLiBF4 the , LiCF2SO3 standpoint, LiN of 1 ,3 -dimethyl - 2 - imidazolidinone, and N -methylsuccinimide improving battery performances . Especially preferred is etc . ; and LiPF , or LiBF2. These lithium salts may be used alone or in hydrocarbon compounds such as heptane , octane , and cyclo combination of two or more thereof. One preferred example heptane etc . in the case of using two or more lithium salts in combination [ 2 . Nonaqueous- Electrolyte Secondary Battery ] 20 is a combination of LiPF , and LiBF4. This combination has Nonaqueous - electrolyte secondary battery 3 of the inven - the effect of improving cycle characteristics . In this case, the tion includes : a negative electrode and a positive electrode proportion of the LiBF4 to the sum of the two is preferably which are capable of occluding and releasing ions; and the 0 .01 % by mass or higher, especially preferably 0 . 1 % by nonaqueousnd electrolyte 3 of the invention . mass or higher, and is preferably 20 % by mass or lower, < 2 - 1 . Battery Constitution > 25 especially preferably 5 % by mass or lower. When the Nonaqueous- electrolyte secondary battery 3 of the inven - proportion thereof is lower than the lower limit , there are tion may have the same battery constitution as that described cases where the desired effect is not obtained . In case where above with regard to nonaqueous- electrolyte secondary bat the proportion thereof exceeds the upper limit , battery tery 1 . characteristics after high - temperature storage tend to 30 decrease . < 2 - 2 . Nonaqueous Electrolyte > Another example is a combination of an inorganic lithium As the nonaqueous electrolyte , the nonaqueous electrolyte salt and a fluorine -containing organic lithium salt. In this 3 of the invention described above is used . Incidentally , a case , the proportion of the inorganic lithium salt to the sum mixture of nonaqueous electrolyte 3 of the invention and of the two is desirably from 70 % by mass to 99 % by mass . another nonaqueous electrolyte may be used so long8 as this 2535 The fluorine - containing organic lithium salt preferably is is not counter to the spirit of invention 3 . any of LiN (CF2SO2 ) 2 , LiN (C2F -SO2 ) 2 , the lithium salt of < 2 - 3 . Negative Electrode > cyclic 1 , 2 -perfluoroethanedisulfonylimide , and the lithium The negative electrode of nonaqueous -electrolyte second salt of cyclic 1, 3 -perfluoropropanedisulfonylimide . Use of ary battery 3 may be the same as the negative electrode this combination has the effect of inhibiting the deterioration described above with regard to nonaqueous- electrolyte sec - 40 caused by high - temperature storage . ondary battery 1. The concentration of these electrolytes in nonaqueous < 2 - 4 . Positive Electrode > electrolyte 4 is not particularly limited . However , the con The positive electrode of nonaqueous- electrolyte second centration thereof is generally 0 . 5 mol/ L or higher , prefer ary battery 3 may be the same as the positive electrode a bly 0 . 6 mol/ L or higher, more preferably 0 . 7 mol/ L or described above with regard to nonaqueous - electrolyte sec - 45 higher. The upper limit thereof is generally 3 mol/ L or lower, ondary battery 1 . preferably 2 mol/ L or lower, more preferably 1 . 8 mol/ L or < 2 - 5 . Separator> lower, especially preferably 1 . 5 mol / L or lower. When the The separator of nonaqueous- electrolyte secondary bat concentration of the electrolytes is too low , there are cases tery 3 may be the sameas the separator described above with where this electrolyte has insufficient electrical conductivity . regard to nonaqueous - electrolyte secondary battery 1 . 50 On the other hand , when the concentration thereof is too < 2 -6 . Battery Design > high , there are cases where an increase in viscosity results The battery design of nonaqueous- electrolyte secondary and this reduces electrical conductivity . There also are cases battery 3 may be the same as the battery design described where battery performances decrease. above with regard to nonaqueous- electrolyte secondary bat Nonaqueous electrolyte 4 of the invention includes an tery 1 . 55 electrolyte and a nonaqueous solvent containing the elec [ 1. Nonaqueous Electrolyte 4 ] trolyte dissolved therein . This nonaqueous electrolyte 4 at Like ordinary nonaqueous electrolytes , nonaqueous elec - least contains a cyclic sulfone compound , “ a compound trolyte 4 of the invention includes an electrolyte and a having a coefficient of viscosity at 25° C . of 1 . 5 mPa. s or nonaqueous solvent containing the electrolyte dissolved lower ” , and “ at least one compound selected from the group therein . Usually , the electrolyte and the solvent are con - 60 consisting of carbonates having an unsaturated bond , car tained as main components . bonates having a halogen atom ,monofluorophosphates , and < 1 - 1 . Electrolyte > difluorophosphates ” . As the electrolyte in invention 4 , one or more lithium salts < 1 - 2 . Cyclic Sulfone Compound > are generally used . The lithium salts are not particularly The " cyclic sulfone compound ” is not particularly limited limited so long as they are known to be usable in this 65 so long as it is a cyclic compound in which the cyclic moiety application . Any desired such lithium salts can be used is constituted of one or more methylene groups and one or Examples thereof are the same as those enumerated above more sulfone groups. Any desired cyclic sulfone compound US 9 ,853 , 326 B2 113 114 can be used . Preferred of such compounds are ones in which lane, 2 ,4 , 4 -trifluorosulfolane , 2 , 2 , 3 , 3 - tetrafluorosulfolane , the cyclic moiety is constituted of three or more methylene 2 , 2 , 3 , 4 - tetrafluorosulfolane, 2 , 2 , 4 , 4 - tetrafluorosulfolane , groups and one or more sulfone groups and which have a 2 , 2 ,5 , 5 -tetrafluorosulfolane , 2 , 3 , 3 , 4 - tetrafluorosulfolane, molecular weight of 500 or lower. 2 , 3 , 3 ,5 -tetrafluorosulfolane , 2 , 3 , 4 , 4 - tetrafluorosulfolane , Examples of the cyclic sulfone compound include :mono - 5 2 , 3 ,4 , 5 -tetrafluorosulfolane , 2 ,2 , 3, 3 ,4 -pentafluorosulfolane , sulfone compounds including trimethylene sulfone com 2 , 2 , 3 ,3 , 5 -pentafluorosulfolane , 2 , 2 ,3 , 4 , 4 -pentafluorosulfo pounds , tetramethylene sulfone compounds , and hexameth lane, 2 , 2 , 3 , 4 , 5 - pentafluorosulfolane, 2 , 3 , 3 ,4 , 4 -pentafluoro ylene sulfone compounds ; and disulfone compounds sulfolane , 2 , 3 , 3 , 4 , 5 - pentafluorosulfolane , 2 , 2 , 3 , 3 , 4 , 4 including trimethylene disulfone compounds, tetramethyl- hexafluorosulfolane, 2 , 2 , 3 , 3 , 4 , 5 -hexafluorosulfolane , 2 , 2 , 3 , ene disulfone compounds, and hexamethylene disulfone 10 3 , 5 , 5 - hexafluorosulfolane, 2 , 2 , 3 , 4 ,5 , 5 -hexafluorosulfolane , compounds . More preferred of these from the standpoints of 2 , 2 , 3 ,3 , 4 , 4 , 5 -heptafluorosulfolane , 2 , 2 , 3 , 3 , 4 , 5 ,5 - heptafluo permittivity and viscosity are tetramethylene sulfone com - rosulfolane, and octafluorosulfolane . pounds, tetramethylene disulfone compounds, hexamethyl- Examples of sulfolane derivatives having one or more ene sulfone compounds, and hexamethylene disulfone com - alkyl substituents and a fluorine atom include pounds. Especially preferred are tetramethylene sulfone 15 2 - fluoro -3 -methylsulfolane , 2 - fluoro - 2 -methylsulfolane , compounds ( sulfolane compounds ) . 3 - fluoro - 3 -methylsulfolane , 3 - fluoro - 2 -methylsulfolane , The cyclic sulfone compound preferably is sulfolane 4 - fluoro - 3 -methylsulfolane , 4 - fluoro - 2 -methylsulfolane , and / or a sulfolane derivative (hereinafter , the derivative and 5 - fluoro -3 -methylsulfolane , 5- fluoro - 2 -methylsulfolane , sulfolane are sometimes referred to inclusively as " sulfolane 2 -fluoro - 2 , 4 - dimethylsulfolane, 4 - fluoro - 2 , 4 - dimethylsulfo compound ” ) , from the standpoint of producing the effects of 20 lane, 5 - fluoro - 2 , 4 - dimethylsulfolane, 2 , 2 - difluoro - 3 -methyl the invention . Especially preferred of sulfolane derivatives sulfolane , 2 , 3 - difluoro - 3 -methylsulfolane , 2 , 4 -difluoro - 3 are sulfolane derivatives in which one or more of the methylsulfolane, 2 , 5 - difluoro - 3 -methylsulfolane , 3 , 4 hydrogen atoms bonded to the carbon atoms constituting the difluoro -3 -methylsulfolane , 3, 5 - difluoro - 3 -methylsulfolane , sulfolane ring have been replaced with halogen atoms. 4 , 4 -difluoro - 3 -methylsulfolane , 4 , 5 -difluoro - 3 -methylsulfo Furthermore, sulfolane derivatives having one or more alkyl 25 lane , 5 , 5 - difluoro - 3 -methylsulfolane , 2 , 2 , 3 -trifluoro - 3 groups to such a degree as not to lessen the effects of the methylsulfolane , 2 ,2 ,4 -trifluoro - 3 -methylsulfolane , 2 ,2 ,5 invention are also preferred . Moreover , such sulfolane trifluoro - 3 -methylsulfolane , 2 , 3, 4 -trifluoro - 3 derivatives in which one or more of the hydrogen atoms methylsulfolane , 2, 3 ,5 - trifluoro - 3 -methylsulfolane , 2 , 4 ,4 bonded to the carbon atoms constituting the alkyl groups trifluoro - 3 -methylsulfolane , 2, 4 , 5 - trifluoro - 3 have been replaced with halogen atoms are also especially 30 methylsulfolane , 2 , 5 , 5 - trifluoro - 3 -methylsulfolane , 3 , 4 , 4 preferred . trifluoro - 3 -methylsulfolane , 3 ,4 , 5 - trifluoro - 3 Examples of the halogen atoms include fluorine , chlorine , methylsulfolane, 4 , 4 ,5 - trifluoro - 3 -methylsulfolane , 4 , 5 ,5 bromine , and iodine atoms. Preferred of these are fluorine trifluoro - 3 -methylsulfolane , 2 , 2 , 3 , 4 -tetrafluoro - 3 atoms or chlorine atoms. Especially preferred are fluorine methylsulfolane , 2 ,2 , 3, 5 -tetrafluoro - 3 -methylsulfolane , 2 ,2 , atoms. These ( especially ) preferred halogen atoms apply to 35 4 , 4 - tetrafluoro - 3 -methylsulfolane , 2 , 2 , 4 , 5 -tetrafluoro - 3 both the halogen atoms bonded to the carbon atoms consti - methylsulfolane , 2 , 2 , 5 , 5 - tetrafluoro - 3 -methylsulfolane , 2 ,3 , tuting the sulfolane ring and the halogen atomsbonded to the 4 , 4 - tetrafluoro - 3 -methylsulfolane , 2 , 3 , 4 , 5 - tetrafluoro - 3 alkyl group ( s ) bonded to the sulfolane ring . methylsulfolane , 2 , 3 , 5 , 5 - tetrafluoro - 3 -methylsulfolane , 3 , 4 , Examples of sulfolane derivatives containing one or more 4 , 5 -tetrafluoro - 3 -methylsulfolane , 3 ,4 , 5 , 5 -tetrafluoro - 3 alkyl substituents include 40 methylsulfolane , 4 , 4 , 5 , 5 - tetrafluoro - 3 -methylsulfolane , 2 . 2 , 2 -methylsulfolane , 3 -methylsulfolane , 2 , 2 - dimethylsulfo 3 , 4 , 4 -pentafluoro - 3 -methylsulfolane , 2 , 2 ,3 , 4 , 5 -pentafluoro lane , 3 , 3 - dimethylsulfolane , 2 , 3 - dimethylsulfolane, 2 , 4 - di- 3 -methylsulfolane , 2 , 2 , 3 , 5 , 5 - pentafluoro - 3 -methylsulfolane , methylsulfolane , 2 , 5 - dimethylsulfolane, 2 , 2 , 3 - trimethylsul 2 , 3 ,4 , 4 , 5 - pentafluoro - 3 -methylsulfolane , 2 , 3 , 4 , 5 , 5 -penta folane , 2 , 2 , 4 - trimethylsulfolane , 2 , 2 , 5 - trimethylsulfolane , fluoro - 3 -methylsulfolane , 2 , 2 , 3 , 4 , 4 , 5 - hexafluoro - 3 -methyl 2 , 3 , 3 - trimethylsulfolane , 3 , 3 , 4 - trimethylsulfolane , 3 , 3 , 5 - 45 sulfolane, 2 , 2 , 3 , 4 , 5 , 5 -hexafluoro - 3 - methylsulfolane , 2 , 3 , 4 , trimethylsulfolane , 2 , 3 , 4 - trimethylsulfolane, 2 , 3 , 5 - trimeth - 4 , 5 , 5 -hexafluoro - 3 -methylsulfolane , and heptafluoro - 3 ylsulfolane , 2 , 2 , 3 , 3 - tetramethylsulfolane , 2 , 2 , 3 , 4 - tetrameth - methylsulfolane , and the like . ylsulfolane, 2, 2, 3 ,5 - tetramethylsulfolane, 2, 2 ,4 , 4 - Examples of sulfolane derivatives having a monofluoro tetramethylsulfolane , 2 , 2 , 4 , 5 - tetramethylsulfolane , 2 , 2 , 5 , 5 - alkyl substituent and a fluorine atom include tetramethylsulfolane, 2 ,3 , 3 ,4 - tetramethylsulfolane , 2 , 3 , 3 , 5 - 50 2 - fluoro - 3 - ( fluoromethyl) sulfolane , 3 - fluoro - 3 - ( fluorom tetramethylsulfolane , 2 , 3 , 4 , 4 - tetramethylsulfolane, 2 , 3 , 4 , 5 ethyl) sulfolane, 4 - fluoro - 3 - ( fluoromethyl) sulfolane , tetramethylsulfolane , 3 , 3 , 4 , 4 - tetramethylsulfolane , 2 , 2 , 3 , 3 , 5 - fluoro - 3 - ( fluoromethyl) sulfolane , 2 , 2 - difluoro - 3 - ( fluo 4 -pentamethylsulfolane , 2 , 2 ,3 , 3 , 5 -pentamethylsulfolane , romethyl) sulfolane , 2, 3 -difluoro - 3 -( fluoromethyl) sulfolane , 2 , 2 , 3 , 4 , 4 - pentamethylsulfolane , 2 , 2 , 3 , 4 , 5 -pentamethylsulfo 2 , 4 -difluoro - 3 - ( fluoromethyl) sulfolane , 2 , 5 - difluoro - 3 lane, 2 , 3 , 3 , 4 , 4 -pentamethylsulfolane , 2 , 3 , 3 , 4 , 5 -pentameth - 55 ( fluoromethyl ) sulfolane, 3 , 4 - difluoro - 3 - ( fluoromethyl ) sul ylsulfolane, 2 , 2 , 3 , 3 , 4 , 4 -hexamethylsulfolane , 2 , 2 , 3 , 3 , 4 , 5 folane, 3 , 5 - difluoro - 3 - ( fluoromethyl) sulfolane, 4 , 4 - difluoro hexamethylsulfolane , 2 , 2 , 3 , 3 , 5 , 5 -hexamethylsulfolane , 2 , 2 , 3 - ( fluoromethyl) sulfolane , 4 , 5 - difluoro - 3 - ( fluoromethyl) 3 , 4 , 5 , 5 -hexamethylsulfolane , 2 , 2 , 3 , 3 , 4 , 4 , 5 sulfolane , 5 , 5 -difluoro - 3 - ( fluoromethyl) sulfolane, 2 , 2 ,3 heptamethylsulfolane, 2 ,2 , 3, 3 ,4 , 5 ,5 -heptamethylsulfolane , trifluoro - 3 -( fluoromethyl) sulfolane , 2 , 2 ,4 - trifluoro - 3 and octamethylsulfolane , and the like . 60 ( fluoromethyl sulfolane , 2 , 2 , 5 -trifluoro - 3 - ( fluoromethyl) Examples of sulfolane derivatives having no substituents sulfolane , 2 , 3 , 4 - trifluoro - 3 - ( fluoromethyl) sulfolane , 2 , 3 , 5 and containing a fluorine atom include trifluoro - 3 - ( fluoromethyl) sulfolane , 2 , 4 , 4 -trifluoro - 3 2 - fluorosulfolane, 3 - fluorosulfolane , 2 , 2 -difluorosulfolane , ( fluoromethyl) sulfolane , 2 ,4 , 5 - trifluoro - 3 - ( fluoromethyl ) 2 , 3 -difluorosulfolane , 2 , 4 - difluorosulfolane , 2 , 5 - difluoro - sulfolane, 2 , 5 , 5 - trifluoro - 3 - ( fluoromethyl) sulfolane , 3 , 4 , 4 sulfolane, 3 , 4 -difluorosulfolane , 2 , 2 , 3 - trifluorosulfolane , 65 trifluoro - 3 - ( fluoromethyl ) sulfolane , 3 , 4 , 5 - trifluoro - 3 2 , 3 , 3 - trifluorosulfolane, 2 , 2 , 4 - trifluorosulfolane , 2 , 2 , 5 - trif ( fluoromethyl) sulfolane, 4 , 4 , 5 - trifluoro - 3 - ( fluoromethyl) luorosulfolane, 2 , 3 , 4 - trifluorosulfolane, 2 , 3 ,5 -trifluorosulfo - sulfolane, 4 , 5 , 5 - trifluoro - 3 - ( fluoromethyl) sulfolane, 2 , 2 , 3 , 4 US 9 ,853 , 326 B2 115 116 tetrafluoro - 3 -( fluoromethyl) sulfolane , 2 ,2 , 3, 5 -tetrafluoro - 3 - 2 - fluoro -3 -( trifluoromethyl) sulfolane , 3 - fluoro - 3 -( trifluo ( fluoromethyl) sulfolane , 2 ,2 , 4 , 4 -tetrafluoro - 3 - romethyl) sulfolane, 4 - fluoro -3 -( trifluoromethyl ) sulfolane , ( fluoromethyl) sulfolane, 2 , 2 , 4 , 5 - tetrafluoro - 3 5 - fluoro - 3 - ( trifluoromethyl) sulfolane , 2 , 2 - difluoro - 3 - ( trif ( fluoromethyl) sulfolane , 2 , 2 , 5 , 5 - tetrafluoro - 3 luoromethyl) sulfolane , 2 ,3 -difluoro - 3 -( trifluoromethyl) sul ( fluoromethyl) sulfolane , 2 , 3, 4 ,4 - tetrafluoro -3 - 5 folane , 2 ,4 -difluoro - 3 -( trifluoromethyl) sulfolane , 2, 5 -dif ( fluoromethyl ) sulfolane , 2 , 3 , 4 ,5 - tetrafluoro - 3 luoro - 3 -( trifluoromethyl) sulfolane , 3 , 4 -difluoro - 3 ( fluoromethyl) sulfolane , 2 , 3 , 5 , 5 - tetrafluoro - 3 - ( trifluoromethyl) sulfolane , 3 , 5 - difluoro - 3 - ( trifluoromethyl) ( fluoromethyl) sulfolane , 3 ,4 , 4, 5 - tetrafluoro -3 sulfolane , 4 , 4 -difluoro - 3 -( trifluoromethyl) sulfolane , 4, 5 ( fluoromethyl) sulfolane , 3 , 4 , 5 , 5 - tetrafluoro - 3 difluoro - 3 -( trifluoromethyl) sulfolane , 5 ,5 -difluoro -3 ( fluoromethyl) sulfolane , 4 , 4 , 5 , 5 - tetrafluoro - 3 - 10 (trifluoromethyl ) sulfolane , 2 ,2 , 3 -trifluoro -3 ( fluoromethyl) sulfolane , 2 , 2 , 3 , 4 , 4 - pentafluoro - 3 - (trifluoromethyl ) sulfolane , 2 ,2 , 4 - trifluoro -3 ( fluoromethyl) sulfolane , 2 , 2 , 3 , 4 , 5 - pentafluoro - 3 ( trifluoromethyl) sulfolane , 2 , 2 , 5 - trifluoro - 3 ( fluoromethyl ) sulfolane, 2 , 2 , 3 , 5 , 5 - pentafluoro - 3 (trifluoromethyl sulfolane , 2 , 3 , 4 - trifluoro - 3 ( fluoromethyl )sulfolane , 2 , 3 , 4 , 4 , 5 -pentafluoro - 3 15 (trifluoromethyl ) sulfolane , 2 ,3 , 5 - trifluoro -3 ( fluoromethyl ) sulfolane , 2 , 3 , 4 , 5 , 5 -pentafluoro - 3 ( trifluoromethyl) sulfolane , 2 , 4 , 4 - trifluoro - 3 ( fluoromethyl) sulfolane, 2 , 2 , 3 , 4 , 4 , 5 -hexafluoro - 3 - ( trifluoromethyl ) sulfolane , 2 , 4 , 5 - trifluoro - 3 ( fluoromethyl) sulfolane, 2 , 2 , 3 , 4 , 5 , 5 - hexafluoro - 3 - (trifluoromethyl ) sulfolane , 2 , 5 , 5 - trifluoro - 3 ( fluoromethyl ) sulfolane , 2 , 3 , 4 , 4 ,5 , 5 -hexafluoro - 3 ( trifluoromethyl) sulfolane , 3 , 4 , 4 - trifluoro - 3 ( fluoromethyl ) sulfolane, and heptafluoro - 3 - ( fluoromethyl) 20 ( trifluoromethyl ) sulfolane , 3 , 4 , 5 -trifluoro - 3 sulfolane , and the like . ( trifluoromethyl) sulfolane , 4 , 4 , 5 - trifluoro - 3 Examples of sulfolane derivatives having a difluoroalkyl ( trifluoromethyl) sulfolane , 4 ,5 ,5 - trifluoro - 3 substituent and a fluorine atom include ( trifluoromethyl) sulfolane , 2 ,2 , 3 , 4 -tetrafluoro - 3 2 - fluoro - 3 - ( difluoromethyl ) sulfolane , 3 - fluoro - 3 - ( difluo (trifluoromethyl sulfolane , 2 , 2 , 3 , 5 - tetrafluoro - 3 romethyl ) sulfolane , 4 - fluoro - 3 - ( difluoromethyl) sulfolane , 25 ( trifluoromethyl) sulfolane , 2 , 2 , 4 , 4 - tetrafluoro - 3 5 - fluoro - 3 -( difluoromethyl ) sulfolane, 2 ,2 - difluoro - 3 - (dif (trifluoromethyl ) sulfolane , 2 , 2 ,4 , 5 - tetrafluoro - 3 luoromethyl sulfolane , 2 , 3 - difluoro - 3 - ( difluoromethyl sul ( trifluoromethyl ) sulfolane, 2 , 2 , 5 , 5 - tetrafluoro - 3 folane , 2 , 4 - difluoro - 3 - ( difluoromethyl) sulfolane , 2 , 5 - dif - (trifluoromethyl ) sulfolane , 2 , 3 , 4 , 4 - tetrafluoro - 3 luoro - 3 - (difluoromethyl ) sulfolane , 3 ,4 - difluoro -3 (trifluoromethyl ) sulfolane , 2 , 3 , 4 , 5 -tetrafluoro - 3 ( difluoromethyl) sulfolane , 3 , 5 - difluoro - 3 - (difluoromethyl ) 30 ( trifluoromethyl) sulfolane , 2 , 3 , 5 , 5 - tetrafluoro - 3 sulfolane , 4 ,4 - difluoro - 3 - ( difluoromethyl) sulfolane, 4 , 5 ( trifluoromethyl) sulfolane , 3 , 4 , 4 , 5 - tetrafluoro - 3 difluoro - 3 - ( difluoromethyl) sulfolane , 5 , 5 - difluoro - 3 ( trifluoromethyl )sulfolane , 3 , 4 , 5 ,5 -tetrafluoro -3 ( difluoromethyl) sulfolane , 2 ,2 , 3 - trifluoro -3 - ( trifluoromethyl) sulfolane , 4 ,4 , 5 , 5 -tetrafluoro -3 ( difluoromethyl) sulfolane , 2 , 2 , 4 - trifluoro - 3 (trifluoromethyl ) sulfolane , 2 , 2 , 3 , 4 , 4 -pentafluoro - 3 ( difluoromethyl) sulfolane , 2 ,2 , 5 - trifluoro - 3 - 35 ( trifluoromethyl) sulfolane , 2 , 2 , 3 ,4 , 5 -pentafluoro - 3 ( difluoromethyl) sulfolane , 2 , 3 , 4 -trifluoro - 3 - ( trifluoromethyl )sulfolane , 2 , 2 , 3 , 5 , 5 -pentafluoro - 3 ( difluoromethyl )sulfolane , 2 , 3 , 5 -trifluoro - 3 ( trifluoromethyl) sulfolane , 2 , 3 ,4 , 4 , 5 -pentafluoro - 3 (difluoromethyl ) sulfolane , 2 , 4 ,4 - trifluoro - 3 - ( trifluoromethyl) sulfolane , 2 , 3 , 4 , 5 , 5 - pentafluoro - 3 ( difluoromethyl) sulfolane , 2 , 4 , 5 -trifluoro - 3 ( trifluoromethyl) sulfolane , 2 , 2 , 3 , 4 , 4 , 5 - hexafluoro - 3 ( difluoromethyl ) sulfolane , 2 , 5 , 5 -trifluoro - 3 - 40 ( trifluoromethyl) sulfolane , 2 , 2 , 3 , 4 , 5 , 5 - hexafluoro - 3 ( difluoromethyl) sulfolane , 3 , 4 , 4 - trifluoro - 3 (trifluoromethyl ) sulfolane , 2 , 3 , 4 ,4 , 5 , 5 -hexafluoro - 3 ( difluoromethyl ) sulfolane , 3, 4 ,5 - trifluoro -3 - (trifluoromethyl ) sulfolane, and heptafluoro - 3 ( difluoromethyl )sulfolane , 4 ,4 , 5 - trifluoro -3 - ( trifluoromethyl) sulfolane , and the like . ( difluoromethyl ) sulfolane , 4 ,5 , 5 -trifluoro -3 - More preferred of the sulfolane compounds enumerated (difluoromethyl ) sulfolane , 2 , 2 , 3 , 4 -tetrafluoro - 3 - 45 above are (difluoromethyl ) sulfolane , 2 , 2 , 3 , 5 - tetrafluoro - 3 - sulfolane, 2 -methylsulfolane , 3 -methylsulfolane , 2 , 2 -dim ( difluoromethyl ) sulfolane , 2 , 2 , 4 , 4 - tetrafluoro - 3 ethylsulfolane , 3 , 3 - dimethylsulfolane , 2 , 3 - dimethylsulfo (difluoromethyl ) sulfolane , 2 , 2 , 4 , 5 - tetrafluoro - 3 lane , 2 , 4 - dimethylsulfolane , 2 , 5 - dimethylsulfolane, 2 - fluo ( difluoromethyl) sulfolane , 2 , 2 , 5 , 5 - tetrafluoro - 3 - rosulfolane , 3 - fluorosulfolane, 2 - fluoro - 3 -methylsulfolane , ( difluoromethyl ) sulfolane , 2 , 3 , 4 , 4 - tetrafluoro - 3 - 50 3 - fluoro - 3 -methylsulfolane , 4 - fluoro - 3 -methylsulfolane , ( difluoromethyl) sulfolane , 2 , 3 , 4 , 5 -tetrafluoro - 3 - 5 - fluoro - 3 -methylsulfolane , 2 - fluoro - 2 -methylsulfolane , ( difluoromethyl) sulfolane , 2 , 3 , 5 , 5 - tetrafluoro - 3 - 3 - fluoro - 2 -methylsulfolane , 4 - fluoro - 2 -methylsulfolane . (difluoromethyl ) sulfolane , 3 , 4 , 4 ,5 - tetrafluoro -3 5 - fluoro - 2 -methylsulfolane , 2 - fluoro - 2 , 4 - dimethylsulfolane , ( difluoromethyl) sulfolane , 3 , 4 , 5 , 5 - tetrafluoro - 3 - 3 - fluoro - 2 , 4 -dimethylsulfolane , 4 - fluoro - 2 , 4 - dimethylsulfo ( difluoromethyl )sulfolane , 4 , 4 , 5 , 5 - tetrafluoro - 3 - 55 lane, and 5 - fluoro - 2 , 4 - dimethylsulfolane . (difluoromethyl ) sulfolane , 2 , 2 , 3 ,4 , 4 -pentafluoro - 3 Especially preferred are ( difluoromethyl) sulfolane , 2 , 2 , 3 , 4 , 5 -pentafluoro - 3 - sulfolane, 2 -methylsulfolane , 3 -methylsulfolane , 2 - fluoro ( difluoromethyl) sulfolane , 2 ,2 , 3 , 5 ,5 -pentafluoro -3 sulfolane , 3 - fluorosulfolane, 2 - fluoro - 3 -methylsulfolane , ( difluoromethyl) sulfolane , 2 , 3 , 4 , 4 , 5 -pentafluoro - 3 - 3 - fluoro - 3 -methylsulfolane , 4 - fluoro - 3 -methylsulfolane , (difluoromethyl ) sulfolane , 2 , 3 ,4 , 5 , 5 -pentafluoro -3 - 60 5 - fluoro - 3 -methylsulfolane , and the like . (difluoromethyl ) sulfolane , 2 , 2 , 3 , 4 , 4 , 5 -hexafluoro - 3 In case where a cyclic sulfone compound which has been ( difluoromethyl) sulfolane , 2 , 2 , 3 , 4 , 5 , 5 - hexafluoro - 3 - excessively alkyl- substituted is used , the result is an increase (difluoromethyl ) sulfolane , 2 , 3 , 4 , 4 , 5 , 5 - hexafluoro - 3 - in the coefficient of viscosity and this causes a decrease in ( difluoromethyl) sulfolane , and heptafluoro - 3 - electrical conductivity . In case where a cyclic sulfone com (difluoromethyl ) sulfolane , and the like . 65 pound which has been excessively fluorinated is used , this Examples of sulfolane derivatives having a trifluoroalkyl compound used in a nonaqueous - electrolyte battery has substituent and a fluorine atom include reduced chemical stability or reduced solubility in other US 9 ,853 , 326 B2 117 118 solvents . There are hence cases where it is difficult to ethane, ethylene glycol di- n - propyl ether, ethylene glycol sufficiently produce the effects of the invention . di- n -butyl ether , and diethylene glycol dimethyl ether , and Any one of the cyclic sulfone compoundscompounds enumeratedenumerated the like . above may be incorporated alone into nonaqueous electro Examples of the cyclic ethers having 3 - 6 carbon atoms lyte 4 of the invention , or any desired combination of two or 5 include tetrahydrofuran , 2 -methyltetrahydrofuran , 3 -meth more thereof in any desired proportion may be used . Pro yltetrahydrofuran , 1, 3 -dioxane , 2 -methyl - 1 ,3 -dioxane , 4 -methyl - 1 , 3 -dioxane , and 1 , 4 - dioxane, and the like . cesses for production also are not particularly limited , and a Preferred of the examples of the " compound having a known process selected at will can be used to produce the coefficient of viscosity at 25° C . of 1 . 5 mPa . s or lower ” cyclic sulfone compound . 10 enumerated above are dimethyl carbonate , diethyl carbon It is desirable that the cyclic sulfone compound should be ate , di- n - propyl carbonate , diisopropyl carbonate , n -propyl incorporated into the nonaqueous electrolyte 4 of the inven isopropyl carbonate , ethyl methyl carbonate , methyl n - pro tion in a concentration which is generally 10 % by volume or pyl carbonate , diethyl ether , di- n - propyl ether, di- n -butyl higher , preferably 15 % by volume or higher, more prefer ether , dimethoxymethane , dimethoxyethane , diethoxymeth ably 20 % by volume or higher , and is generally 70 % by 15 ane diethoxyethane . ethoxymethoxymethane . volume or lower, preferably 60 % by volume or lower, more ethoxymethoxyethane, tetrahydrofuran , 2 -methyltetrahydro preferably 50 % by volume or lower, based on the whole furan , 1, 3 - dioxane , 2 -methyl - 1 ,3 - dioxane , 4 -methyl -1 , 3 - di nonaqueous solvent in the electrolyte . When the concentra oxane , 1 , 4 -dioxane , methyl acetate , ethyl acetate , n - propyl tion thereof is lower than the lower limit of that range and acetate , n - butyl acetate , methyl propionate , ethyl propionate , this nonaqueous electrolyte 4 of the invention is used in a 20 n -propyl propionate , n -butyl propionate, methyl butyrate , nonaqueous- electrolyte battery , there are cases where this ethyl butyrate , n -propyl butyrate , methyl isobutyrate , and nonaqueous - electrolyte battery is less apt to have the effect ethyl isobutyrate . of sufficiently improving in safety . In case where the con - Preferred of these is dimethyl carbonate , diethyl carbon centration thereof is higher than the upper limit of that range , ate , ethyl methyl carbonate , dimethoxyethane , there is a tendency that the nonaqueous electrolyte comes to 25 ethoxymethoxyethane , tetrahydrofuran , 2 -methyltetrahydro have an increased coefficient of viscosity and this results in furan , 1 , 3 -dioxane , 1 , 4 - dioxane , methyl acetate , ethyl a decrease in electrical conductivity . Especially when this acetate , methyl propionate , ethyl propionate , methyl nonaqueous - electrolyte battery is charged /discharged at a butyrate , ethyl butyrate , methyl isobutyrate , or ethyl isobu high current density , there are cases where charge /discharge tyrate . Especially preferred of these , from the standpoint of capacity retentivity decreases . 30 decomposition gas evolution during high - temperature bat < 1 - 3 . “ Compound Having Coefficient of Viscosity at 25° C . tery storage , is dimethyl carbonate , diethyl carbonate , ethyl of 1 . 5 mPa. s or lower " > methyl carbonate , methyl acetate , ethyl acetate, methyl It is essential that nonaqueous electrolyte 4 of the inven - propionate , ethyl propionate , methyl butyrate , ethyl tion should contain at least one " compound having a coef- butyrate , methyl isobutyrate , or ethyl isobutyrate . ficient of viscosity at 25° C . of 1 . 5 mPa .s or lower ” . It is 35 Incidentally , the coefficient of viscosity at 25° C . is a preferred that the " compound having a coefficient of vis - value measured with any of a capillary viscometer , falling cosity at 25° C . of 1 . 5 mPa . s or lower ” should be at least one ball viscometer, and vibration viscometer. When the coef compound selected from the group consisting of acyclic f icient of viscosity of the compound , which is a Newtonian carbonates, acyclic carboxylic acid esters, acyclic ethers , fluid , is precisely measured with these viscometers , the same and cyclic ethers , from the standpoint of battery character - 40 value is obtained within an error range for the measure istics in the case of use in a nonaqueous - electrolyte battery . ments . However, it is preferred that the coefficient of vis The acyclic carbonates preferably are ones having 3 - 7 cosity should be measured with a capillary viscometer . carbon atoms. The acyclic carboxylic acid esters preferably Processes for production also are not particularly limited , are ones having 3 - 7 carbon atoms. The acyclic ethers and a known process selected at will can be used to produce preferably are ones having 3 - 10 carbon atoms. The cyclic 45 the compound . ethers preferably are ones having 3 - 6 carbon atoms. Also with respect to the compound having a specific low Examples of the acyclic carbonates having 3 - 7 carbon coefficient of viscosity explained above , any one of the atoms include dimethyl carbonate , diethyl carbonate , di- n examples of the compound may be incorporated alone into propyl carbonate , diisopropyl carbonate , n -propyl isopropyl nonaqueous electrolyte 4 of the invention or any desired carbonate , ethyl methyl carbonate , methyl n -propyl carbon - 50 combination of two or more thereof in any desired propor ate , n - butyl methyl carbonate , isobutyl methyl carbonate , tion may be used . In the case where the “ at least one t - butyl methyl carbonate, ethyl n -propyl carbonate , n -butyl compound selected from the group consisting of carbonates ethyl carbonate , isobutyl ethyl carbonate , and t - butyl ethyl having an unsaturated bond , carbonates having a halogen carbonate , and the like . atom , monofluorophosphates, and difluorophosphates” , Examples of the acyclic carboxylic acid esters having 3 - 7 55 which will be described later, has a coefficient of viscosity carbon atoms includemethyl acetate , ethyl acetate , n - propyl at 25° C . of 1 . 5 mPa. s or lower , then this compound is acetate , isopropyl acetate , n - butyl acetate , isobutyl acetate , regarded also as a “ compound having a coefficient of vis t -butyl acetate ,methyl propionate , ethyl propionate , n -pro cosity at 25° C . of 1 .5 mPa . s or lower” . In this case , when pyl propionate , isopropyl propionate , n - butyl propionate , this compound is used in a proportion of 30 % by volume or isobutyl propionate , t - butyl propionate , methyl butyrate , 60 higher based on the whole nonaqueous electrolyte , the ethyl butyrate, n - propyl butyrate , isopropyl butyrate ,methyl coefficient of viscosity of the nonaqueous electrolyte can be isobutyrate , ethyl isobutyrate , n - propyl isobutyrate , and iso - reduced to a value within a range advantageous for the propyl isobutyrate , and the like . high -current - density charge / discharge characteristics of the Examples of the acyclic ethers having 3 - 10 carbon atoms battery . When the proportion thereof is 8 % by mass or lower include diethyl ether, di- n - propyl ether, di- n -butyl ether, 65 based on the whole nonaqueous electrolyte , an electrode dimethoxymethane , dimethoxyethane , diethoxymethane , surface coating film having high lithium ion conductivity diethoxyethane, ethoxymethoxymethane , ethoxymethoxy - can be formed . US 9 ,853 , 326 B2 119 120 In the invention , the content of the “ compound having a bonate ; sulfolane , ethylene carbonate, diethyl carbonate , and coefficient of viscosity at 25° C . of 1 . 5 mPa. s or lower ” is not ethyl methyl carbonate ; and sulfolane , ethylene carbonate , particularly limited . However, it is desirable to incorporate dimethyl carbonate , diethyl carbonate , and ethyl methyl this compound in a concentration of generally 30 % by carbonate, and the like . volume or higher, preferably 40 % by volume or higher , more 5 Combinations obtained by further adding propylene car preferably 50 % by volume or higher, based on the whole bonate to those combinations including sulfolane , ethylene nonaqueous solvent in the nonaqueous electrolyte . In case carbonate , and one or more acyclic carbonates are also where the concentration thereof is lower than the lower included in preferred combinations. limit , there is a tendency that the nonaqueous electrolyte In the case where propylene carbonate is contained , the comes to have an increased coefficient of viscosity and this 10 volume ratio of the ethylene carbonate to the propylene results in a decrease in electrical conductivity . In particular , carbonate is preferably from 99 : 1 to 40 :60 , especially pref there are cases where the nonaqueous - electrolyte battery has erably from 95 : 5 to 50 : 50 . Furthermore , the proportion of reduced heavy - current discharge characteristics . It is also the propylene carbonate to the whole nonaqueous solvent of desirable to incorporate the compound in a concentration of the electrolyte may be regulated to 0 . 1 % by volume or generally 90 % by volume or lower , preferably 85 % by 15 higher, preferably 1 % by volume or higher, more preferably volume or lower, more preferably 80 % by volume or lower . 2 % by volume or higher, and the upper limit thereofmay be In case where the concentration thereof exceeds the upper regulated to generally 20 % by volume or lower, preferably limit of that range , there is a tendency that this nonaqueous 8 % by volume or lower, more preferably 5 % by volume or electrolyte 4 of the invention has a reduced permittivity and lower. Incorporation of propylene carbonate in an amount this results in a decrease in electrical conductivity . In par - 20 within that range is preferred because this incorporation ticular , there are cases where the nonaqueous - electrolyte brings about even better low - temperature characteristics battery has reduced heavy - current discharge characteristics. while maintaining the properties of the combination of The nonaqueous solvent in nonaqueous electrolyte 4 sulfolane , ethylene carbonate , and one or more dialkyl according to the invention may include a highly polar carbonates. solvent such as , e . g ., a cyclic carbonate , so long as this does 25 In this description , the values of the volumes of nonaque not lessen the effects of the invention . Preferred examples of ous solvents are ones measured at 25° C . However, in the such mixed solvents include a combination composed case of a nonaqueous solvent which is solid at 25° C . , such mainly of a sulfolane compound , an acyclic carbonate , and as , e . g . , ethylene carbonate , the value measured at the a cyclic carbonate , a combination composed mainly of a melting point is used . sulfolane compound , an acyclic ether, and a cyclic carbon - 30 < 1 - 4 . “ At Least One Compound Selected from Group Con ate , and a combination composed mainly of a sulfolane sisting of Carbonates Having Unsaturated Bond ( s ), Carbon compound , an acyclic ester, and a cyclic carbonate . ates Having Halogen Atom ( s ) , Monofluorophosphates, and One preferred combination for constituting a nonaqueous Difluorophosphates " > solvent is a combination consisting mainly of at least one Nonaqueous electrolyte 4 of the invention contains " at sulfolane compound , at least one acyclic carbonate , and at 35 least one compound selected from the group consisting of least one cyclic carbonate . In particular, this combination is carbonates having an unsaturated bond , carbonates having a one in which the total proportion of the sulfolane compound halogen atom , monofluorophosphates, and difluorophos and the cyclic carbonate to the nonaqueous solvent is 15 % phates ” ( hereinafter sometimes referred to as “ specific com by volume or higher, preferably 20 % by volume or higher, pound( s )” ) besides the ingredients described above . Each of more preferably 25 % by volume or higher , and is generally 40 these specific compounds has the ability to form an inter 70 % by volume or lower, preferably 60 % by volume or face -protective coating film . There is hence a conception by lower, more preferably 50 % by volume or lower, the pro - which the specific compounds as components of an electro portion of the volume of the cyclic carbonate to the sum of lyte can be classified in the same group . the sulfolane compound and the cyclic carbonate is 5 % or < 1 -4 - 1 . Carbonates Having Unsaturated Bond ( s )> higher , preferably 10 % by volume or higher, more prefer - 45 The carbonates having an unsaturated bond (hereinafter ably 15 % by volume or higher , and is generally 90 % by sometimes referred to as " unsaturated carbonates " ) are not volume or lower , preferably 80 % by volume or lower, more particularly limited so long as they are carbonates having preferably 70 % by volume or lower , and the proportion of one or more carbon -carbon unsaturated bonds, such as the acyclic carbonate to the nonaqueous electrolyte is gen - carbon -carbon double bonds or carbon - carbon triple bonds . erally 30 % by volume or higher , preferably 40 % by volume 50 Any desired unsaturated carbonate can be used . Incidentally , or higher , more preferably 50 % by volume or higher, and is carbonates having one or more aromatic rings are also generally 90 % by volume or lower, preferably 85 % by included in the carbonates having an unsaturated bond . volume or lower, more preferably 80 % by volume or lower . With respect to the unsaturated carbonates in nonaqueous Use of such combination of nonaqueous solvents is pre electrolyte 4 , the same explanation as that given above with ferred because the battery fabricated with this combination 55 regard to nonaqueous electrolyte 1 applies. has an improved balance between cycle characteristics and < 1 - 4 - 2 . Carbonates Having Halogen Atom ( s ) > high - temperature storability ( in particular , residual capacity On the other hand , the carbonates having a halogen atom and high - load discharge capacity after high - temperature (hereinafter sometimes referred to as “ halogenated carbon storage ) . ates” ) are not particularly limited so long as they are Examples of the preferred combination including at least 60 carbonates having a halogen atom . Any desired halogenated one sulfolane compound , at least one cyclic carbonate , and carbonate can be used . With respect to the halogenated at least one acyclic carbonate include : sulfolane, ethylene carbonates in nonaqueous electrolyte 4 , the same explana carbonate , and dimethyl carbonate ; sulfolane , ethylene car tion as that given above with regard to nonaqueous electro bonate , and diethyl carbonate ; sulfolane, ethylene carbonate , lytes 1 and 2 applies. and ethyl methyl carbonate ; sulfolane , ethylene carbonate, 65 It is also preferred to use a carbonate having both an dimethyl carbonate , and diethyl carbonate; sulfolane , ethyl- unsaturated bond and a halogen atom ( this carbonate is ene carbonate , dimethyl carbonate , and ethyl methyl car- hereinafter sometimes referred to as “ halogenated unsatu US 9 ,853 , 326 B2 121 122 rated carbonate ” ). This halogenated unsaturated carbonate is Examples of the overcharge inhibitor include : aromatic not particularly limited , and any desired halogenated unsatu compounds such as biphenyl, alkylbiphenyls , terphenyl , rated carbonate can be used unless the effects of the inven - partly hydrogenated terphenyls , cyclohexylbenzene, t -butyl tion are considerably lessened thereby . With respect to the benzene, t - amylbenzene, diphenyl ether , and dibenzofuran ; halogenated unsaturated carbonate in nonaqueous electro - 5 products of the partial fluorination of these aromatic com lyte 4 , the same explanation as that given above with regard pounds , such as 2 - fluorobiphenyl, 0 -cyclohexylfluoroben to nonaqueous electrolyte 2 applies. zene , and p - cyclohexylfluorobenzene ; and fluorine - contain The " carbonates having an unsaturated bond ” and the ing anisole compounds such as 2 ,4 -difluoroanisole , 2 ,5 " carbonates having a halogen atom ” are hereinafter inclu - difluoroanisole , 2 , 6 - difluoroanisole , and 3 , 5 - difluoroanisole . sively referred to as " specific carbonates " . The specific 10 Preferred of these are aromatic compounds such as biphenyl, carbonates are not particularly limited in molecular weight, alkylbiphenyls, terphenyl , partly hydrogenated terphenyls , and may have any desired molecular weight unless the cyclohexylbenzene , t -butylbenzene , t - amylbenzene , diphe effects of the invention are considerably lessened thereby . nyl ether, and dibenzofuran . Two or more of these may be However , the molecular weight thereof is generally 50 or used in combination . In the case where two or more com higher, preferably 80 or higher, and is generally 250 or 15 pounds are used in combination , it is especially preferred , lower, preferably 150 or lower. When the molecular weight from the standpoint of a balance between overcharge - inhib thereof is too high , there are cases where such specific iting properties and high -temperature storability , to employ carbonates have reduced solubility in the nonaqueous elec - a combination of cyclohexylbenzene and t -butylbenzene or trolyte , making it difficult to sufficiently produce the effects t - amylbenzene or to use a compound selected from oxygen of the invention . Processes for producing specific carbonates 20 free aromatic compounds such as biphenyl, alkylbiphenyls , also are not particularly limited , and a known process terphenyl, partly hydrogenated terphenyls , cyclohexylben selected at will can be used to produce the carbonates . zene , t -butylbenzene , and t- amylbenzene in combination Any one specific carbonate may be incorporated alone with a compound selected from oxygen -containing aromatic into nonaqueous electrolyte 4 of the invention , or any compounds such as diphenyl ether and dibenzofuran . desired combination of two or more specific carbonates in 25 The proportion of the overcharge inhibitor in nonaqueous any desired proportion may be incorporated . The amount of electrolyte 4 is generally 0 . 1 % by mass or higher , preferably the specific carbonate to be incorporated into the nonaque - 0 . 2 % by mass or higher , especially preferably 0 . 3 % by mass ous electrolyte 4 of the invention is not limited , and the or higher , most preferably 0 . 5 % by mass or higher , based on specific carbonate may be incorporated in any desired the whole nonaqueous electrolyte . The upper limit thereof is amount unless the effects of the invention are considerably 30 generally 5 % by mass or lower , preferably 3 % by mass or lessened thereby . However, it is desirable that the specific lower , especially preferably 2 % by mass or lower . In case carbonate should be incorporated in a concentration which is where the concentration thereof is lower than the lower generally 0 .01 % by mass or higher , preferably 0 . 1 % bymass limit , the overcharge inhibitor produces almost no effect . or higher, more preferably 0 .3 % by mass or higher , and is Conversely , too high concentrations thereof tend to result in generally 8 % by mass or lower , preferably 5 % by mass or 35 a decrease in battery characteristics , e . g . , high - temperature lower, more preferably 3 % by mass or lower, based on the storability. whole nonaqueous electrolyte 4 of the invention . When the < 1- 6 . Aids > proportion thereof is lower than the lower limit of that range Examples of the aids include : carbonate compounds such and this nonaqueous electrolyte 4 of the invention is used in as erythritan carbonate, spiro -bis - dimethylene carbonate , a nonaqueous- electrolyte battery , there are cases where this 40 and methoxyethyl methyl carbonate ; carboxylic acid anhy nonaqueous -electrolyte battery is less apt to have the effect drides such as succinic anhydride , glutaric anhydride ,maleic of sufficiently improving in cycle characteristics. On the anhydride, citraconic anhydride , glutaconic anhydride , other hand , in case where the proportion of the specific itaconic anhydride, diglycolic anhydride, cyclohexanedicar carbonate is too high , use of this nonaqueous electrolyte 4 of boxylic anhydride , cyclopentanetetracarboxylic dianhy the invention in a nonaqueous - electrolyte battery tends to 45 dride , and phenylsuccinic anhydride ; spiro compounds such result in reduced high - temperature storability of this non - as 2 , 4 , 8 , 10 -tetraoxaspiro [ 5 . 5 ] undecane and 3 , 9 - divinyl- 2 , 4 , aqueous- electrolyte battery. In particular, there are cases 8 , 10 - tetraoxaspiro [ 5 . 5 ]undecane ; sulfur -containing com where gas evolution is enhanced and discharge capacity pounds such as ethylene sulfite , 1 , 3 -propanesultone , 1 , 4 retentivity decreases. butanesultone , methyl methanesulfonate , ethyl < 1 - 4 - 3 . Monofluorophosphates and Difluorophosphates > 50 methanesulfonate , busulfan , sulfolene , dimethyl sulfone , With respect to the " monofluorophosphates and difluoro - diphenyl sulfone , N , N - dimethylmethanesulfonamide, and phosphates ” for use in invention 4 , the kinds and contents N , N - diethylmethanesulfonamide; nitrogen - containing com thereof, places where the salts exist, methods of analysis , pounds such as 1 -methyl - 2 -pyrrolinone , 1 -methyl - 2 -piperi production process , etc . are the same as those described done , 3 -methyl - 2 - oxazolidinone , 1 , 3 - dimethyl - 2 - imidazoli above with regard to nonaqueous electrolyte 1 . 55 dinone , and N -methylsuccinimide ; hydrocarbon compounds Nonaqueous electrolyte 4 of the invention can contain such as heptane , octane , nonane , decane, and cycloheptane ; " other compounds ” so long as this does not lessen the effects and fluorine -containing aromatic compounds such as fluo of the invention . Examples of the " other compounds” robenzene , difluorobenzene, hexafluorobenzene , and benzo include various compounds including conventionally known trifluoride . Two or more of these aids may be used in overcharge inhibitors and aids . 60 combination . < 1 - 5 . Overcharge Inhibitor > The proportion of these aids in nonaqueous electrolyte 4 By incorporating an overcharge inhibitor, the battery can is generally 0 .01 % by mass or higher , preferably 0 . 1 % by be inhibited from rupturing/ firing upon overcharge, etc . mass or higher , especially preferably 0 . 2 % by mass or With respect to the overcharge inhibitor in nonaqueous higher, based on the whole nonaqueous electrolyte 4 . The electrolyte 4 , the same explanation as that given above with 65 upper limit thereof is generally 5 % by mass or lower, regard to nonaqueous electrolyte 1 applies. Preferred preferably 3 % by mass or lower, especially preferably 1 % by examples thereof include the following . mass or lower . By adding those aids, capacity retentivity US 9 ,853 , 326 B2 123 124 after high -temperature storage and cycle characteristics can I. Nonaqueous Electrolyte be improved . In case where the concentration thereof is lower than the lower limit, the aids produce almost no effect. Embodiment 5 - 1 Conversely , too high concentrations thereof tend to result in a decrease in battery characteristics , e . g . , high - load dis - 5 Nonaqueous electrolyte 5 of the invention is a nonaque charge characteristics . ous electrolyte which includes a nonaqueous organic solvent < 1 - 7 . Preparation of Nonaqueous Electrolyte > and a lithium salt dissolved therein , and is characterized in Nonaqueous electrolyte 4 according to the invention can that the nonaqueous organic solvent contains a cyclic be prepared by mixing an electrolyte , a cyclic sulfone polyamine compound and / or a cyclic polyamide compound compound , " a compound having a coefficient of viscosity at and further contains at least one compound selected from the 25° C . of 1 . 5 mPa . s or lower ” , and the specific compound group consisting of unsaturated carbonates, fluorine - con optionally together with " other compounds ” to dissolve taining carbonates, monofluorophosphates , and difluoro these ingredients in each other. It is preferred that in pre - phosphates. This electrolyte is referred to as “ embodiment paring nonaqueous electrolyte 4 , each raw material should is15 5 - 1” . be dehydrated beforehand in order to reduce the water [ 1 . Cyclic Polyamine Compound ] content of the electrolyte to be obtained . It is desirable to [ 1 - 1 . Kind ] dehydrate each raw material to generally 50 ppm or lower, The cyclic polyamine compound which may be contained preferably 30 ppm or lower , especially preferably 10 ppm or in nonaqueous electrolyte 5 of the invention (hereinafter lower . It is also possible to conduct dehydration , deacidifi - 20 suitably referred to as " cyclic polyamine compound of cation , and the like after the preparation of an electrolyte . invention 5 ” ) is any of cyclic compounds having a structure Nonaqueous electrolyte 4 of the invention is suitable for formed by the condensation of one or more amines and use as an electrolyte for nonaqueous -electrolyte batteries, in derivatives of such cyclic compounds. Namely, the cyclic particular, for secondary batteries , e . g ., lithium secondary polyamine compound is any of cyclic compounds including batteries . Nonaqueous - electrolyte battery 4 , which employs 25 two or more nitrogen atoms bonded to each other with the electrolyte of the invention , is explained below . alkylene groups and derivatives thereof formed by replacing [ 2 . Nonaqueous - Electrolyte Battery ] one or more of the hydrogen atoms bonded to the nitrogen Nonaqueous - electrolyte battery 4 of the invention atoms with a hydrocarbon group . includes : a negative electrode and a positive electrode which are capable of occluding and releasing ions; and the non - 30 The number of the nitrogen atoms constituting the ring is aqueous electrolyte 4 of the invention . preferably 3 or larger , especially preferably 4 or larger , and < 2 - 1 . Battery Constitution > is preferably 6 or smaller , especially preferably 4 or smaller. Nonaqueous -electrolyte secondary battery 4 of the inven The alkylene groups are not particularly limited . However , tion may have the same battery constitution as that described alkylene groups having 2 - 4 carbon atoms, such as ethylene , above with regard to nonaqueous - electrolyte secondary bat - 35 methylethylene , propylene, and butylene, are preferred . tery 1 . Especially preferred is ethylene or propylene . Two or more < 2 - 2 . Nonaqueous Electrolyte > kinds of alkylene groups may be contained . As the nonaqueous electrolyte , the nonaqueous electrolyte Examples of the hydrocarbon group with which the 4 of the invention described above is used . Incidentally , a hydrogen bonded to a nitrogen atom is replaced include mixture of nonaqueous electrolyte 4 of the invention and 40 alkyl groups, aryl groups, and aralkyl groups . Preferred of another nonaqueous electrolyte may be used so long as this these are alkyl groups . Examples of the alkyl groups include is not counter to the spirit of invention 4 . methyl , ethyl , propyl, isopropyl, and butyl. Examples of the < 2 - 3 . Negative Electrode > aryl groups include aryl groups having 6 - 8 carbon atoms, The negative electrode of nonaqueous - electrolyte second such as phenyl, p - tolyl, ethylphenyl, and dimethylphenyl. ary battery 4 may be the same as the negative electrode 45 Examples of the aralkyl groups include benzyl and phen described above with regard to nonaqueous - electrolyte sec ethyl. ondary battery 1 . The molecular weight of the cyclic polyamine compound < 2 - 4 . Positive Electrode > of invention 5 is preferably 120 or higher , more preferably The positive electrode of nonaqueous -electrolyte second - 170 or higher, and is preferably 800 or lower , more prefer ary battery 4 may be the same as the positive electrode 50 ably 400 or lower , especially preferably 300 or lower. When described above with regard to nonaqueous- electrolyte sec the molecular weight thereof exceeds the upper limit of that ondary battery 1 . range , there are cases where this polyamine compound is < 2 - 5 . Separator > reduced in compatibility with or solubility in the nonaque The separator of nonaqueous- electrolyte secondary bat ous electrolyte , resulting in a decrease in capacity especially tery 4 may be the same as the separator described above with 55 at low temperatures . regard to nonaqueous - electrolyte secondary battery 1 . Examples of the cyclic polyamine compound of invention < 2 - 6 . Battery Design > 5 are shown below . However , the cyclic polyamine com The battery design of nonaqueous - electrolyte secondary pound of invention 5 should not be construed as being battery 4 may be the same as the battery design described limited to the following examples. above with regard to nonaqueous -electrolyte secondary bat- 60 Examples of the cyclic polyamine compound of invention tery 1 . 5 include Nonaqueous - electrolyte secondary battery 5 of the inven - triazacycloalkanes such as 1 , 4 , 7 -triazacyclononane , 1 , 4 , 7 tion is constituted of a nonaqueous electrolyte and a positive triazacyclodecane , 1, 4 ,8 - triazacycloundecane , 1, 5 , 9- triaza electrode and a negative electrode which both are capable of cyclododecane , and 1 , 6 , 11 - triazacyclopentadecane etc . ; occluding and releasing lithium . Nonaqueous - electrolyte 65 tetraazacycloalkanes such as 1 , 4 , 7 , 10 - tetraazacyclodode secondary battery 5 of the invention may be equipped with cane (another name: cyclen ), 1 , 4 , 7 , 10 -tetraazacyclotride other constitutions. cane , 1 , 4, 7 , 11 - tetraazacyclotetradecane, 1, 4 ,8 ,11 - tetraaza US 9 ,853 , 326 B2 125 126 cyclotetradecane ( another name: cyclam ), 1 , 4 , 8 , 12 - undergo oxidation at the positive electrode . Upon this oxi tetraazacyclopentadecane , and 1, 5, 9, 13 - dation , the compounds form a stable coating film on the tetraazacyclohexadecane ; positive electrode . Because of this , the nonaqueous- electro pentaazacycloalkanes such as 1 , 4 , 7 , 10 , 13 -pentaazacyclo - lyte secondary battery employing the nonaqueous electro pentadecane and 1 , 4 ,7 , 10 , 13 -pentaazacyclohexadecane ; 5 lyte containing any of these cyclic polyamine compounds hexaazacycloalkanes such as 1 , 4 , 7 , 10 , 13 , 16 -hexaazacy - has improved continuous - charge characteristics . 16 -hexaazacyclononadecane nother name :etc hexacyclen .; ) and 1 , 4 , 7 , 10 , 13 , [ 1 - 2 . Composition ] hydrocarbon - group - substituted triazacycloalkanes such as The content of the cyclic polyamine compound of inven 1 ,4 , 7 - tetramethyl- 1, 4 ,7 - triazacyclononane , 2, 5 ,8 - tetram - 10 tion 5 is not particularly limited so long as the compound ethyl- 1 , 4 , 7 - triazacyclononane , 1 , 4 , 7 -tetraethyl - 1 , 4 , 7 - triaza dissolves in the nonaqueous solvent which will be described cyclononane , 1 , 4 , 7 - tetraphenyl- 1 , 4 , 7 -triazacyclononane , later. However, the cyclic polyamine compound is contained 1 , 4 , 7 -tetrabenzyl - 1 , 4 , 7 -triazacyclononane , 1 , 5 , 9 - tetram in such an amount that the content thereof is generally ethyl- 1, 5 , 9 - triazacyclododecane, 1 ,5 , 9- tetraethyl - 1, 5 ,9 - tri 0 . 001 % by mass or higher , preferably 0 .01 % by mass or azacyclododecane . 1. 5 . 9 -tetraphenyl - 1 . 5 . 9 - triazacyclodode - 15 higher, and is generally 5 % by mass or lower, preferably 1 % cane , and 1 , 5 , 9 -tetrabenzyl - 1 , 5 , 9 - triazacyclododecane etc . ; by mass or lower, especially preferably 0 . 2 % by mass or hydrocarbon - group - substituted tetraazacycloalkanes such as lower , based on the whole nonaqueous electrolyte . When the 1 , 4 , 7 ,10 - tetramethyl- 1 , 4 , 7 , 10 - tetraazacyclododecane , 2 , 5 , 8 , content thereof is lower than the lower limit of that range , 11 - tetramethyl- 1 , 4 , 7 , 10 - tetraazacyclododecane , 1 , 4 , 7 , 10 - te there are cases where the effects of invention are hardly tramethyl- 1 , 4 , 7 , 10 - tetraazacyclododecane , 1 , 4 , 7 , 10 - tetra - 20 produced . When the content thereof exceeds the upper limit , ethyl- 1 , 4 , 7 , 10 - tetraazacyclododecane , 1 , 4 , 7 , 10 - tetraphenyl there are cases where the nonaqueous organic solvent 1 , 4 , 7 ,10 - tetraazacyclododecane , 1 , 4 , 7 , 10 -tetrabenzyl - 1 , 4 , 7 , including carbonates comes to undergo a decomposition 10 -tetraazacyclododecane , 1 , 4 , 8 , 11 - tetramethyl- 1 , 4 , 8 , 11 - reaction catalyzed by the cyclic polyamine compound , tetraazacyclotetradecane , 1 , 4 , 8 , 11 - tetraethyl- 1 , 4 , 8 , 11 - resulting in a decrease in battery characteristics such as rate tetraazacyclotetradecane , 1 , 4 , 8 , 11 - tetraphenyl- 1 , 4 , 8 , 11 - 25 characteristics. In the case of using two or more cyclic tetraazacyclotetradecane , 1 , 4 , 8 , 11 - tetrabenzyl- 1 , 4 , 8 , 11 - polyamine compounds of invention 5 in combination , the tetraazacyclotetradecane , 1 , 4 , 8 , 12 -tetramethyl - 1 , 4 ,8 , 12 - cyclic polyamine compounds of invention 5 are used so that tetraazacyclopentadecane, 1 , 4 , 8 , 12 - tetraethyl- 1 , 4 , 8 ,12 the total concentration thereof is within the range shown tetraazacyclopentadecane , 1 , 4 , 8 , 12 - tetraphenyl- 1 , 4 ,8 , 12 - above . tetraazacyclopentadecane , and 1, 4 , 8, 12 - tetrabenzyl- 1 ,4 , 8, 30 [2 . Cyclic Polyamide Compound ] 12 - tetraazacyclopentadecane ; and [2 -1 . Kind ] hydrocarbon - group - substituted hexaazacycloalkanes such The cyclic polyamide compound which may be contained as 1 , 4 , 7 , 10 , 13 , 16 -hexamethyl - 1 , 4 , 7 , 10 , 13 , 16 -hexaazacy - in nonaqueous electrolyte 5 of the invention (hereinafter clooctadecane , 1 , 4 , 7 , 10 , 13 , 16 - hexaethyl- 1 , 4 , 7 , 10 , 13 , 16 suitably referred to as " cyclic polyamide compound of hexaazacyclooctadecane , 1 , 4 , 7 , 10 , 13 , 16 -hexaphenyl - 1 , 4 , 7 , 35 invention 5 " ) is a compound having two or more amide 10 ,13 , 16 -hexaazacyclooctadecane , and 1 , 4 , 7 , 10 , 13 , 16 - bonds ( NHCO ) in the ring framework . The number of hexabenzyl- 1 ,4 , 7 , 10 , 13, 16 - hexaazacyclooctadecane , and the amide bonds constituting the ring is preferably 2 or the like . larger and is preferably 6 or smaller, especially preferably 4 Preferred of these are or smaller . A cyclic polyamide compound having two amide triazacycloalkanes such as 1 , 4 , 7 -triazacyclononane and 1 , 5 , 40 bonds can be synthesized, for example , by the reaction of an 9 - triazacyclododecane ; tetraazacycloalkanes such as 1 , 4 , 7 , acyclic polyamine compound with a malonic acid deriva 10 -tetraazacyclododecane ( another name: cyclen ) , 1 , 4 , 8 , 11 - tive . Cyclic polyamide compounds having three or more tetraazacyclotetradecane ( another name: cyclam ), and 1 , 4 , amide bonds can be synthesized , for example , by the cycl 8 ,12 - tetraazacyclopentadecane ; and ization polymerization reaction of various amino acids . 1 , 4 , 7 , 10 , 13 , 16 -hexaazacyclooctadecane ( another name: 45 The molecular weight of the cyclic polyamide compound hexacyclen ) and methyl- substituted azacycloalkanes such as of invention 5 is preferably 160 or higher , more preferably 1 ,4 ,7 - tetramethyl- 1 , 4, 7 - triazacyclononane , 1, 5 ,9 - tetram - 200 or higher , and is preferably 800 or lower, more prefer ethyl- 1 , 5 , 9 - triazacyclododecane, 1 , 4 , 7 , 10 - tetramethyl- 1 , 4 , 7 , ably 600 or lower, especially preferably 500 or lower. When 10 - tetraazacyclododecane , 1 , 4 , 7 , 10 - tetramethyl - 1 , 4 , 7 , 10 - the molecular weight thereof exceeds the upper limit of that tetraazacyclododecane , 1 , 4 , 8 , 11 - tetramethyl- 1 , 4 , 8 , 11 - 50 range, there are cases where the cyclic polyamide compound tetraazacyclotetradecane , and 1 , 4 , 8 , 12 -tetramethyl - 1 , 4 , 8 , 12 - of invention 5 is reduced in compatibility with or solubility tetraazacyclopentadecane , and the like . in nonaqueous organic solvents and this may cause a Especially preferred of these are decrease in capacity especially at low temperatures . triazacycloalkanes such as 1 , 4 , 7 - triazacyclononane and 1 , 5 , Examples of the cyclic polyamide compound of invention 9 -triazacyclododecane ; tetraazacycloalkanes such as 1 , 4 ,7 , 55 5 are shown below . However, the cyclic polyamide com 10 - tetraazacyclododecane ( another name: cyclen ) , 1, 4 , 8 , 11 pound of invention 5 should not be construed as being tetraazacyclotetradecane (another name: cyclam ) , and 1 , 4 , limited to the following examples. 8 , 12 - tetraazacyclopentadecane ; and Examples of the cyclic polyamide compound of invention methyl- substituted tetraazacycloalkanes such as 1 , 4 , 8 , 11 - 5 which has two amide bonds include tetramethyl- 1 , 4 , 8 , 11 -tetraazacyclotetradecane , and the like . 60 (substituted ) triazacycloalkanediones such as 1 , 4 , 7 - triazacy One cyclic polyamine compound of invention 5 may be clodecane - 8 , 10 - dione , 9 -methyl - 1 , 4 , 7 - triazacyclodecane - 8 , used alone, or any desired combination of two or more 10 - dione , 9 , 9 '- dimethyl- 1 , 4 , 7 - triazacyclodecane - 8 , 10 - di cyclic polyamine compounds of invention 5 in any desired one, 9 - ethyl- 1 , 4 , 7 - triazacyclodecane- 8 ,10 - dione, 9 - phenyl proportion may be used . 1 ,4 , 7 - triazacyclodecane- 8 , 10 -dione , 9 -benzyl - 1 , 4 ,7 These cyclic polyamine compounds have a molecular 65 triazacyclodecane - 8 , 10 - dione , 1 , 5 , 9 - triazacyclododecane - 6 , weight which is not excessively high . These compounds 8 - dione, 7 -methyl - 1, 5 , 9 - triazacyclododecane -6 , 8 -dione , readily dissolve in nonaqueous organic solvents and partly 7 ,7 ' -methyl - 1, 5 ,9 - triazacyclododecane - 6 ,8 - dione, 7 -ethyl - 1, US 9 ,853 , 326 B2 127 128 5 , 9 -triazacyclododecane -6 ,8 -dione , 7 -phenyl - 1 , 5 , 9 - triaza [ 2 - 2 . Composition ] cyclododecane -6 , 8 - dione, and 7 -benzyl - 1 , 5 , 9 - triazacy - The content of the cyclic polyamide compound of inven clododecane - 6 , 8 - dione ; tion 5 is not particularly limited so long as the compound ( substituted ) tetraazacycloalkanediones such as 1 . 4 . 7 .10 - dissolves in the nonaqueous solvent which will be described tetraazacyclotridecane -11 ,13 -dione , 12 -methyl - 1 , 4 , 7 , 10 - tet - 5 later . However, the cyclic polyamide compound is contained raazacyclotridecane- 11, 13 - dione, 12, 12' - dimethyl - 1 , 4 , 7 , 10 in such an amount that the content thereof is generally tetraazacyclotridecane - 11 , 13 - dione , 12 -ethyl - 1 , 4 , 7 , 10 0 . 001 % by mass or higher , preferably 0 .01 % by mass or higher , and is generally 5 % by mass or lower, preferably 1 % tetraazacyclotridecane - 11, 13 - dione , 12 - phenyl- 1 , 4 , 7 , 10 by mass or lower , especially preferably 0 .2 % by mass or tetraazacyclotridecane - 11, 13 -dione , 12 -benzyl - 1, 4 ,7 ,10 1. 10 lower, based on the whole nonaqueous electrolyte . When the tetraazacyclotridecane - 11, 13 - dione , 1 , 4 , 8 , 11 content thereof is lower than the lower limit of that range , tetraazacyclotetradecane - 5 , 7 - dione , 6 -methyl - 1 , 4 , 8 , 11 there are cases where the effects of invention 5 are hardly tetraazacyclotetradecane - 5 ,7 -dione , 6 , 6 '- dimethyl - 1, 4 ,8 ,11 produced . When the content thereof exceeds the upper limit , tetraazacyclotetradecane - 5 , 7 - dione, 6 -ethyl - 1 , 4 , 8 , 11 there are cases where the coating film formed on the positive tetraazacyclotetradecane - 5 , 7 - dione , 6o - phenyl- 1 , 4 ,8 8 ,, 11 15 electrode has an increased thickness and higher resistance tetraazacyclotetradecane - 5 , 7 -dione , 6 -benzyl - 1 , 4 ,8 ,11 and this coating film hence inhibits the movement of lithium tetraazacyclotetradecane - 5 , 7 - dione , 1 , 4 , 8 , 12 (Li ) ions , resulting in a decrease in battery characteristics tetraazacyclopentadecane - 9 , 11- dione , 10 -methyl - 1 , 4 , 8 , 12 such as rate characteristics . In the case of using two or more tetraazacyclopentadecane - 9 , 11 -dione , 10 , 10 ' - dimethyl - 1 , 4 , cyclic polyamide compounds of invention 5 in combination , 8 ,12 -tetraazacyclopentadecane - 9 , 11 -dione , 10 - ethyl- 1 , 4 , 8 , 20 the cyclic polyamide compounds of invention 5 are used so 12 - tetraazacyclopentadecane - 9 , 11 -dione , 10 -phenyl - 1 , 4 , 8 , that the total concentration thereof is within the range shown 12 -tetraazacyclopentadecane - 9 , 11 - dione , and 10 - benzyl - 1 , above. 4 , 8 , 12 - tetraazacyclopentadecane - 9 , 11 -dione ; and [ 3 . At Least One Compound Selected from Group Consist ( substituted ) tetraazacycloalkanediones such as 1 , 4 , 7 , 10 , 13 , ing of Unsaturated Carbonates , Fluorine - Containing Car 16 - hexaazacyclononadecane - 17 , 19 -dione , 18 -methyl - 1 , 4 , 7 , 25 bonates , Monofluorophosphates, and Difluorophosphates ] 10 , 13 , 16 -hexaazacyclononadecane - 17 , 19 - dione, 18 , 18 - Nonaqueous electrolyte 5 of the invention further contains ethyl- 1, 4 ,7 , 10 , 13 , 16 -hexaazacyclononadecane - 17, 19 - dione, at least one compound selected from the group consisting of unsaturated carbonates, fluorine -containing carbonates , 18 -ethyl - 1, 4 ,7 ,10 , 13 ,16 - hexaazacyclononadecane - 17 ,19 -di monofluorophosphates , and difluorophosphates . These com one, 18 -phenyl - 1 ,4 , 7 ,10 , 13, 16 -hexaazacyclononadecane - 30 pounds are incorporated , for example , for the purpose of 17 , 19 - dione, and 18 -benzyl - 1 , 4 , 7 , 10 , 13, 16 -hexaazacy forming a coating film on the negative electrode to improve clononadecane - 17, 19 - dione, and the like . battery characteristics . Examples of the cyclic polyamide compound which has [3 - 1 . Kind ] three or more amide bonds include The unsaturated carbonates are not particularly limited so cyclic triamides such as cyclo (- glycyl) 3 , cyclo (ß -alanyl ) 3 , 35 long as they are carbonates having one or more carbon and cyclo (- proly1) 3 ; carbon unsaturated bonds. Any desired unsaturated carbon cyclic tetraamides such as cyclo ( - glycyl) 4 , cyclo ( ß - alanyl ) 4 , ates can be used . Examples thereof include carbonates cyclo ( ß - alanylglycyl- ß -alanylglycyl ) , cyclo ( ß -alanylprolyl having one or more aromatic rings and carbonates having B - alanylprolyl ), cyclo ( - glycyl) 4 , and cyclo ( ß - alanyl) 4 ; and one or more carbon - carbon unsaturated bonds such as car cyclic hexaamides such as cyclo (- glycyl )6 and cyclo ( -pro - 40 bon - carbon double bonds or carbon -carbon triple bonds. The lyl - glycyl ) 3 , and the like . unsaturated carbonates are the same as those described Preferred of these are above with regard to nonaqueous electrolyte 1 . triazacycloalkanediones such as 1 , 4 , 7 - triazacyclodecane - 8 , The fluorine - containing carbonates are not limited so long 10 -dione and 1 , 5 , 9 - triazacyclododecane- 6 , 8 -dione ; tetraaza as they are carbonates having a fluorine atom . Any desired cycloalkanediones such as 1 , 4 , 7 , 10 - tetraazacyclotridecane - 45 fluorine -containing carbonates can be used . 11 , 13 - dione , 1 , 4 , 8 , 11 - tetraazacyclotetradecane - 5 , 7 -dione , Examples thereof include and 1, 4 ,8 ,12 -tetraazacyclopentadecane - 9 , 11- dione ; hexa - fluorine -containing cyclic carbonates such as fluoroethylene amides such as cyclo (ß -alanylglycyl - ß -alanylglycyl ) and carbonate, 1 , 1 -difluoroethylene carbonate, cis - difluoroeth cyclo ( -prolyl - glycyl) 3 ; and the like . ylene carbonate , trans -difluoroethylene carbonate, fluoro Especially preferred of these are 50 propylene carbonate , and trifluoromethylethylene carbonate ; 1 , 4 ,7 , 10 - tetraazacyclotridecane - 11, 13 -dione , 1, 4 , 8 ,11 - tet and raazacyclotetradecane - 5 , 7 -dione , 1 , 4 , 8 , 12 - tetraazacyclo fluorine - containing acyclic carbonates such as trifluorom pentadecane - 9 , 11 -dione , cyclo (ß -alanylglycyl - ß - alanylgly ethyl methyl carbonate , trifluoromethyl ethyl carbonate , cyl) , and the like . 2 - fluoroethyl methyl carbonate , 2 - fluoroethyl ethyl carbon One of the polyamide compounds of invention 5 shown 55 ate, 2 , 2 , 2 - trifluoroethyl methyl carbonate , 2 , 2 , 2 - trifluoro above may be used alone , or any desired combination of two ethyl ethyl carbonate , bis ( trifluoromethyl) carbonate, bis ( 2 or more thereof in any desired proportion may be used . fluoroethyl) carbonate , and bis ( 2 , 2 , 2 - trifluoroethyl) These cyclic polyamide compounds of invention 5 have a carbonate , and the like . molecular weight which is not excessively high . These compounds readily dissolve in nonaqueous organic solvents 60 fluorine - containing cyclic carbonates such as fluoroethylene and partly undergo oxidation at the positive electrode . Upon carbonate , cis - difluoroethylene carbonate , and trans - difluo this oxidation , the compounds form a stable coating film on roethylene carbonate are preferred because these carbonates the positive electrode . Because of this , the nonaqueous form a stable interface - protective coating film on the nega electrolyte secondary battery employing the nonaqueous tive electrode . electrolyte containing any of these cyclic polyamide com - 65 One fluorine -containing carbonate may be used alone, or pounds of invention 5 has improved continuous - charge any desired combination of two or more fluorine -containing characteristics . carbonates in any desired proportion may be used . US 9 ,853 , 326 B2 129 130 As the monofluorophosphates and difluorophosphates, sequently , the continuous- charge characteristics of the non any desired ones can be used . With respect to the “ mono aqueous- electrolyte secondary battery can be greatly height fluorophosphates and difluorophosphates ” to be used in ened . invention 5 (including all of embodiment 5 - 1 , embodiment [4 . Nonaqueous Organic Solvent] 5 - 2 , and embodiment 5 - 3 ), the kinds and contents thereof, 5 The nonaqueous organic solvent is not particularly lim places where the salts exist, methods of analysis , production ited , and known nonaqueous organic solvents can be used at process, etc ., are the same as those described above with will so long as the electrolyte which will be described later regard to nonaqueous electrolyte 1 . Especially preferred can dissolve therein . Examples thereof include acyclic car examples thereof include lithium monofluorophosphate , bonates , cyclic carbonates, acyclic esters, cyclic esters ( lac sodium monofluorophosphate , potassium monofluorophos - tone compounds ) , acyclic ethers, cyclic ethers , and sulfur phate , lithium difluorophosphate , sodium difluorophosphate , containing organic solvents . Preferred of these are acyclic and potassium difluorophosphate . Preferred of these are carbonates , cyclic carbonates, acyclic esters , cyclic esters , lithium monofluorophosphate and lithium difluorophos - acyclic ethers , or cyclic ethers as solvents having high ionic phate . One monofluorophosphate or difluorophosphate may 15 conductivity . These solvents are the same as those described be used alone , or any desired combination of two or more of above with regard to nonaqueous electrolytes 1 to 4 . How monofluorophosphates and difluorophosphates in any ever , the following are preferred . desired proportion may be used . Examples of the acyclic carbonates include dimethyl [ 3 - 2 . Composition ] carbonate , diethyl carbonate , ethylmethyl carbonate , methyl The concentration of the at least one compound selected 20 propyl carbonate , and ethyl propyl carbonate . from the group consisting of unsaturated carbonates , fluo Examples of the cyclic carbonates include ethylene car rine- containing carbonates, monofluorophosphates, and dif - bonate , propylene carbonate , butylene carbonate , fluoroeth luorophosphates in nonaqueous electrolyte 5 is generally ylene carbonate, difluoroethylene carbonate , fluoropropyl 0 .01 % by mass or higher, preferably 0 . 1 % by mass or higher, ene carbonate , and trifluoromethylethylene carbonate . more preferably 0 . 3 % by mass or higher, and is generally 25 Examples of the acyclic ethers include 1 , 2 -dimethoxy 10 % by mass or lower, preferably 7 % by mass or lower , ethane , 1 , 2 -diethoxyethane , and diethyl ether. more preferably 5 % by mass or lower , based on the whole Examples of the cyclic ethers include tetrahydrofuran , nonaqueous electrolyte . In case where the concentration 2 -methyltetrahydrofuran , 1 ,3 -dioxolane , and 4 -methyl - 1 ,3 dioxolane . thereof is too high , the coating film formed on the negative 30 Examples of the acyclic esters include methyl formate , electrode has an increased thickness and higher resistance, 30 methyl acetate, and methyl propionate . resulting in a decrease in battery capacity . There also are Examples of the cyclic esters include y -butyrolactone and cases where gas evolution is enhanced under high - tempera y -valerolactone . ture conditions and this further increases resistance to reduce One nonaqueous organic solvent may be used alone , or the capacity . When the concentration thereof is too lowY ,; 35 any desired combination of two ormore nonaqueous organic there are cases where the effects of invention 5 are not solvents in any desired proportion may be used . However , it sufficiently produced . is preferred to use a mixture of two or more nonaqueous [ Function ] organic solvents in order to impart the desired characteris Reasons for the preference of the containment of at least tics , i . e . . continuous -charge characteristics . In particular, it is one compound selected from the group consisting of unsatu - 40 preferred that the mixture should consist mainly of at least rated carbonates , fluorine -containing carbonates, monofluo - one cyclic carbonate and (at least one acyclic carbonate or rophosphates, and difluorophosphates in nonaqueous elec - at least one cyclic ester ). The term “ consist mainly of” as trolyte 5 of the invention are explained here . However, used here means that the nonaqueous organic solvents invention 5 should not be construed as being limited by the include at least one cyclic carbonate and (at least one acyclic following reasons . The polyamine compound and /or poly - 45 carbonate or at least one cyclic ester ) in a total amount of amide compound of invention 5 is oxidized at the positive 70 % by mass or larger based on the whole nonaqueous electrode at a less noble potential than the solvent and electrolyte . functions as a positive -electrode -protective coating film . In the case where two or more nonaqueous organic This protective coating film inhibits the solvent from sub - solvents are used in combination , examples of preferred sequently undergoing an oxidation reaction . The perfor - 50 combinations include : binary solvents such as ethylene mance deterioration of, in particular , high - voltage batteries carbonate/ methyl ethyl carbonate , ethylene carbonate / di can hence be mitigated . However, there are cases where ethyl carbonate , and ethylene carbonate / y -butyrolactone ; these compounds are reduced at the negative electrode to and ternary solvents such as ethylene carbonate /dimethyl form a high -resistance coating film and this adversely influ - carbonate / ethyl methyl carbonate and ethylene carbonatel ences battery characteristics including high - load character- 55 methyl ethyl carbonate/ diethyl carbonate. Nonaqueous istics . When at least one compound selected from the group organic solvents mainly including these compounds are consisting of unsaturated carbonates, fluorine - containing suitable because they attain a satisfactory balance among carbonates , monofluorophosphates , and difluorophosphates various properties . coexists in the electrolyte , these compounds are reduced at In the case where an organic solvent is used as the the negative electrode at a nobler potential than the 60 nonaqueous organic solvent, the number of carbon atoms of polyamine compound and / or polyamide compound to form the organic solvent is generally 3 or larger and is generally a protective coating film and thereby inhibit the polyamine 13 or smaller, preferably 7 or smaller . When the number of compound and /or polyamide compound from reacting at the carbon atoms thereof is too large , there are cases where this negative electrode . As a result, no high - resistance coating organic solvent shows poor infiltration into the separator and film is formed on the negative electrode, and a stable coating 65 negative electrode, making it impossible to attain sufficient film is formed on the positive electrode to inhibit the capacity . On the other hand , when the number of carbon electrolyte from reacting with the positive electrode. Con atoms thereof is too small , there are cases where this organic US 9 ,853 , 326 B2 131 132 solvent has enhanced volatility to form a cause of an [6 . Other Aids ] increase in the internal pressure of the battery . “ Other aids ” may be incorporated into nonaqueous elec The molecular weight of the nonaqueous organic solvent trolyte 5 of the invention for the purpose of improving the is generally 50 or higher, preferably 80 or higher, and is wetting properties of the nonaqueous electrolyte , overcharge 5 characteristics , etc ., unless the effects of invention 5 are generally 250 or lower , preferably 150 or lower. When the 5 charalessened thereby . Examples of the “ other aids” include : acid molecular weight thereof is too high , there are cases where anhydrides such as maleic anhydride , succinic anhydride , this nonaqueous organic solvent shows poor infiltration into and glutaric anhydride; carboxylic acid esters such as vinyl the separator and negative electrode, making it impossible to acetate , divinyl adipate , and allyl acetate ; sulfur - containing attain sufficient capacity . On the other hand , when the compounds such as diphenyl disulfide, 1, 3 -propanesultone , molecular weight thereof is too low , there are cases where 0 1, 4 - butanesultone , dimethyl sulfone , divinyl sulfone , dim this nonaqueous organic solvent has enhanced volatility to ethyl sulfite , ethylene sulfite, 1 , 4 -butanediol dimethanesul form a cause of an increase in the internal pressure of the fonate , methylmethanesulfonate , and 2 -propynyl methane battery . sulfonate ; and aromatic compounds such as t - butylbenzene , biphenyl, o - terphenyl, 4 - fluorobiphenyl, fluorobenzene , 2 , 4 Furthermore , in the case where two or more nonaqueous 15 difluorobenzene , cyclohexylbenzene , diphenyl ether, 2 , 4 organic solvents are used in combination , the proportion of difluoroanisole , and trifluoromethylbenzene and these aro a cyclic carbonate in the nonaqueous organic solvents is matic compounds substituted with a fluorine atom . One of generally 5 % by mass or higher, preferably 10 % by mass or such “ other aids ” may be used alone , or any desired com higher, more preferably 15 % by mass or higher, especially bination of two or more thereof in any desired proportion preferably 20 % by mass or higher , and is generally 60 % by 20 may be used . mass or lower , preferably 50 % by mass or lower, especially The concentration of the “ other aids” in the nonaqueous preferably 40 % by mass or lower , based on the whole electrolyte is generally 0 .01 % by mass or higher , preferably nonaqueous organic solvents . When the proportion thereof is 0 .05 % by mass or higher , and is generally 10 % by mass or lower than the lower limit of that range, lithium salt disso - lower, preferably 5 % by mass or lower, based on the whole ciation is less apt to occur and electrical conductivity 25 nonaqueous electrolyte . In the case of using two or more of decreases . Consequently , high - load capacity is apt to the “ other aids ” in combination , these ingredients are used decrease . On the other hand , when the proportion thereof so that the total concentration thereof is within the range exceeds the upper limit , this electrolyte has too high a shown above. viscosity and lithium ions are less apt to move . There are [ 7 . State of Nonaqueous Electrolyte ] hence cases where high -load capacity decreases. 30 Nonaqueous electrolyte 5 is present usually in a liquid [ 5 . Lithium Salt ] state . However, this electrolyte may be caused to gel with a The lithium salt to be used as an electrolyte may be any polymer to obtain a semi- solid electrolyte . For the gelation , of inorganic lithium salts and organic lithium salts . any desired polymer may be used . Examples of the polymer Examples thereof include the same “ lithium salts ” as those include poly ( vinylidene fluoride ) , copolymers of poly ( vi enumerated above under “ Electrolyte ” with regard to non - 35 nylidene fluoride ) and hexafluoropropylene, poly ( ethylene aqueous electrolyte 1 . Examples of the inorganic lithium oxide ), polyacrylates, and polymethacrylates . One polymer salts include: inorganic fluoride salts such as LiPF , LiAsF6 , may be used alone for the gelation , or any desired combi LiBF4, and LiSbF6; inorganic chloride salts such as LiAlCl4 ; nation of two or more polymers in any desired proportion and perhalogen acid salts such as LiCiO . , LiBrod, and may be used for the gelation . LilO4. Examples of the organic lithium salts include fluo - 40 In the case where nonaqueous electrolyte 5 is used in the rine - containing organic lithium salts such as : perfluoroal form of a semi-solid electrolyte , the proportion of the kanesulfonic acid salts , e . g . , CF2S0zL1 and C4F , S02Li; nonaqueous electrolyte to the semi- solid electrolyte is gen perfluoroalkanecarboxylic acid salts , e . g . , CF3COOLi; per erally 30 % by mass or higher , preferably 50 % by mass or fluoroalkanecarbonimide salts , e . g ., (CF3CO ) 2NLi; and per - higher , especially preferably 75 % by mass or higher, and is fluoroalkanesulfonimide salts , e . g . , ( CF2SO2) NLi and 45 generally 99 .95 % by mass or lower , preferably 99 % by mass (C2F S02) NLi, and the like . or lower, especially preferably 98 % by mass or lower, based Of these , LiPF , LiBF , CF SO , Li, (CF280 , ) ,NLi , and on the total amount of the semi- solid electrolyte . When the the like are preferred because these salts are apt to dissolve proportion of the nonaqueous electrolyte is too high , there in solvents and have a high degree of dissociation . One are cases where it is difficult to retain the electrolyte and electrolyte may be used alone , or any desired combination of 50 liquid leakage is apt to occur. Conversely , when the propor two or more electrolytes in any desired proportion may be tion thereof is too low , there are cases where this electrolyte used . In particular , a combination of LiPF6 and LiEF4 or a is insufficient in charge/ discharge efficiency and capacity. combination of LiPF and (CF2SO2 ) 2NLi is preferred [ 8 . Process for Producing Nonaqueous Electrolyte ] because these combinations are effective in improving con Nonaqueous electrolyte 5 of the invention can be prepared tinuous - charge characteristics . 55 by dissolving a lithium salt , the cyclic polyamine compound The concentration of the electrolyte in the nonaqueous and /or cyclic polyamide compound according to invention electrolyte is generally 0 . 5 mol/ L or higher, preferably 0 .75 5 , and “ at least one compound selected from the group mol/ L or higher, and is generally 2 mol /L or lower, prefer consisting of unsaturated carbonates , fluorine - containing ably 1 .75 mol / L or lower, based on the nonaqueous electro - carbonates, monofluorophosphates , and difluorophosphates” lyte . When the concentration thereof is too low , there are 60 in a nonaqueous organic solvent optionally together with cases where this nonaqueous electrolyte has an insufficient “ other aids” . electrical conductivity . On the other hand , in case where the It is preferred that in preparing nonaqueous electrolyte 5 , concentration thereof is too high , this nonaqueous electro - each of the raw materials for the nonaqueous electrolyte , i . e . , lyte has an increased viscosity and , hence , a reduced elec - the lithium salt, cyclic polyamine compound and/ or cyclic trical conductivity and is apt to suffer deposition at low 65 polyamide compound according to invention 5 , nonaqueous temperatures. There is hence a tendency that the nonaque - organic solvent , and “ other aids ” , should be dehydrated ous - electrolyte secondary battery has reduced performances . beforehand. With respect to the degree of dehydration , it is US 9 ,853 , 326 B2 133 134 desirable to dehydrate each raw material to generally 50 amount during high - temperature continuous charge, result ppm or lower, preferably 30 ppm or lower. In this descrip - ing in an increase in resistance and a decrease in recovery tion , ppm means proportion by weight. capacity . When water is present in the nonaqueous electrolyte , The number of carbon atoms of the cyclic carbonate is there are cases where electrolysis of the water, reaction of 5 generally 3 or larger and is generally 13 or smaller , prefer the water with lithium metal, hydrolysis of the lithium salt, ably 5 or smaller . When the number of carbon atoms thereof etc . occur. Techniques for the dehydration are not particu - is too large , there are cases where this cyclic carbonate larly limited . However, in the case where the material to be shows poor infiltration into the separator and negative dehydrated is , for example , a liquid , e . g ., a nonaqueous electrode , making it impossible to attain sufficient capacity . organic solvent, a molecular sieve or the like may be used . " On the other hand , when the number of carbon atoms thereof In the case where the material to be dehydrated is a solid , is too small , there are cases where this cyclic carbonate has e . g ., a lithium salt , this material may be dried at a tempera enhanced volatility to form a cause of an increase in the ture lower than decomposition temperatures. internal pressure of the battery . 15 [ 3 . Nonaqueous Organic Solvent ] Embodiment 5 - 2 The nonaqueous organic solvent is as described above . [ 4 . Lithium Salt ] Another essential point of invention 5 resides in a non - The lithium salt is as described above . aqueous electrolyte which includes a nonaqueous organic [ 5 . At Least One Compound Selected from Group Consist solvent and a lithium salt dissolved therein , and is charac - 20 ing of Unsaturated Carbonates , Fluorine -Containing Car terized in that the nonaqueous organic solvent contains a bonates , Monofluorophosphates , and Difluorophosphates ] cyclic polyamine compound and further contains at least one In embodiment 5 - 2 also , it is preferred to incorporate at cyclic carbonate in an amount of from 5 % by mass to 40 % least one compound selected from the group consisting of by mass based on the whole nonaqueous organic solvent. unsaturated carbonates , fluorine - containing carbonates , This electrolyte is referred to as " embodiment 5 - 2 ” . 25 monofluorophosphates, and difluorophosphates. These com [ 1 . Cyclic Polyamine Compound ] pounds are as described above . [ 1 - 1. Kind ] The kind of the cyclic polyamine compound is as [ 6 . Other Aids ] described above. Other aids are as described above . [ 1 - 2 . Composition ] [ 7 . State of Nonaqueous Electrolyte ] The composition is as described above . 30 The state of the nonaqueous electrolyte is as described [ 2 . Cyclic Carbonate ] above. The cyclic carbonate in invention 5 is not particularly [ 8 . Process for Producing Nonaqueous Electrolyte ] limited so long as it is a cyclic carbonate . Part or all of the The process is as described above . hydrogen atoms may have been replaced with a halogen , 35 e . g ., fluorine or chlorine . Examples thereof include ethylene Embodiment 5 - 3 carbonate , propylene carbonate , butylene carbonate , fluoro ethylene carbonate , difluoroethylene carbonate , fluoropro Still another essential point of invention 5 resides in a pylene carbonate , and trifluoromethylethylene carbonate . nonaqueous electrolyte which includes a nonaqueous One of such cyclic carbonates may be used alone, or any 40 organic solvent and a lithium salt dissolved therein , and is desired combination of two or more there in any desired characterized by containing a cyclic polyamide compound . proportion may be used . This electrolyte is referred to as " embodiment 5 -3 ” . Especially preferred are: a combination of ethylene car - [ 1 . Cyclic Polyamide Compound ] bonate and propylene carbonate ; a combination of ethylene [ 1 - 1 . Kind ] carbonate and fluoroethylene carbonate ; and a combination 45 The kind of the cyclic polyamide compound is as of ethylene carbonate , propylene carbonate , and fluoroeth - described above. ylene carbonate . [ 1 - 2 . Composition ] Invention 5 is characterized in that the nonaqueous The composition is as described above . organic solvent contains a cyclic carbonate in an amount of [ 2 . Nonaqueous Organic Solvent] 5 - 40 % by mass based on the whole nonaqueous organic 50 Usable nonaqueous solvents are as described above . solvent. The lower limit of the content thereof is preferably The reason why a cyclic polyamide compound , even 8 % by mass or higher, especially preferably 10 % by mass or when used alone , enables the effects of this invention to be higher, more preferably 12 % by mass or higher . The upper produced is as follows. In a cyclic polyamide compound , the limit thereof is preferably 35 % by mass or lower, especially unshared electron pairs on the respective nitrogen atoms are preferably 30 % by mass or lower, more preferably 25 % by 55 in a delocalized state due to the influence of the adjoining mass or lower. Two or more cyclic carbonates may be used carbonyl groups. Cyclic polyamide compounds hence have in combination so long as the total amount thereof is within far lower basicity than cyclic polyamine compounds. the range shown above . Because of this, even when a solvent such as a cyclic In case where the proportion of the cyclic carbonate is carbonate is used in a large amount, this solvent is less apt lower than the lower limit of that range , lithium salt disso - 60 to react on the negative electrode . Consequently , the kinds of ciation is apt to occur and electrical conductivity hence the solvents to be used and the composition thereof are not decreases. Consequently , high - load capacity is apt to particularly limited . decrease. In case where the proportion thereof exceeds the [ 3 . Lithium Salt] upper limit , the nonaqueous organic solvent including the The lithium salt is as described above . cyclic carbonate comes to undergo a decomposition reaction 65 [ 4 . Cyclic Carbonate ] catalyzed by the polyamine compound . There are hence In embodiment 5 - 3 also , it is preferred to incorporate a cases where a gas, e. g. , carbon dioxide , generates in a large cyclic carbonate . The cyclic carbonate is as described above . US 9 ,853 , 326 B2 135 136 [ 5 . At Least One Compound Selected from Group Consist Nonaqueous electrolyte 6 of the invention includes a ing of Unsaturated Carbonates , Fluorine -Containing Car - nonaqueous solvent and an electrolyte dissolved therein , and bonates, Monofluorophosphates, and Difluorophosphates this nonaqueous electrolyte 6 contains “ at least one cyclic In embodiment 5 -3 also , it is preferred to incorporate at disulfonylimide salt represented by general formula ( 1 ) " and least one compound selected from the group consisting of 5 a monofluorophosphate and / or a difluorophosphate ” . unsaturated carbonates , fluorine - containing carbonates , monofluorophosphates , and difluorophosphates. These com pounds are as described above . [Chemical Formula- 7 ] [6 . Other Aids ] Other aids are as described above . 10 17 . State of Nonaqueous Electrolyte ] The state of the nonaqueous electrolyte is as described N - MnMn+ above . [ 8 . Process for Producing Nonaqueous Electrolyte ] The process is as described above . 1515 l II . Nonaqueous- Electrolyte Secondary Battery [ In the formula , R represents an alkylene group which has 1 - 12 carbon atoms and may be substituted with an alkyl Nonaqueous - electrolyte secondary battery 5 of the inven group , provided that the alkyl group ( s ) and the alkylene tion includes : a negative electrode and a positive electrode 20 groupgroup , maypr be substituted with a fluorine atom ; n is an which are capable of occluding/ releasing ions ; and the integer of 1 to 3 ; and M is one ormore metals selected from nonaqueous electrolyte of this invention . Group 1 , Group 2 , and Group 13 of the periodic table or a < 2 - 1 . Battery Constitution > quaternary onium .] Nonaqueous - electrolyte secondary battery 5 of the inven < 1 - 2 . Cyclic Disulfonylimide Salt Represented by General tion may have the same battery constitution as that described 25 Formula ( 1 ) above with regard to nonaqueous- electrolyte secondary bat In the cyclic disulfonylimide salt represented by general tery 1 . formula ( 1 ) , R represents an alkylene group which has 1 - 12 , < 2 - 2 . Nonaqueous Electrolyte > preferably 2 - 8 carbon atoms and which may be substituted As the nonaqueous electrolyte , the nonaqueous electrolyte with an alkyl group . The alkyl groups and the alkylene group 5 of the invention described above is used . Incidentally , a 30 may have been further substituted with a fluorine atom . mixture of nonaqueous electrolyte 5 of the invention and When the number of carbon atoms thereof is too large , this another nonaqueous electrolyte may be used so long as this disulfonylimide salt has an increased molecular weight per is not counter to the spirit of invention 5 . molecule and there are hence cases where the expected effect < 2 - 3 . Negative Electrode > is lessened . The negative electrode of nonaqueous- electrolyte second - 35 Examples of the unsubstituted alkylene group having ary battery 5 may be the same as the negative electrode 1 - 12 carbon atoms include ethylene , trimethylene , tetram described above with regard to nonaqueous -electrolyte sec ethylene, and pentamethylene. Examples of the alkyl groups ondary battery 1 . which may be introduced as substituents include linear or < 2 - 4 . Positive Electrode > branched alkyl groups having preferably 1 - 8 , especially The positive electrode of nonaqueous- electrolyte second - 40 preferably 1- 4 carbon atoms. These groups may have been ary battery 5 may be the same as the positive electrode further substituted with a fluorine atom . Examples of the described above with regard to nonaqueous- electrolyte sec - alkylene group substituted with an alkyl group include ondary battery 1 . propylene, 2 -methyltrimethylene , and neopentylene . < 2 - 5 . Separator> Any desired number of fluorine atoms can be introduced The separator of nonaqueous - electrolyte secondary bat - 45 into any desired sites in such an unsubstituted alkylene tery 5 may be the sameas the separator described above with group or alkyl- substituted alkylene group . Of such fluori regard to nonaqueous - electrolyte secondary battery 1. nated alkylene groups , perfluoroalkylene groups are pre < 2 - 6 . Battery Design > ferred from the standpoints of industrial availability , ease of The battery design of nonaqueous -electrolyte secondary production , etc . For example , perfluoroethylene and perfluo battery 5 may be the same as the battery design described 50 rotrimethylene are especially preferred . above with regard to nonaqueous -electrolyte secondary bat - In the cyclic disulfonylimide salt represented by general tery 1 . formula ( 1 ) , M is one or more metals selected from Group [ 1. Nonaqueous Electrolyte 6 ] 1 , Group 2 , and Group 13 of the periodic table (hereinafter Like ordinary nonaqueous electrolytes , nonaqueous elec - sometimes referred to as “ specific metals ” ) or a quaternary trolyte 6 of the invention includes an electrolyte and a 55 onium . nonaqueous solvent containing the electrolyte dissolved Examples of the metals in Group 1 of the periodic table therein . include lithium , sodium , potassium , and cesium . Preferred < 1 - 1 . Electrolyte > of these are lithium and sodium . Especially preferred is The electrolyte to be used in nonaqueous electrolyte 6 of lithium . the invention is not limited , and known ones for use as 60 Examples of the metals in Group 2 of the periodic table electrolytes in a target nonaqueous- electrolyte secondary include magnesium , calcium , strontium , and barium . Pre battery can be employed and mixed at will. In the case where ferred of these are magnesium and calcium . Especially nonaqueous electrolyte 6 of the invention is to be used in a preferred is magnesium . nonaqueous -electrolyte secondary battery , the electrolyte Examples of the metals in Group 13 of the periodic table preferably is one or more lithium salts . The electrolyte in 65 include aluminum , gallium , indium , and thallium . Preferred nonaqueous electrolyte 6 may be the same as that described of these are aluminum and gallium . Especially preferred is above with regard to nonaqueous electrolyte 1 . aluminum . US 9 ,853 , 326 B2 137 138 Preferred of these specific metals is lithium , sodium , and a halogen atom (hereinafter sometimes referred to as magnesium , calcium , aluminum , or gallium . More preferred “ specific carbonate ” ) as an aid for improving capacity is lithium , magnesium , or aluminum . Lithium is especially retentivity after high -temperature storage and cycle charac preferred . teristics, among those additives. The specific carbonate and One or more of such cyclic disulfonylimide salts repre - 5 other additives are separately explained below . sented by general formula ( 1 ) may be used . It is also possible < 1 -5 - 1 . Specific Carbonate > for the salt to have two or more kinds of cyclic disulfo The specific carbonate is a carbonate having at least either nylimide anions together with the M ' common to these . of an unsaturated bond and a halogen atom . The specific Namely , it is possible for the salt to have two or more kinds carbonate may have an unsaturated bond only or have a of cyclic disulfonylimide anions in the molecule . 10 halogen atom only , or may have both an unsaturated bond Examples of the cyclic disulfonylimide salt represented and a halogen atom . by general formula ( 1 ) include the lithium salt of cyclic The molecular weight of the specific carbonate is not 1 ,2 -ethanedisulfonylimide , lithium salt of cyclic 1 ,3 -pro particularly limited , and may be any desired value unless panedisulfonylimide , lithium salt of cyclic 1 , 2 -perfluoroeth - this considerably lessens the effects of invention 6 . How anedisulfonylimide , lithium salt of cyclic 1 , 3 -perfluoropro - 15 ever, the molecular weight thereof is generally 50 or higher , panedisulfonylimide , and lithium salt of cyclic 1 , 4 preferably 80 or higher, and is generally 250 or lower, perfluorobutanedisulfonylimide , and the like . preferably 150 or lower. When the molecular weight thereof Preferred of these are the lithium salt of cyclic 1 , 2 is too high , this specific carbonate has reduced solubility in perfluoroethanedisulfonylimide and the lithium salt of cyclic the nonaqueous electrolyte and there are cases where the 1 ,3 -perfluoropropanedisulfonylimide . 20 effect of the carbonate is difficult to produce sufficiently . The concentration of the cyclic disulfonylimide salt rep - Processes for producing the specific carbonate also are not resented by general formula ( 1 ) in the nonaqueous electro particularly limited , and a known process selected at will can lyte is preferably 0 . 001- 1 mol/ L . When the concentration of be used to produce the carbonate . the cyclic disulfonylimide salt is too low , there are cases Any one specific carbonate may be incorporated alone where it is difficult to sufficiently inhibit gas evolution 25 into nonaqueous electrolyte 6 of the invention , or any during high - temperature storage or capacity deterioration desired combination of two or more specific carbonates in through high - temperature storage. Conversely , too high con - any desired proportion may be incorporated thereinto . centrations thereof may result in cases where battery char The amount of the specific carbonate to be incorporated acteristics decrease through high -temperature storage . The into nonaqueous electrolyte 6 of the invention is not limited , concentration of the cyclic disulfonylimide salt is more 30 and may be any desired value unless this considerably preferably 0 .01 mol/ L or higher, especially preferably 0 .02 lessens the effects of invention 6 . It is , however, desirable mol/ L or higher, more preferably 0 .03 mol/ L or higher . The that the specific carbonate should be incorporated in a upper limit thereof is preferably 0 . 5 mol/ L or lower , more concentration which is generally 0 .01 % by mass or higher, preferably 0 . 3 mol/ L or lower , especially preferably 0 . 2 preferably 0 . 1 % by mass or higher , more preferably 0 . 3 % by mol/ L or lower . 35 mass or higher, and is generally 70 % by mass or lower, < 1 - 3 . Nonaqueous Solvent> preferably 50 % by mass or lower, more preferably 40 % by The nonaqueous solvent contained in nonaqueous elec - mass or lower, based on nonaqueous electrolyte 6 of the trolyte 6 of the invention is not particularly limited so long invention . as it is a solvent which does not adversely influence battery When the amount of the specific carbonate is below the characteristics after battery fabrication . However, it is pre - 40 lower limit of that range , there are cases where use of this ferred to employ one or more of the following solvents for nonaqueous electrolyte 6 of the invention in a nonaqueous use in nonaqueous electrolytes . electrolyte secondary battery results in difficulties in pro Examples of nonaqueous solvents in ordinary use include ducing the effect of sufficiently improving the cycle char acyclic and cyclic carbonates , acyclic and cyclic carboxylic acteristics of the nonaqueous- electrolyte secondary battery . acid esters , acyclic and cyclic ethers , phosphorus - containing 45 On the other hand , when the proportion of the specific organic solvents , and sulfur- containing organic solvents. carbonate is too high , there is a tendency that use of this These solvents are the same as those described above with nonaqueous electrolyte 6 of the invention in a nonaqueous regard to nonaqueous electrolytes 1 to 5 . electrolyte secondary battery results in decreases in the < 1 - 4 . Monofluorophosphate and Difluorophosphate > high - temperature storability and continuous - charge charac With respect to the “ monofluorophosphate and difluoro - 50 teristics of the nonaqueous - electrolyte secondary battery . In phosphate ” to be used in invention 6 , the kinds and contents particular, there are cases where gas evolution is enhanced thereof, places where the salts exist, methods of analysis , and capacity retentivity decreases. production process, etc . are the same as those described ( 1 - 5 - 1 - 1 . Unsaturated Carbonate ) above with regard to nonaqueous electrolyte 1 . The carbonate having an unsaturated bond ( hereinafter < 1 - 5 . Additives > 55 often referred to as “ unsaturated carbonate ” ) as one form of Nonaqueous electrolyte 6 of the invention may contain the specific carbonate according to invention 6 is the same various additives so long as these additives do not consid - as that described above with regard to nonaqueous electro erably lessen the effects of invention 6 . In the case where lyte 1 . additives are additionally incorporated to prepare the non - ( 1 - 5 - 1 - 2 . Halogenated Carbonate ) aqueous electrolyte , conventionally known additives can be 60 On the other hand , the carbonate having a halogen atom used at will. One additive may be used alone, or any desired (hereinafter often referred to as “ halogenated carbonate ” ) as combination of two or more additives in any desired pro - another form of the specific carbonate according to inven portion may be used . tion 6 is not particularly limited so long as it is a carbonate Examples of the additives include overcharge inhibitors having a halogen atom , and any desired halogenated car and aids for improving capacity retentivity after high - tem - 65 bonate can be used . This “ halogenated carbonate ” is the perature storage and cycle characteristics . It is preferred to same as that described above with regard to nonaqueous add a carbonate having at least either of an unsaturated bond electrolyte 2 . US 9 ,853 , 326 B2 139 140 ( 1 -5 - 1 -3 . Halogenated Unsaturated Carbonate ) ever , the invention should not be construed as being limited Furthermore usable as the specific carbonate is a carbon - to the following Examples unless the invention departs from ate having both an unsaturated bond and a halogen atom the spirit thereof. ( this carbonate is suitably referred to as “ halogenated unsaturated carbonate ” ) . This halogenated unsaturated car - 5 Example 1 of Nonaqueous Electrolyte 1 bonate is not particularly limited , and any desired haloge nated unsaturated carbonate can be used unless the effects of < Production of Nonaqueous- Electrolyte Secondary Battery, 1 > invention 6 are considerably lessened thereby . This " halo [ Production of Positive Electrode] genated unsaturated carbonate ” is the same as that described 10 Eighty - five parts by weight of LiCo02 ( “ C5 ” , manufac above with regard to nonaqueous electrolyte 2 . tured by Nippon Chemical Industrial Co . , Ltd . ) was used as < 1 - 5 - 2 . Other Additives > a positive - electrode active material and mixed with 6 parts Additives other than the specific carbonate are explained by weight of a carbon black and 9 parts by weight of below . Examples of additives other than the specific car poly ( vinylidene fluoride ) ( trade name “ KF - 1000 ” , manufac bonate include overcharge inhibitors and aids for improving 15 tured by Kureha Chemical Industry Co . Ltd .) . N -Methyl capacity retentivity after high - temperature storage and cycle 2 -pyrrolidone was added to the mixture to slurry it . This characteristics. slurry was evenly applied to each side of an aluminum foil < 1 - 5 - 2 - 1 . Overcharge Inhibitor > having a thickness of 15 um and dried . Thereafter , the coated The " overcharge inhibitor ” is the same as that described foil was pressed so as to result in positive - electrode active above with regard to nonaqueous electrolyte 1 . 20 material layers having a density of 3 .0 g/ cm ". Thus , a < 1 - 5 - 2 -2 . Aids > positive electrode was obtained . On the other hand , examples of the aids for improving [Production of Negative Electrode ] capacity retentivity after high -temperature storage and cycle To 98 parts by weight of artificial- graphite powder KS -44 characteristics include the same compounds as those enu - ( trade name; manufactured by Timcal) were added 100 parts merated above with regard to nonaqueous electrolyte 1 . 25 by weight of an aqueous dispersion of sodium carboxym [ 2 . Nonaqueous- Electrolyte Secondary Battery ] ethyl cellulose ( concentration of sodium carboxymethyl Nonaqueous- electrolyte secondary battery 6 of the inven - cellulose , 1 % by mass ) as a thickener and 2 parts by weight tion includes: a negative electrode and a positive electrode of an aqueous dispersion of a styrene /butadiene rubber (concentration of styrene /butadiene rubber, 50 % by mass ) as which are capable of occluding and releasing ions; and the 30 a binder. The ingredients were mixed together by means of nonaqueous electrolyte 6 of the invention . a disperser to obtain a slurry . The slurry obtained was < 2 - 1 . Battery Constitution > applied to one side of a copper foil having a thickness of 12 Nonaqueous - electrolyte secondary battery 6 of the inven um and dried . Thereafter, the coated foil was pressed so as tion may have the same battery constitution as that described to result in a negative - electrode active -material layer having above with regard to nonaqueous -electrolyte e secondary balbat -. 35z a density of 1 . 5 g / cmº. Thus, a negative electrode was tery 1 . obtained . < 2 - 2 . Nonaqueous Electrolyte > [Nonaqueous Electrolyte ] As the nonaqueous electrolyte , the nonaqueous electrolyte In a dry argon atmosphere , LiPF , which each had been 6 of the invention described above is used . Incidentally , a sufficiently dried was dissolved , in an amount of 1 mol/ L , in mixture of nonaqueous electrolyte 6 of the invention and 40 a nonaqueous solvent prepared by mixing in the proportion another nonaqueous electrolyte may be used so long as this shown in Table 1 . Thus , a nonaqueous electrolyte was is not counter to the spirit of invention 6 . prepared . Furthermore , a monofluorophosphate and /or a < 2 - 3 . Negative Electrode > difluorophosphate was dissolved in the solution so as to The negative electrode of nonaqueous- electrolyte second result in the respective concentrations shown in Table 1 . ary battery 6 may be the same as the negative electrode 45 Thus, a desired nonaqueous electrolyte was obtained . described above with regard to nonaqueous - electrolyte sec - [Fabrication of Nonaqueous - Electrolyte Secondary Batteryl ondary battery 1 . The positive electrode and negative electrode described < 2 - 4 . Positive Electrode > above and a separator made of polyethylene were super The positive electrode of nonaqueous- electrolyte second posed in the order of negative electrode /separator / positive electrode 50 electrode/ separator / negative electrode to produce a battery ary battery 6 may be the same as the positive electrode 5o elecelement . This battery element was inserted into a bag described above with regard to nonaqueous - electrolyte sec constituted of a laminated film obtained by coating both ondary battery 1 . sides of aluminum ( thickness, 40 um ) with a resin layer , with < 2 - 5 . Separator > terminals of the positive and negative electrodes projecting The separator of nonaqueous- electrolyte secondary bat 55 outward . Thereafter , 0 . 5 mL of the nonaqueous electrolyte tery 6 may be the same as the separator described above with was introduced into the bag, and this bag was vacuum - sealed regard to nonaqueous- electrolyte secondary battery 1 . to produce a sheet battery . < 2 -6 . Battery Design > < Evaluation of Nonaqueous - Electrolyte Secondary Battery The battery design of nonaqueous - electrolyte secondary for High - Temperature Storability > battery 6 may be the same as the battery design described 60 The battery in a sheet form was evaluated in the state of above with regard to nonaqueous - electrolyte secondary bat - being sandwiched between glass plates in order to enhance tery 1 . contact between the electrodes . At 25° C . , this battery was subjected to 3 cycles of charge/ discharge at a constant EXAMPLES current corresponding to 0 . 2 C and at a final charge voltage 65 of 4 . 2V and a final discharge voltage of 3V to stabilize the The invention will be explained below in more detail by battery. In the fourth cycle , the battery was subjected to 4 .4V reference to Examples and Comparative Examples. How constant- current constant- voltage charge (CCCV charge ) US 9 ,853 , 326 B2 141 142 ( 0 . 05 C cutting ) in which the battery was charged to a final The residual capacity and recovery capacity ( % ) in the charge voltage of 4 . 4V at a current corresponding to 0 . 5 C case where the discharge capacity as measured before the and further charged until the charge current value reached a high - temperature storage is taken as 100 are shown in Table current value corresponding to 0 .05 C . Thereafter, this battery was subjected to 3V discharge at a constant current 5 corresponding to 0 . 2 C to determine the discharge capacity of the battery before high -temperature storage . This battery Example 2 of Nonaqueous Electrolyte 1 to was subjected again to 4 . 4V CCCV ( 0 .05 C cutting) charge Example 55 of Nonaqueous Electrolyte 1 and and then stored at a high temperature under the conditions of Comparative Example 1 for Nonaqueous 85° C . and 24 hours . Electrolyte 1 to Comparative Example 12 for Before and after the high -temperature storage , the sheet 10 Nonaqueous Electrolyte 1 battery was immersed in an ethanol bath . The amount of the gas evolved was determined from the resultant volume change . The battery which had undergone the storage was Desired aqueous electrolytes were prepared in the same discharged at 25° C . and a constant current of 0 . 2 C to a final manner as in Example 1 of Nonaqueous Electrolyte 1 , discharge voltage of 3V to obtain the residual capacity after 15 except that the nonaqueous solvent and the monofluoro the storage test. This battery was subjected again to 4 . 4V phosphate and / or difluorophosphate which are shown in CCCV ( 0 . 05 C cutting ) charge and then discharged to 3V at Tables 1 to 5 were used so as to result in the contents shown a current value corresponding to 0 . 2 C to determine the 0 . 2 in Tables 1 to 5 . Nonaqueous - electrolyte secondary batteries C capacity and thereby obtain the 0 . 2 C capacity of the were produced and then evaluated for high - temperature battery which had undergone the storage test . This capacity 20 storability in the same manner as in Example 1 ofNonaque was taken as recovery capacity . “ 1 C ” means a current value ous Electrolyte 1 . The results thereof are shown in Table 1 at which the battery can be fully charged by 1 -hour charge . to Table 5 . TABLE 1 Results of evaluation of high temperature storability Storage Residual Recovery Monofluorophosphate and /or swell capacity capacity Nonaqueous solvent (mass % ) difluorophosphate (mass % ) (mL ) ( % ) ( % ) Example 1 ethylene carbonate + lithium difluorophosphate 0 .18 82 8 9 ethyl methyl carbonate + (0 . 5 ) fluoroethylene carbonate ( 35 . 4 :63 . 6 : 1 . 0 ) Example 2 ethylene carbonate + lithium difluorophosphate 0 . 14 80 ethyl methyl carbonate + (0 . 5 ) fluoroethylene carbonate ( 35 . 7 :64 . 1 : 0 . 2 ) Example 3 ethylene carbonate + lithium difluorophosphate 0 . 22 83 88 ethyl methyl carbonate + ( 0 . 5 ) fluoroethylene carbonate ( 34 . 0 :61 . 0 : 5 . 0 ) Example 4 ethylene carbonate + lithium difluorophosphate 0 .1983 19 ethylmethyl carbonate + la( 0 . 5 ) 4 ,5 - difluoroethylene carbonate ( 35 . 4 :63 . 6 : 1 . 0 ) Example 5 ethylene carbonate + lithium difluorophosphate 0 . 20 ethylmethyl carbonate + ( 0 . 5 ) 4 - fluoro - 5 -methylethylene carbonate la ( 35 . 4 :63 . 6 : 1 . 0 ) Example 6 ethylene carbonate + lithium difluorophosphate 0 . 21 81 ethyl methyl carbonate + la( 0 . 5 ) 4 - ( fluoromethyl) ethylene carbonate (35 . 4 :63 . 6 : 1 . 0 ) Example 7 ethylene carbonate + lithium difluorophosphatedifluor osphate 0 . 22 83 ethyl methyl carbonate + la( 0 . 5 ) 4 - (trifluoromethyl ) ethylene carbonate ( 35 . 4 :63 . 6 : 1 . 0 ) Example 8 ethylene carbonate + lithium difluorophosphate 0 . 20 ethyl methyl carbonate + ( 0 . 5 ) fluoroethylene carbonate + 2 , 2 - difluoroethyl methyl carbonate (35 . 4 :63 . 6 : 0 . 5 : 0 . 5 ) Example 9 ethylene carbonate + lithium difluorophosphate 0 .22 81 ethyl methyl carbonate + ( 0 . 1 ) fluoroethylene carbonate ( 35 . 4 :63 . 6 : 1 . 0 ) Example 10 ethylene carbonate + lithium difluorophosphate 0 . 13 ethylmethyl carbonate + ( 1 . 0 ) fluoroethylene carbonate liiiiiiiiii (35 . 4 :63 . 6 : 1 . 0 ) US 9 ,853 , 326 B2 143 144 TABLE 1 -continued Results of evaluation of high temperature storab Storage Residual Recovery Monofluorophosphate and/ or swell capacity capacity Nonaqueous solvent (mass % ) difluorophosphate (mass % ) (mL ) ( % ) ( % ) Example 11 ethylene carbonate + sodium difluorophosphate 0 .20 8 3 87 ethyl methyl carbonate + ( 0 . 5 ) fluoroethylene carbonate ( 35 . 4 :63 . 6 : 1 . 0 ) Example 12 ethylene carbonate + dilithium monofluoro 0 .21 ethyl methyl carbonate + phosphate 0. 21 82 85 fluoroethylene carbonate (0 . 5 ) ( 35 . 4 :63 . 6 : 1 . 0 ) Example 13 ethylene carbonate + lithium difluorophosphate 0. 23 82 86 ethyl methyl carbonate + ( 0 . 5 ) fluoroethylene carbonate + vinylene carbonate ( 35. 0 :63 . 0 : 1 .0 : 1 . 0 )

TABLE 2 Results of evaluation of high temperature storability Storage Residual Recovery Monofluorophosphate and / or swell capacity capacity Nonaqueous solvent (wt % ) difluorophosphate ( wt % ) (mL ) ( % ) ( % ) Example 14 fluoroethylene carbonate + Lithium difluorophosphate 0. 22 81 88 ethyl methyl carbonate ( 0 . 5 ) s (38 . 8 :61 . 2 ) Example 15 fluoroethylene carbonate + Lithium difluorophosphate 0 . 15 82 ethyl methyl carbonate ( 0 . 5 ) o ( 20 . 7 :79 . 3 ) Example 16 fluoroethylene carbonate + Lithium difluorophosphate 0 . 24 80 son ethyl methyl carbonate ( 0 . 5 ) (59 . 6 :40 . 4 ) Example 17 fluoroethylene carbonate + Lithium difluorophosphate 0 . 16 81 asa ethylene carbonate + (0 .5 ) ethyl methyl carbonate ( 17 . 5 : 19 . 9 :62 . 6 ) Example 18 4 , 5 - difluoraethylene carbonate + Lithium difluorophosphate 0 . 22 80 opne ethyl methyl carbonate ( 0 . 5 ) (38 . 9 :61 . 1 . 0 ) Example 19 4 - fluoro - 5 -methylethylene carbonate + Lithium difluorophosphate 0 . 20 82 act ethyl methyl carbonate ( 0 . 5 ) (36 . 5 :63 . 5 . 0 ) Example 20 4 - ( fluoromethyl) ethylene carbonate + Lithium difluorophosphate 0 . 18 cont ethyl methyl carbonate ( 0 . 5 ) associadosalos ( 36 . 2 :63 . 8 ) Example 21 4 - ( trifluoromethyl ) ethylene carbonate + Lithium difluorophosphate 0 . 17 81 con ethyl methyl carbonate ( 0 . 5 ) ( 39 . 8 :60 . 2 ) Example 22 fluoroethylene carbonate + Lithium difluorophosphate 0 . 24 80 e ethyl methyl carbonate ( 0 . 1 ) (38 . 8 :61 . 2 ) Example 23 fluoroethylene carbonate + Lithium difluorophosphate 0 . 16 81 sona ethyl methyl carbonate ( 1 . 0 ) ( 38 . 8 :61 . 2 ) Example 24 fluoroethylene carbonate + Sodium difluorophosphate 0 .20 80 ethyl methyl carbonate ( 0 . 5 ) (38 . 8 :61 . 2 ) s Example 25 fluoroethylene carbonate + Dilithium monofluoro 0 .22 81 con ethyl methyl carbonate phosphate (38 . 8 :61 . 2 ) ( 0 . 5 ) Example 26 fluoroethylene carbonate + Lithium difluorophosphate 0 . 21 82 D ethyl methyl carbonate + (0 . 5 ) ethyl 2 , 2 - difloroethyl carbonate (38 . 4 :60 . 6 : 1 . 0 ) Example 27 fluoroethylene carbonate + Lithium difluorophosphate 0 . 19 8080 84 ethyl methyl carbonate + ( 0 . 5 ) ethyl ( 2 , 2 - difloroethyl ) carbonate iiiiiiiiiii (38 . 1 :51 . 6 : 10 . 3 ) US 9 ,853 , 326 B2 145 146 TABLE 2 -continued Results of evaluation of high temperature storability Storage Residual Recovery Monofluorophosphate and/ or swell capacity capacity Nonaqueous solvent (wt % ) difluorophosphate (wt % ) (mL ) ( % ) ( % ) Example 28 fluoroethylene carbonate + Lithium difluorophosphate 0. 18 83 86 ethyl methyl carbonate + (0 .5 ) bis (2 , 2 , 2 -trifloroethyl ) carbonate (37 . 2 :50 . 3 : 12. 5 ) Example 29 fluoroethylene carbonate + Lithium difluorophosphate 0 .24 24 8282 88 ethyl methyl carbonate + ( 0 .5 ) vinylene carbonate (38 . 4 :60 . 6 : 1 . 0 )

TABLE 3 Results of evaluation of high temperature storability Storage Residual Recovery Monofluorophosphate and /or swell capacity capacity Nonaqueous solvent (mass % ) difdifluorophosphate (mass % ) (mL ) ( % ) ( % ) Example 30 ethylene carbonate + Lithium difluorophosphate 0 . 23 82 89 ethyl methyl carbonate + ( 0 . 5 ) ethyl- ( 2 , 2 - difluoroethyl ) carbonate ( 35 . 4 :63 . 6 : 1 . 0 ) Example 31 ethylene carbonate + Lithium difluorophosphate 0 .20 83 ethyl methyl carbonate + (0 . 5 ) ethyl- ( 2 ,2 - difluoroethyl ) carbonate (35 . 7 :64 . 1 : 0 . 2 ) Example 32 ethylene carbonate + Lithium difluorophosphate 0 .. 24 81 a ethyl methyl carbonate + ( 0 . 5 ) ethyl- ( 2 , 2 -difluoroethyl ) carbonate (34 . 0 :61 . 0 : 5 . 0 ) Example 33 ethylene carbonate + Lithium difluorophosphate 0 . 23 83 88 ethyl methyl carbonate + (0 . 5 ) de ethyl- ( 2 , 2 , 2 - trifluoroethyl) carbonate ( 35 . 4 :63 . 6 : 1 . 0 ) Example 34 ethylene carbonate + Lithium difluorophosphate 0 . 21 ethyl methyl carbonate + ( 0 . 5 ) bis ( 2 , 2 , 2 - trifluoroethyl) carbonate ( 35 . 4 :63 . 6 : 1 . 0 ) Example 35 ethylene carbonate + Lithium difluorophosphate 0 . 22 22 81 88 ethyl methyl carbonate + ( 0 . 5 ) fluoromethyl methyl carbonate ( 35 . 4 :63 . 6 : 1 . 0 ) Example 36 ethylene carbonate + Lithium difluorophosphate 0 . 22 22 82 ethyl methyl carbonate + ( 0 . 5 ) bis (monofluoromethyl ) carbonate ( 35 . 4 :63 . 6 : 1 . 0 ) Example 37 ethylene carbonate + Lithium difluorophosphate 0 . 25 81 ethyl methyl carbonate + ( 0 . 1 ) ethyl- (2 , 2 -difluoroethyl ) carbonate (35 , 4 :63 . 6 : 1 . 0 ) Example 38 ethylene carbonate + Lithium difluorophosphate 0 . 16 81 ethyl methyl carbonate + ( 1 . 0 ) ethyl- ( 2 , 2 - difluoroethyl ) carbonate (35 . 4 :63 . 6 : 1 . 0 ) Example 39 ethylene carbonate + Sodium difluorophosphate 0 . 24 83 ethyl methyl carbonate + ( 0 . 5 ) ethyl- ( 2 , 2 - difluoroethyl) carbonate (35 . 4 :63 . 6 : 1 . 0 ) Example 40 ethylene carbonate + Dilithium monofluoro 0 . 23 82 ethyl methyl carbonate + phosphate ethyl- ( 2 , 2 -difluoroethyl ) carbonate ( 0 . 5 ) (35 . 4 :63 . 6 : 1 . 0 ) Example 41 ethylene carbonate + Lithium difluorophosphate 0 . 25 83 89 ethyl methyl carbonate + ( 0 . 5 ) ethyl- ( 2 , 2 - difluoroethyl) carbonate + vinylene carbonate iiliiiiiiiii ( 35 . 0 :63 . 0 : 1 . 0 : 1 . 0 ) US 9 ,853 , 326 B2 147 148 TABLE 4 . Results of evaluation of high temperature storability Storage Residual Recovery Monofluorophosphate and / or swell capacity capacity Nonaqueous solvent (mass % ) difluorophosphate (mass % ) (mL ) ( % ) (% ) Example 42 ethylene carbonate + Lithium difluorophosphate 0 .21 21 8080 8 866 ethyl- ( 2 , 2 - difluoroethyl) carbonate ( 0 . 5 ) (31 . 8 :68 . 2 ) Example 43 ethylene carbonate + Lithium difluorophosphate 0 . 22 ethyl - ( 2 , 2 - difluoroethyl) carbonate ( 0 . 5 ) 0 .22 81 ( 16 . 1 :83 . 9 ) Example 44 ethylene carbonate + Lithium difluorophosphate 0 . 20 8 ethyl- ( 2, 2 -difluoroethyl ) carbonate (0 . 5 ) (52 . 1 :47 . 9 ) Example 45 ethylene carbonate + Lithium difluorophosphate 0 . 20 880 ethyl methyl carbonate + ( 0 . 5 ) ethyl- ( 2 , 2 -difluoroethyl ) carbonate (35 . 1 :54 . 1 : 10 . 8 ) Example 46 ethylene carbonate + Lithium difluorophosphateate 0 . 22 8 ethyl methyl carbonate + (0 .5 ) ethyl- ( 2 ,2 ,2 - trifluoroethyl) carbonate (35 . 0 :54 . 0 : 11. 0 ) Example 47 ethylene carbonate + Lithium difluorophosphate 0 . 22 8 ethyl methyl carbonate + ( 0 . 5 ) bis ( 2 , 2 , 2 -trifluoroethyl ) carbonate (34 . 2 :52 . 7 : 13 . 1 ) Example 48 ethylene carbonate + Lithium difluorophosphate 0 .1979 19 8 ethyl methyl carbonate + (0 . 5) fluoromethyl methyl carbonate (35 .0 :54 . 0 :11 . 0 ) Example 49 ethylene carbonate + Lithium difluorophosphate 00 .1978 19 8 ethyl methyl carbonate + ( 0 . 5 ) bis (monofluoromethyl ) carbonate ( 34 . 5 :53 . 2 :12 . 3 ) Example 50 ethylene carbonate + Lithium difluorophosphate 00 . 24 880 ethyl 2 , 2 - difluoroethyl carbonate ( 0 . 1 ) (31 . 8 :68 . 2 ) Example 51 ethylene carbonate + Lithium difluorophosphate 0 . 15 8 ethyl- ( 2 ,2 -difluoroethyl ) carbonate ( 1 . 0 ) (31 . 8 : 68 . 2 ) Example 52 ethylene carbonate + Sodium difluorophosphate 0 . 22 8 ethyl- ( 2 , 2 -difluoroethyl )carbonate (0 .5 ) ( 31 . 8 :68 . 2 ) Example 53 ethylene carbonate + Dilithium monofluoro 0 . 21 8 ethyl- ( 2 , 2 -difluoroethyl ) carbonate phosphate ( 31. 8 :68 . 2 ) ( 0 . 5 ) Example 54 ethylene carbonate + Lithium difluorophosphate 00 . 22 81 ethyl- ( 2 , 2 - difluoroethyl) carbonate + (0 . 5 ) ??? fluoroethylene carbonate (31 . 5 :67 . 5 : 1 . 0 ) Example 55 ethylene carbonate + Lithium difluorophosphate 0 ..24 8282 8 7 ethyl- ( 2 , 2 -difluoroethyl ) carbonate + ( 0 . 5 ) vinylene carbonate (31 . 5 :67 . 5 : 1 . 0 )

TABLE 5 Results of evaluation of high temperature storability Storage Residual Recovery Monofluorophosphate and / or swell capacity capacity Nonaqueous solvent (mass % ) difluorophosphate (mass % ) (mL ) (% ) Comparative ethylene carbonate + 0 . 27 67 Example 1 ethyl methyl carbonate 0 . 27 62 ( 35 . 8 :64 . 2 ) Comparative ethylene carbonate + 0 . 35 Example 2 ethyl methyl carbonate + 0. 35 66 76 fluoroethylene carbonate ( 35 . 4 :63 . 6 : 1 . 0 ) Comparative ethylene carbonate + lithium difluorophosphate 0 . 20 67 78 Example 3 ethyl methyl carbonate ( 0 . 5 ) ( 35 . 8 :64 . 2 ) US 9 ,853 , 326 B2 149 150 TABLE 5 - continued Results of evaluation of high temperature storability Storage Residual Recovery Monofluorophosphate and / or swell capacity capacity Nonaqueous solvent (mass % ) difluorophosphate (mass % ) (mL ) ( % ) (% ) Comparative ethylene carbonate + 0 . 42 67 8383 Example 4 ethyl methyl carbonate + vinylene carbonate ( 35 . 4 :63 . 6 : 1 . 0 ) Comparative ethylene carbonate + 0 . 45 Example 5 ethyl methyl carbonate + on fluoroethylene carbonate + vinylene carbonate ( 35 . 0 :63 . 0 : 1 . 0 : 1 . 0 ) Comparative ethylene carbonate + lithium difluorophosphate 0 . 39 67 as Example 6 ethyl methyl carbonate + ( 0 . 5 ) vinylene carbonate (35 . 4 :63 . 6 : 1 . 0 ) Comparative fluoroethylene carbonate + 0 . 37 & Example 7 ethyl methyl carbonate e ( 38 . 8 :61 . 2 ) Comparative fluoroethylene carbonate + 0 . 47 § Example 8 ethyl methyl carbonate + f vinylene carbonate (38 . 4 :60 . 6 : 1 . 0 ) Comparative ethylene carbonate + 0 . 33 6 $ Example 9 ethyl methyl carbonate + ethyl difluoroethyl carbonate ( 35 . 4 :63 . 6 : 1 . 0 ) Comparative ethylene carbonate + 00 .44 68 about Example 10 ethyl methyl carbonate + ethyl difluoroethyl carbonate + vinylene carbonate (35 . 0 :63 . 0 : 1 . 0 : 1 . 0 ) Comparative ethylene carbonate + 0 . 30 s Example 11 ethyl- ( 2 ,2 - difluoroethyl ) carbonate s ( 31 . 8 :68 . 2 ) Comparative ethylene carbonate + 0 . 45 Example 12 ethyl- ( 2 , 2 -difluoroethyl ) carbonate + e vinylene carbonate (31 . 5 :67 . 5 : 1 . 0 )

The following is apparent from Table 1 to Table 5 . The an aqueous Electrolyte 1 , in which the electrolytes contained nonaqueous -electrolyte secondary batteries 1 produced both of these compounds, were ascertained to have been using the nonaqueous electrolytes 1 of the invention , which improved in both inhibition of swelling during high - tem contained at least one carbonate having a halogen atom and perature storage and inhibition of deterioration in battery further contained a monofluorophosphate and / or a difluoro - characteristics ( for example , comparison between Example phosphate , were inhibited from swelling during high -tem - 45 1 of Nonaqueous Electrolyte 1 and Comparative Example 2 perature storage and from deteriorating in battery charac - for Nonaqueous Electrolyte 1 ; comparison between teristics represented by residual capacity and recovery Example 1 of Nonaqueous Electrolyte 1 to Example 8 of capacity , as compared with the nonaqueous - electrolyte sec - Nonaqueous Electrolyte 1 and Comparative Example 3 for ondary batteries produced using the nonaqueous electrolytes Nonaqueous Electrolyte 1 ; and comparison between containing one of these compounds (Comparative Example 50 Example 13 of Nonaqueous Electrolyte 1 and Comparative 2 for Nonaqueous Electrolyte 1 , Comparative Example 3 for Example 5 for Nonaqueous Electrolyte 1 ) . The same effect Nonaqueous Electrolyte 1 , and Comparative Examples 5 to was observed also in the case where nonaqueous electrolytes 12 for Nonaqueous Electrolyte 1 ) or using the nonaqueous contained vinylene carbonate, which is an example of the electrolytes containing neither of those compounds ( Com specific carbonate . parative Example 1 for Nonaqueous Electrolyte 1 and Com - 55 parative Example 4 for Nonaqueous Electrolyte 1 ) . Example 56 of Nonaqueous Electrolyte 1 to Specifically , the electrolytes produced in Example 1 of Example 74 of Nonaqueous Electrolyte 1 and Nonaqueous Electrolyte 1 to Example 55 of Nonaqueous Comparative Example 13 for Nonaqueous Electrolyte 1 were effective in inhibiting swelling during Electrolyte 1 to Comparative Example 24 for high -temperature storage and in inhibiting deterioration in 60 Nonaqueous Electrolyte 1 battery characteristics , as compared with Comparative Example 1 for Nonaqueous Electrolyte 1 and Comparative pared with the Comparative Examples for Nonaqueous Subsequently , nonaqueous - electrolyte secondary batteries Electrolyte 1 in which the electrolytes contained only either 65 were produced in the same manner as in Example 1 of of a carbonate having a halogen atom and a monofluoro - Nonaqueous Electrolyte 1 , except that the negative electrode phosphate and/ or difluorophosphate , the Examples of Non used in Example 1 of Nonaqueous Electrolyte 1 was US 9 ,853 , 326 B2 151 152 replaced with the silicon - alloy negative electrode described < Evaluation of Nonaqueous- Electrolyte Secondary Battery below , and that the nonaqueous electrolytes to be used were for High - Temperature Storability > prepared in the following manner. The compounds shown in Each of the batteries in a sheet form was evaluated in the each of the rows of the Examples of Nonaqueous Electrolyte state of being sandwiched between glass plates in order to 5 enhance contact between the electrodes . At 25° C ., this 1 and the Comparative Examples for Nonaqueous Electro - 5 battery was subjected to 3 cycles of charge / discharge at a lyte 1 in the column “ Nonaqueous solvent" and the column constant current corresponding to 0 . 2 C and at a final charge “ Monofluorophosphate and / or difluorophosphate ” in Table 6 voltage of 4 .2V and a final discharge voltage of 3V to to Table 8 were mixed together in the proportion shown stabilize the battery . In the fourth cycle , the battery was therein . Furthermore , LiPF6 was dissolved as an electrolyte subjected to 4 .2V constant -current constant - voltage charge salt as to result in a concentration of 1 mol/ L . Thus, desired " (CCCV charge) ( 0 . 05 C cutting ) in which the battery was nonaqueous electrolytes (nonaqueous electrolytes of charged to a final charge voltage of 4 .2V at a current Example 56 of Nonaqueous Electrolyte 1 to Example 74 of corresponding to 0 . 5 C and further charged until the charge Nonaqueous Electrolyte 1 and Comparative Example 13 for current value reached a current value corresponding to 0 .05 Nonaqueous Electrolyte 1 to Comparative Example 24 for C . Thereafter, this battery was subjected to 3V discharge at 15 a constant current corresponding to 0 . 2 C to determine the Nonaqueous Electrolyte 1 ) were prepared and used . discharge capacity of the battery before high -temperature [Production of Silicon - Alloy Negative Electrode ] storage . This battery was subjected again to 4 . 2V -CCCV As negative - electrode active materials , use was made of ( 0 . 05 C cutting ) charge and then stored at a high temperature 73. 2 parts by weight of silicon and 8 . 1 part by weight of under the conditions of 85° C . and 3 days . copper as non - carbon materials and 12 .2 parts by weight of 20 Before and after the high - temperature storage , the sheet battery was immersed in an ethanol bath . The amount of the an artificial - graphite powder (“ KS -6 ” , manufactured by gas evolved was determined from the resultant volume Timcal ) . Thereto were added 54 . 2 parts by weight of an change . The battery which had undergone the storage was N -methylpyrrolidone solution containing 12 parts by weight discharged at 25° C . and a constant current of 0 . 2 C to a final of poly ( vinylidene fluoride ) (hereinafter abbreviated to 25 discharge voltage of 3V to obtain the residual capacity after the storage test. This battery was subjected again to 4 . 2V " PVDF” ) and 50 parts by weight of N -methylpyrrolidine . CCCV ( 0 .05 C cutting ) charge and then discharged to 3V at The ingredients were mixed together by means of a disperser a current value corresponding to 0 . 2 C to determine the 0 . 2 to slurry the mixture . The slurry obtained was evenly applied C capacity and thereby obtain the 0 .2 C capacity of the to a copper foil having a thickness of 18 um as a negative - battery which had undergone the storage test . This capacity electrode current collector. This coating was first allowed to 30 was taken as recovery capacity . “ 1 ” means a current value at which the battery can be fully charged by 1 - hour charge . dry naturally and thereafter finally dried at 85° C . for a The residual capacity and recovery capacity ( % ) in the whole day and night under reduced pressure. The resultant case where the discharge capacity as measured before the coated foil was pressed so as to result in an electrode density high -temperature storage is taken as 100 are shown in Table of about 1 . 5 g / cm3. Thus , a negative electrode was obtained . 6 to Table 8 . TABLE 6 Results of evaluation of high temperature storability Storage Residual Recovery Monofluorophosphate and /or swell capacity capacity Nonaqueous solvent (mass % ) difluorophosphate (mass % ) 11.(mL ) ( % ) ( % ) Example 56 ethylene carbonate + lithium difluorophosphate 0 .25 82 89 diethyl carbonate + ( 0 . 5 ) fluoroethylene carbonate (36 . 3 :62 . 7 : 1 . 0 ) Example 57 ethylene carbonate + lithium difluorophosphate 00 . 26 84 diethyl carbonate + (0 .5 ) 4 , 5 - difluoroethylene carbonate ( 36 . 3 :62 . 7 : 1 . 0 ) Example 58 ethylene carbonate + lithium difluorophosphate 0 . 28 83 diethyl carbonate + (0 . 5 ) 4 - (trifluoromethyl ) ethylene carbonate ( 36 . 3 :62 . 7 : 1 . 0 ) Example 59 ethylene carbonate + lithium difluorophosphate 0 .28 28 82 87 diethyl carbonate + ( 0 . 5 ) fluoroethylene carbonate + vinylene carbonate ( 35 . 9 :62 . 1 : 1 . 0 : 1 . 0 ) Example 60 fluoroethylene carbonate + lithium difluorophosphate 0 .25 diethyl carbonate ( 0 . 5 ) (39 . 7 :60 . 3 ) Example 61 fluoroethylene carbonate + lithium difluorophosphate 0 . 22 so ethylene carbonate + ( 0 . 5 ) diethyl carbonate (17 . 920 . 3 :61 . 8 ) Example 62 4 ,5 -difluoroethylene carbonate + lithium difluorophosphate 0 .25 82 90 diethyl carbonate (0 . 5 ) ( 39 . 9 :60 . 1 ) US 9 ,853 , 326 B2 153 154 TABLE 6 -continued Results of evaluation of high temperature storability

Storage Residual Recovery Monofluorophosphate and/ or swell capacity capacity Nonaqueous solvent (mass % ) difluorophosphate (mass % ) (mL ) ( % ) ( % )

Example 63 4 -( trifluoromethyl )ethylene carbonate + lithium difluorophosphatehale 0 . 20 83 89 diethyl carbonate ( 0 . 5 ) ( 40 . 7 :59 . 3 ) Example 64 fluoroethylene carbonate + lithium difluorophosphate 0. 27 84 91 diethyl carbonate + (0 .5 ) vinylene carbonate ( 39 . 7 : 59 . 3 :1 )

TABLE 7 Results of evaluation of high temperature storability Storage Residual Recovery Monofluorophosphate and /or swell capacity capacity Nonaqueous solvent (mass % ) difluorophosphate (mass % ) (mL ) ( % ) ( % ) Example 65 ethylene carbonate + lithium difluorophosphate 0. 27 81 89 diethyl carbonate + ( 0 . 5 ) ethyl- (2 , 2 -difluoroethyl ) carbonate ( 36 . 3 :62 . 7 : 1 . 0 ) Example 66 ethylene carbonate + lithium difluorophosphate 00 . 27 82 diethyl carbonate + ( 0 . 5 ) ethyl- ( 2 , 2 , 2 -trifluoroethyl ) carbonate reat (36 . 3 :62 . 7 : 1 . 0 ) Example 67 ethylene carbonate + lithium difluorophosphate 0 .. 25 83 88 diethyl carbonate + ( 0 . 5 ) bis( 2 ,2 ,2 - trifluoroethyl) carbonate (36 . 3 :62 . 7 : 1 . 0 ) Example 68 ethylene carbonate + lithium difluorophosphate 0 . 28 diethyl carbonate + ( 0 . 5 ) ethyl- ( 2 , 2 - difluoroethyl ) carbonate + vinylene carbonate g (35 . 9 :62 . 1 : 1 . 0 : 1 . 0 ) Example 69 ethylene carbonate + lithium difluorophosphate 0 .25 ethyl- ( 2 , 2 - difluoroethyl ) carbonate (0 . 5 ) (31 . 8 :68 . 2 ) Example 70 ethylene carbonate + lithium difluorophosphate 0 .. 24 81 diethyl carbonate + ( 0 . 5 ) ethyl - ( 2 , 2 - difluoroethyl) carbonate (35 .953 . 1: 11 . 0 ) Example 71 ethylene carbonate + lithium difluorophosphate 0 . 26 83 diethyl carbonate + (0 . 5 ) as ethyl- ( 2 , 2 , 2 - trifluoroethyl ) carbonate (35 . 8 :53 . 0 : 11. 3 ) Example 72 ethylene carbonate + lithium difluorophosphate 0 . 26 83 diethyl carbonate + (0 . 5 ) bis (2 , 2, 2 - trifluoroethyl) carbonate ( 34 . 9 :51 . 7 :13 . 4 ) you Example 73 ethylene carbonate + lithium difluorophosphate 0 .25 ethyl- ( 2 , 2 -difluoroethyl ) carbonate + ( 0 . 5 ) fluoroethylene carbonate (31 . 5 :67 . 5 : 1 . 0 ) Example 74 ethylene carbonate + lithium difluorophosphate 0 . 28 83 So ethyl- ( 2 , 2 -difluoroethyl ) carbonate + ( 0 . 5 ) vinylene carbonate iiiiiiiiii (31 . 5 :67 . 5 : 1 . 0 ) US 9 ,853 , 326 B2 155 156 TABLE 8 Results of evaluation of high temperature storability Storage Residual Recovery Monofluorophosphate and / or swell capacity capacity Nonaqueous solvent (mass % ) difluorophosphate (mass % ) (mL ) ( % ) Comparative ethylene carbonate + 0 . 31 31 60 3 Example 13 diethyl carbonate ( 36 . 6 :63 . 4 ) Comparative ethylene carbonate + 0 . 38 Example 14 diethyl carbonate + august et fluoroethylene carbonate ( 36 . 3 :62 . 7 : 1 . 0 ) Comparative ethylene carbonate + lithium difluorophosphate 0 . 24 5 Example 15 diethyl carbonate ( 0 .5 ) ( 36 .6 :63 . 4 ) Comparative ethylene carbonate + 0 . 45 6 Example 16 diethyl carbonate + se vinylene carbonate (36 . 3 :62 . 7 : 1 . 0 ) Comparative ethylene carbonate + 0 .49 70 8 3 Example 17 diethyl carbonate + fluoroethylene carbonate + vinylene carbonate ( 35 . 9 :62 . 1 :10 : 1 . 0 ) Comparative ethylene carbonate + lithium difluorophosphate 0 . 38 sos Example 18 diethyl carbonate + ( 0 . 5 ) vinylene carbonate (36 . 3 :62 . 7 : 1 . 0 ) Comparative fluoroethylene carbonate + 0 .42 74 d Example 19 diethyl carbonate ( 39 . 7 :60 . 3 ) Comparative fluoroethylene carbonate + 0 .49 Example 20 diethyl carbonate + ados vinylene carbonate ( 39 . 3 :59 . 7 : 1 .0 ) Comparative ethylene carbonate + 0 . 35 68 e Example 21 diethyl carbonate + ethyl difluoroethyl carbonate ( 39 . 3 :59 . 7 : 1 . 0 ) tes Comparative ethylene carbonate + 0 .47 69 % Example 22 diethyl carbonate + ethyl difluoroethyl carbonate + vinylene carbonate ( 35 . 9 :62 . 1 : 1 . 0 : 1 . 0 ) Comparative ethylene carbonate + 00 .. 33 70 % Example 23 ethyl- ( 2 , 2 - difluoroethyl ) carbonate ( 31 . 8 :68 . 2 ) Comparative ethylene carbonate + 0 . 49 Example 24 ethyl- ( 2 , 2 - difluoroethyl ) carbonate + 0. 49 71 83 vinylene carbonate (31 . 5 :67 . 5 : 1 . 0 )

The following was ascertained as apparent from Table 6 tive Examples 13 and 16 for Nonaqueous Electrolyte 1 ) . The to Table 8 . Even in the case of using a negative -electrode same effect was observed also in the case of using nonaque active material containing silicon , which is a non - carbon 50 ous electrolytes containing vinylene carbonate , which is an material, the nonaqueous - electrolyte secondary batteries example of the specific carbonate . produced using the nonaqueous electrolytes 1 of the inven tion ( Example 56 of Nonaqueous Electrolyte 1 to Example Example 1 of Nonaqueous Electrolyte 2 74 of Nonaqueous Electrolyte 1 ) , which contained at least one carbonate having a halogen atom and further contained 55 < Production of Nonaqueous - Electrolyte Secondary Bat a monofluorophosphate and/ or a difluorophosphate , were tery > inhibited from swelling during high -temperature storage and [ Production of Positive Electrode ] from deteriorating in battery characteristics represented by A positive electrode was produced in the same manner as residual capacity and recovery capacity as in the case of in [ Production of Positive Electrode ] in Example 1 of using a carbon material as an active material, as compared 60 Nonaqueous Electrolyte 1 . with the nonaqueous -electrolyte secondary batteries pro - [ Production of Negative Electrode ] duced using the nonaqueous electrolytes containing one of A negative electrode was produced in the same manner as these compounds (Comparative Example 14 for Nonaque - in [Production of Negative Electrode ] in Example 1 of ous Electrolyte 1 , Comparative Example 15 for Nonaqueous Nonaqueous Electrolyte 1 . Electrolyte 1 , and Comparative Examples 17 to 24 for 65 [Nonaqueous Electrolyte ] Nonaqueous Electrolyte 1 ) or using the nonaqueous elec - In a dry argon atmosphere , LiPF , which each had been trolytes containing neither of those compounds ( Compara - sufficiently dried was dissolved , in an amount of 1 mol/ L , in US 9 , 853, 326 B2 157 158 a nonaqueous solvent prepared by mixing ethylene carbon Example 2 of Nonaqueous Electrolyte 2 to ate (EC ) , ethyl methyl carbonate (EMC ) , and dimethoxy Example 10 of Nonaqueous Electrolyte 2 and ethane (DME ), which is “ a compound which is liquid at 25° Comparative Example 4 for Nonaqueous C ., has a permittivity of 5 or higher and a coefficient of Electrolyte 2 viscosity of 0 . 6 cP or lower , and has a group constituting a 5 heteroelement- containing framework (excluding carbonyl Desired nonaqueous electrolytes were prepared in the group )" , in the proportion shown in Table 9 . Thus , a non - samemanner as in Example 1 of Nonaqueous Electrolyte 2 , aqueous electrolyte was prepared . Furthermore , a monofluo except that the kinds and contents of the nonaqueous solvent rophosphate and /or a difluorophosphate was dissolved in the and the monofluorophosphate and /or difluorophosphate solution so as to result in the respective concentrations were changed to those shown in Table 9 . Nonaqueous shown in Table 9 . Thus , a desired nonaqueous electrolyte electrolyte secondary batteries were produced and then was obtained . evaluated for high - temperature storability in the same man [ Fabrication of Nonaqueous - Electrolyte Secondary Battery ] ner as in Example 1 of Nonaqueous Electrolyte 2 . The | A battery was produced in the same manner as in [ Fab - 15 results thereof are shown in Table 9 . rication of Nonaqueous- Electrolyte Secondary Battery ] in Example 1 of Nonaqueous Electrolyte 1. Comparative Example 1 for Nonaqueous < Evaluation of Nonaqueous- Electrolyte Secondary Battery Electrolyte 2 for Nonaqueous Electrolyte 2 to for High - Temperature Storability > Comparative Example 3 for Nonaqueous The battery in a sheet form was evaluated in the state of Electrolyte 2 being sandwiched between glass plates in order to enhance contact between the electrodes . At 25° C ., this battery was Desired nonaqueous electrolytes were prepared in the subjected to 3 cycles of charge/ discharge at a constant samemanner as in Example 1 of Nonaqueous Electrolyte 2 , current corresponding to 0 . 2 C and at a final charge voltage 25 except that the nonaqueous solvent only was used so as to of 4 .2V and a final discharge voltage of 3V to stabilize the result in the contents shown in Table 9 . Nonaqueous battery . In the fourth cycle , the battery was subjected to 4 . 2V electrolyte secondary batteries were produced and then constant- current constant- voltage charge (CCCV charge ) evaluated for high - temperature storability in the sameman ( 0 . 05 C cutting ) in which the battery was charged to a final z ner as in Example 1 of Nonaqueous Electrolyte 2 . The charge voltage of 4 .2V at a current corresponding to 0 . 5 Cc 30 results thereof are shown in Table 9 . and further charged until the charge current value reached a current value corresponding to 0 .05 C . Thereafter , this Example 11 of Nonaqueous Electrolyte 2 to battery was subjected to 3V discharge at a constant current Example 12 of Nonaqueous Electrolyte 2 and corresponding to 0 . 2 C to determine the discharge capacity 35 Comparative Example 5 for Nonaqueous of the battery before high - temperature storage. This battery Electrolyte 2 to Comparative Example 7 for was subjected again to 4 .2V -CCCV (0 .05 C cutting ) charge Nonaqueous Electrolyte 2 and then stored at a high temperature under the conditions of Desired nonaqueous electrolytes were prepared in the 85° C . and 24 hours. 40 same manner as in Example 1 of Nonaqueous Electrolyte 2 , Before and after the high - temperature storage , the sheet except that the nonaqueous solvent was used so as to result battery was immersed in an ethanol bath . The amount of the in the contents shown in Table 9 and that vinylene carbonate gas evolved was determined from the resultant volume (VC ) was used in an amount of 1 % by mass based on the change . This gas amount was taken as “ storage swell (mL ) " . whole nonaqueous electrolyte . Nonaqueous - electrolyte sec The battery which had undergone the storage was discharged 45 ondary batteries were produced and then evaluated for at 25° C . and a constant current of 0 . 2 C to a final discharge high - temperature storability in the same manner as in voltage of 3V to obtain the “ residual capacity ( % ) ” after the Example 1 of Nonaqueous Electrolyte 2 . The results thereof storage test. This battery was subjected again to 4 . 2V -CCCV are shown in Table 9 . ( 0 .05 C cutting ) charge and then discharged to 3V at a The symbols used for expressing nonaqueous solvents in current value corresponding to 0 . 2 C to determine the 0 . 2 C 30 Table 9 and the permittivities and viscosity coefficients capacity and thereby obtain the 0 . 2 C capacity of the battery thereof are as follows. which had undergone the storage test . This capacity was EC : ethylene carbonate (permittivity , 90 ; viscosity coeffi taken as “ recovery capacity ( % )” . This battery was subjected cient, 1 .9 ) once more to 4 .2V - CCCV (0 .05 C cutting ) charge and then 55 EMC : ethyl methyl carbonate (permittivity , 2 .9 ; viscosity discharged to 3V at a current value corresponding to 1 C to coefficient, 0 . 7 ) determine the 0 . 2 C capacity and thereby obtain the 1 C DME: dimethoxyethane (permittivity , 7 . 1 ; viscosity coeffi capacity of the battery which had undergone the storage test. cient, 0 . 5 ) This capacity was divided by the 0 . 2 C capacity , and the EME: ethoxymethoxyethane (permittivity , 5 . 7 ; viscosity resultant quotient was taken as “ load characteristics ( % )” . 60 coefficient, 0 . 5 ) In Table 9 are shown the storage swell (mL ) , the residual DEE : diethoxyethane (permittivity , 5 ; viscosity coefficient , capacity ( % ) and recovery capacity ( % ) , which are values 0 .6 ) when the discharge capacity before the high - temperature AN : acetonitrile ( permittivity , 37. 5 ; viscosity coefficient, storage is taken as 100 , and the load characteristics (% ). “ 1 65 0 . 4 ) C ” means a current value at which the battery can be fully PN : propionitrile (permittivity , 27 .7 ; viscosity coefficient , charged by 1 -hour charge . 0 . 4 ) US 9 ,853 , 326 B2 159 160 TABLE 9 Monofluorophosphate Addition of Results of evaluation of high - temperature storability Nonaqueous and / or vinylene Storage Residual Recovery Load solvent difluorophosphate carbonate swell capacity capacity characteristics No. ( vol % ) (mass % ) ( 1 mass % ) (mL ) ( % ) Example 1 EC : EMC :DME = lithium not added 0 . 20 68 73 0 30 : 60 : 10 difluorophosphate ( 0 . 5 ) EC : EMC : DME = lithium not added 0 .28 0 30 : 60 : 10 difluorophosphate (0 . 1 ) Example 3 EC : EMC :DME = lithium not added 0 .16 3 30 :60 : 10 difluorophosphate ( 1 . 0 ) Example 4 EC : EMC : DME = dilithium not added 0 . 33 6 30 : 60 : 10 monofluorophosphate ( 0 . 1 ) ExExample 5 EC : EMC : EME = lithium not added 0 . 16 9 30 : 60 : 10 difluorophosphate (0 .5 ) Example 6 EC : EMC :DEE = lithium not added 0 . 16 30 :60 : 10 difluorophosphate (0 .5 ) Example 7 EC : EMC :DME = lithium not added 0 . 15 8 30 :65 : 5 difluorophosphate (0 .5 ) Example 8 EC :EMC : AN = lithium not added 0 .25 8 30 :65 : 5 difluorophosphate (0 . 5 ) Example 9 EC :EMC :AN = lithium not added 0 .30 8 30 :60 : 10 difluorophosphate ( 0 .5 ) Example 10 EC : EMC :PN = lithium not added 0 . 23 8 30 :65 :5 difluorophosphate (0 . 5 ) Example 11 EC : EMC : DME = lithium added 0 . 24 8 30 :60 : 10 difluorophosphate (0 . 5 ) Example 12 EC :EMC :AN = lithium added 0 . 28 8 30 :65 : 5 difluorophosphate ( 0 . 5 ) Comparative EC : EMC = 30 :70 none not added 0. 18 8 Example 1 Comparative EC : EMC: DME = none not added Unable to be did not did not did not Example 2 30 :60 : 10 measured work work work Comparative EC :EMC : AN = none not added Unable to be did not did not did not Example 3 30 :65 :5 measured work work work Comparative EC : EMC = 30 : 70 lithium not added 0 . 20 67 78 68 Example 4 difluorophosphate (0 .5 ) Comparative EC :EMC = 30 :70 none added 0 . 37 75 85 Example 5 Comparative EC :EMC : DME = none added 3 . 2 43 52 Example 6 30 :60 :10 Comparative EC :EMC :AN = none added 3 . 6 25 32 Example 7 30 :65 :5 Minh

The following is apparent from Table 9 . The nonaqueous - 40 trolytes produced in Comparative Example 1 for Nonaque electrolyte secondary batteries produced using the nonaque - ous Electrolyte 2 and Comparative Example 4 for Nonaque ous electrolytes of the invention , which contained a “ com - ous Electrolyte 2 , which contained a difluorophosphate only . pound which was liquid at 25° C . , had a permittivity of 5 or Furthermore, these nonaqueous electrolytes according to the higher and a coefficient of viscosity of 0 .6 cP or lower , and 45 invention were equal to or lower than these comparative had a group constituting a heteroelement- containing frame nonaqueous electrolytes in the deterioration of battery char work (excluding carbonyl group ) ” according to this inven - acteristics. The nonaqueous electrolytes of the invention , on tion and further contained a monofluorophosphate and/ or a the other hand, enabled the batteries to retain high load difluorophosphate , were inhibited from swelling during characteristics , which show an advantage inherent in the high - temperature storage beyond the range where battery 50 " compound which is liquid at 25° C ., has a permittivity of operation was possible and were further inhibited from 5 or higher and a coefficient of viscosity of 0 . 6 cP or lower , deteriorating in battery characteristics represented by and has a group constituting a heteroelement - containing residual capacity and recovery capacity , as compared with framework ( excluding carbonyl group ) ” according to the the nonaqueous - electrolyte secondary batteries produced invention . The batteries of Comparative Example 2 for using the nonaqueous electrolytes containing one of those 55 Nonaqueous Electrolyte 2 and Comparative Example 3 for compounds or containing neither of those compounds, while Nonaqueous Electrolyte 2 , in which a “ compound which retaining the advantage of keeping resistance low , which was liquid at 25° C . , had a permittivity of 5 or higher and a advantage is inherent in the " compound which is liquid at coefficient of viscosity of 0 .6 CP or lower , and had a group 25° C ., has a permittivity of 5 or higher and a coefficient of constituting a heteroelement- containing framework (exclud viscosity of 0 . 6 cP or lower, and has a group constituting a 60 ing carbonyl group ) " only was contained , deteriorated to heteroelement- containing framework ( excluding carbonyl such a degree that the batteries did not work . The difference group ) " . The batteries according to the invention , on the between the batteries of the Examples and those of the other hand , retained high load characteristics. Comparative Examples is clear. Specifically , the nonaqueous electrolytes produced in Furthermore , as apparent from Comparative Example 6 Example 1 of Nonaqueous Electrolyte 2 to Example 10 of 65 for Nonaqueous Electrolyte 2 to Comparative Example 7 for Nonaqueous Electrolyte 2 compared favorably in swelling Nonaqueous Electrolyte 2 , the batteries, in which the non during high -temperature storage with the nonaqueous elec aqueous electrolytes contained vinylene carbonate (VC ) as US 9 ,853 , 326 B2 161 162 an example of the specific carbonate , continued working in Example 1 of Nonaqueous Electrolyte 3 a certain degree. However , a comparison between these Comparative Examples and Example 1 of Nonaqueous < Production of Nonaqueous -Electrolyte Secondary Bat Electrolyte 2 to Example 10 of Nonaqueous Electrolyte 2 tery > shows that there is a large difference in load characteristics. 5 [Production of Negative Electrode ] This is because the coexistence of the three ingredients, i. e . , Ninety - four parts by weight of a natural- graphite powder a “ compound which is liquid at 25° C . , has a permittivity of having a d value for the lattice plane (002 ) and a crystallite 5 or higher and a coefficient of viscosity of 0 . 6 cP or lower , size (Lc ) , both determined by X - ray diffractometry , of 0 .336 and has a group constituting a heteroelement - containing nm and 652 nm , respectively, an ash content of 0 .07 parts by framework ( excluding carbonyl group )” , a difluorophosophos- 10 weight, a median diameter as determined by the laser diffraction / scattering method of 12 um , a specific surface phoric acid , and vinylene carbonate , produced a further area as determined by the BET method of 7 . 5 m / g , an R effect as in Example 11 of Nonaqueous Electrolyte 2 and value ( IPL ) as determined by Raman spectroscopy using Example 12 of Nonaqueous Electrolyte 2 . an argon ion laser light of 0 . 12 , and a half -value width for 15 a peak in 1 ,570 - 1 ,620 cm - range of 19. 9 cm - 2 was mixed Examples of Nonaqueous Electrolyte 3 and with 6 parts by weight of poly (vinylidene fluoride ) . Comparative Examples for Nonaqueous Electrolyte N -Methyl - 2 -pyrrolidone was added to the mixture to slurry 3 it . This slurry was evenly applied to one side of a copper foil having a thickness of 12 um and dried . Thereafter, the coated 20 foil was pressed so as to result in a negative - electrode The nonaqueous - electrolyte secondary batteries obtained active- material layer having a density of 1 .67 g/ cm3. Thus, in the following Examples of Nonaqueous Electrolyte 3 and a negative electrode was obtained . Comparative Examples for Nonaqueous Electrolyte 3 were [ Production of Positive Electrode ] evaluated by the methods shown below . Ninety percent by mass lithium cobalt oxide (LiCo02 ) as 25 a positive - electrode active material was mixed with 4 % by Each nonaqueous- electrolyte secondary battery was mass carbon black and 6 % by mass poly ( vinylidene fluo ride) (trade name “ KF - 1000 ” , manufactured by Kureha evaluated in the state of being sandwiched between glass Chemical) . N -Methyl - 2 -pyrrolidone was added to the mix plates in order to enhance contact between the electrodes . At ture to slurry it . This slurry was applied to each side of an 25° C ., this battery was charged to 4 .2V at a constant current\ 30 aluminum foil having a thickness of 15 um and dried . corresponding to 0 .2 C and then discharged to 3V at a Thereafter, the coated foil was pressed so as to result in constant current of 0 . 2 C . Three cycles of this charge ! positive - electrode active -material layers having a density of discharge were conducted to stabilize the battery . In the 32 g /cm3 Thus a positive electrode was obtained fourth cycle , the battery was charged to 4 . 2V at a constant [Nonaqueous Electrolyte ] current of 0 .5 C , subsequently charged at a constant voltage 35 In a dry argon atmosphere , sufficiently dried LiPF , and of 4 . 2V until the current value reached 0 . 05 C , and then vinylene carbonate were added , in concentrations of 1 mol/ L discharged to 3V at a constant current of 0 . 2 C to determine and 2 % by mass respectively , to a mixture of ethylene initial discharge capacity . “ 1 C ” means a current value at carbonate , ethyl methyl carbonate , and dimethyl carbonate which the reference capacity of the battery is discharged (volume ratio , 2 : 4 :4 ). The monofluorophosphate and /or dif over 1 hour; “ 0 . 2 C ” means the current value which is 1 /5 the 40 luorophosphate and the compound A of the invention ” were 1 C . dissolved therein so as to result in the respective concen trations shown in Table 10 . Thus, a desired nonaqueous < Evaluation of Continuous -Charge Characteristics > electrolyte was obtained . The nonaqueous - electrolyte secondary battery which had [ Production of Nonaqueous - Electrolyte Secondary Battery ] undergone the capacity evaluation test was immersed in an 45 The positive electrode and negative electrode described ethanol bath to measure the volume thereof. Thereafter, at above and a separator made of polyethylene were super 60° C ., the battery was subjected to constant- current charge posed in the order of negative electrode/ separator/ positive at a constant current of 0 . 5 C and , at the time when the electrode /separator / negative electrode to produce a battery voltage had reached 4 .25V , the constant - current charge was element. This battery element was inserted into a bag changed to constant- voltage charge to conduct continuous 50 constituted of a laminated film obtained by coating both charge for 1 week . This battery was cooled and then sides of aluminum ( thickness , 40 um ) with a resin layer , with immersed in an ethanol bath to measure the volume thereof. terminals of the positive and negative electrodes projecting The amount of the gas which had generated was determined outward . Thereafter, the nonaqueous electrolyte was intro from the volume change through the continuous charge . This duced into the bag , and this bag was vacuum - sealed to gas amount was taken as " amount of gas evolved through 55 produce a sheet battery . This battery was subjected to the continuous charge (mL ) ” . After the determination of the evaluation of continuous -charge characteristics described amount of the gas evolved , the battery was discharged to 3V above . The results thereof are shown in Table 10 . at 25° C . and a constant current of 0 . 2 C . Subsequently , this battery was charged to 4 .2V at a constant current of 0 .5 C , Example 2 of Nonaqueous Electrolyte 3 to thereafter charged at a constant voltage of 4 . 2V until the 60 Example 10 of Nonaqueous Electrolyte 3 and current value reached 0 .05 C , and then discharged to 3V at Comparative Example 1 for Nonaqueous a constant current of 1 C to determine the 1 C discharge Electrolyte 3 to Comparative Example 4 for capacity of the battery which had undergone the continuous Nonaqueous Electrolyte 3 charge test . The proportion of this 1 C discharge capacity after the continuous -charge test to the initial discharge 65 Desired nonaqueous electrolytes were prepared in the capacity was determined , and this proportion was taken as same manner as in Example 1 of Nonaqueous Electrolyte 3 , " 1 C discharge capacity after continuous charge ( % )” . except that the “ monofluorophosphate and /or difluorophos US 9 ,853 , 326 B2 163 164 phate ” and “ compound of the invention ” shown in Table 10 subsequently charged at a constant voltage of 4 .2V until the were replaced with the kinds shown in Table 10 and used so current value reached 0. 05 C , and then discharged to 3V at as to result in the contents shown in Table 10 . Nonaqueous a constant current of 0 . 2 C to determine initial discharge electrolyte secondary batteries were produced and then capacity . “ 1 C ” means a current value at which the reference evaluated for continuous - charge characteristics in the same 5 capacity of the battery is discharged over 1 -hour ; “ 2 C ” manner as in Example 1 of Nonaqueous Electrolyte 3 . The means the current value two times the 1 C and “ 0 . 2 C ” results thereof are shown in Table 10 . means the current value which is 1 /5 the 1 C . TABLE 10 Amount of gas 1C discharge evolved through capacity after Monofluorophosphate and / or Compound of the invention continuous continuous NoNo. difluorophosphate (mass % ) (mass % ) charge (mL ) charge ( % ) Example 1 Lithium difluorophosphate ethyl diethylphosphinate 0 . 39 ( 0 . 5 ) ( 0 . 5 ) Example 2 Lithium difluorophosphate Succinonitrile 0 .36 (0 . 5 ) ( 0 . 5 ) Example 3 Lithium difluorophosphate methyl isocyanate 0 . 45 $9 ( 0 . 5 ) ( 0 . 5 ) Example 4 Lithium difluorophosphate Hexafluorotricyclophosphazene 0 . 39 ( 0 . 5 ) ( 0 . 5 ) Example 5 Lithium difluorophosphate 1 , 4 -butanediolbis ( 2 , 2 , 2 0 . 40 ( 0 . 5 ) trifluoroethanesulfonate ) ( 0 . 5 ) Example 6 Lithium difluorophosphate di- n -butyl sulfide 0 .44 ( 0 . 5 ) ( 0 . 2 ) Example 7 Lithium difluorophosphate di- n - butyl disulfide 0 .43 ( 0 . 5 ) ( 0 . 2 ) Example 8 Lithium difluorophosphate Succinic anhydride 0 . 41 ( 0 . 5 ) ( 0 . 3 ) Example 9 Lithium difluorophosphate a -methyl - y -butyrolactone 0 .42 ( 0 . 5 ) ( 0 . 5 ) Example 10 Lithium difluorophosphate 2 - propynyl acetate 0 . 44 ( 0 . 5 ) ( 0 . 5 ) Comparative – 0 .53 Example 1 Comparative Lithium difluorophosphate 0 .51 Example 2 (0 . 5 ) Comparative – ethyl diethylphosphinate 0 . 54 Example 3 ( 0 . 5 ) Comparative — Succinonitrile 0 .40 Example 4 ( 0 . 5 )

The following is apparent from Table 10 . The nonaque - 40 [Evaluation of 2 C Discharge Capacity ] ous- electrolyte secondary batteries produced using the non The battery which had undergone the test for evaluating aqueous electrolytes of the invention , which contained a initial discharge capacity was subjected at 25° C . to a test in " compound A of the invention ” and further contained a which the battery was charged to 4 .2V at a constant current monofluorophosphate and /or difluorophosphate (Example 1 of 0 . 5 C , subsequently charged at a constant voltage of 4 . 2V of Nonaqueous Electrolyte 3 to Example 10 of Nonaqueous 45 until the current value reached 0 .05 C , and discharged to 3V Electrolyte 3 ) , were inhibited from suffering gas evolution at a constant current of 2 C . The proportion of the resultant and battery characteristics deterioration during continuous discharge capacity ( % ) to the discharge capacity determined charge as compared with the nonaqueous - electrolyte sec - through the test for initial discharge capacity, which was ondary batteries produced using the nonaqueous electrolytes taken as 100 , was determined . containing one of those compounds (Comparative Example 50 [Evaluation of High - Temperature Storability ] 2 for Nonaqueous Electrolyte 3 to Comparative Example 4 The battery which had undergone the capacity evaluation for Nonaqueous Electrolyte 3 ) or using the nonaqueous tests was charged to 4 . 2V at a constant current of 0 . 5 C and electrolyte containing neither of those compounds (Com - then charged at a constant voltage of 4 .2V until the current parative Example 1 for Nonaqueous Electrolyte 3 ) . value reached 0 .05 C . This battery was stored at 85° C . for The batteries obtained in the following Examples of 55 24 hours and then cooled . Thereafter , this battery was Nonaqueous Electrolyte 4 and Comparative Examples for subjected at 25° C . to a test in which the battery was Nonaqueous Electrolyte 4 were evaluated by the methods discharged to 3V at a constant current of 0 . 2 C , charged to shown below . 4 . 2V at a constant current of 0 . 5 C , subsequently charged at [Evaluation of Initial Discharge Capacity ] a constant voltage of 4 .2V until the current value reached Each lithium secondary battery was evaluated in the state 60 0 .05 C , and then discharged to 3V at a constant current of 2 of being sandwiched between glass plates in order to C . The proportion of the resultant discharge capacity ( % ) to enhance contact between the electrodes. At 25° C ., this the discharge capacity determined through the test for initial battery was charged to 4 .2V at a constant current corre - discharge capacity , which was taken as 100 , was determined . sponding to 0 . 2 C and then discharged to 3V at a constant [Evaluation of Thermal Stability ] current of 0 .2 C . Three cycles of this charge /discharge were 65 The battery was charged to 4 . 2V at a constant current conducted to stabilize the battery . In the fourth cycle , the corresponding to 0 . 2 C and then discharged to 3V at a battery was charged to 4 .2V at a constant current of 0 .5 C constant current of 0 .2 C . Three cycles of this charge / US 9 ,853 , 326 B2 165 166 discharge were conducted to stabilize the battery. In the (VEC ) was used in place of the vinylene carbonate (VC ) in fourth cycle, the battery was charged to 4 .2V at a constant the electrolyte of Example 1 of Nonaqueous Electrolyte 4 . current of 0 . 5 C and then charged at a constant voltage of The components of the electrolyte and the results of the 4 . 2V until the current value reached 0 .05 C . The quantity of evaluation are shown in Table 11 and Table 12 . exothermic heat of this battery in a charged state was 5 measured with a Calvet calorimeter over the range of from Example 3 of Nonaqueous Electrolyte 4 room temperature to 300° C . A sheet - form lithium secondary battery was produced and Example 1 of Nonaqueous Electrolyte 4 evaluated in the same manners as in Example 1 of Non 10 aqueous Electrolyte 4 , except that fluoroethylene carbonate [ Production of Negative Electrode ] (FEC ) was used in place of the vinylene carbonate (VC ) in To 98 parts by weight of artificial -graphite powder KS - 44 the electrolyte of Example 1 of Nonaqueous Electrolyte 4 . ( trade name; manufactured by Timcal) were added 100 parts by weight of an aqueous dispersion of sodium carboxym The components of the electrolyte and the results of the ethyl cellulose ( concentration of sodium carboxymethyl 15 evaluation are shown in Table 11 and Table 12. cellulose , 1 % by mass ) as a thickener and 2 parts by weight Example 4 of Nonaqueous Electrolyte 4 of an aqueous dispersion of a styrene /butadiene rubber ( concentration of styrene/ butadiene rubber, 50 % by mass ) as a binder . The ingredients were mixed together by means of A sheet- form lithium secondary battery was produced and a disperser to obtain a slurry . The slurry obtained was 20 evaluated in the same manners as in Example 1 of Non applied to one side of a copper foil having a thickness of 10 aqueous Electrolyte 4 , except that 0 .5 parts by weight of um and dried . This coated foil was rolled with a pressing LiPO F2 was used in place of the vinylene carbonate (VC ) machine to a thickness of 75 um , and a piece of a shape in the electrolyte of Example 1 of Nonaqueous Electrolyte 4 . having an active -material laver size with a width of 30 mm The components of the electrolyte and the results of the and a length of 40 mm and having an uncoated area with a 25 evaluation are shown in Table 11 and Table 12 . width of 5 mm and a length of 9 mm was cut out of the rolled sheet . Thus, a negative electrode was obtained . Comparative Example 1 for Nonaqueous [ Production of Positive Electrode ] Electrolyte 4 Ninety percent by mass lithium cobalt oxide (LiC002 ) as a positive - electrode active material was mixed with 5 % by 30 A sheet - form lithium secondary battery was produced and mass acetylene black as a conductive material and 5 % by evaluated in the same manners as in Example 1 of Non mass poly ( vinylidene fluoride ) ( PVDF ) as a binder in aqueous Electrolyte 4 , except that use was made of an N -methylpyrrolidone solvent to obtain a slurry . The slurry electrolyte produced by dissolving sufficiently dried Lipfa obtained was applied to one side of an aluminum foil having in a mixture of sulfolane ( SLF) and ethyl methyl carbonate a thickness of 15 uma and dried . This coated foil was rolled 35 ( EMC ) (volume ratio , 3 : 7 ) so as to result in a proportion of with a pressing machine to a thickness of 80 um , and a piece 1 .0 mol/ L . The components of the electrolyte and the results of a shape having an active -material layer size with a width of the evaluation are shown in Table 11 and Table 12 . of 30 mm and a length of 40 mm and having a uncoated area with a width of 5 mm and a length of 9 mm was cut out of Comparative Example 2 for Nonaqueous the rolled sheet . Thus, a positive electrode was obtained . 40 Electrolyte 4 [ Production of Electrolyte ] In a dry argon atmosphere, 98 parts by weight of a mixture A sheet- form lithium secondary battery was produced and of sulfolane (SLF ) and ethyl methyl carbonate (EMC ; coef ficient of viscosity at 25° C . , 0 .68 mPa. s ) ( volume ratio , 3 : 7 ) evaluated in the same manners as in Example 1 of Non was mixed with 2 parts by weight of vinylene carbonate 45 aqueous Electrolyte 4 , except that use was made of an (VC ) . Subsequently , sufficiently dried LiPF6 was dissolved electrolyte produced by mixing 94 parts by weight of a therein so as to result in a proportion of 1 . 0 mol/ L . Thus, an mixture of sulfolane ( SLF ) and y -butyrolactone (GBL ; coef electrolyte was obtained . ficient of viscosity at 25° C . , 1 . 73 mPa . s ) (volume ratio , 3 : 7 ) [ Production of Nonaqueous -Electrolyte Battery ] with 2 parts by weight of vinylene carbonate (VC ) , 2 parts The positive electrode and negative electrode described 50 by weight of vinylethylene carbonate (VEC ) , and 2 parts by above and a separator made of polyethylene were super weight of trioctyl phosphate ( TOP ) and then dissolving posed in the order of negative electrode/ separator/ positive sufficiently dried LiPF , therein so as to result in a proportion electrode to produce a battery element . This battery element of 1 . 0 mol/ L . The components of the electrolyte and the was inserted into a bag constituted of a laminated film results of the evaluation are shown in Table 11 and Table 12 . obtained by coating both sides of aluminum ( thickness , 40 55 um ) with a resin layer , with terminals of the positive and Comparative Example 3 for Nonaqueous negative electrodes projecting outward . Thereafter, the elec Electrolyte 4 trolyte was introduced into the bag , and this bag was vacuum -sealed to produce a sheet battery . This battery was A sheet - form lithium secondary battery was produced and evaluated . The components of the electrolyte and the results 60 evaluated in the same manners as in Example 1 of Non of the evaluation are shown in Table 11 and Table 12 . aqueous Electrolyte 4 , except that use was made of an electrolyte produced by mixing 94 parts by weight of a Example 2 of Nonaqueous Electrolyte 4 mixture of sulfolane (SLF ) and y- butyrolactone (GBL ) ( vol ume ratio , 3 : 7 ) with 2 parts by weight of vinylene carbonate A sheet- form lithium secondary battery was produced and 65 (VC ) , 2 parts by weight of vinylethylene carbonate (VEC ) , evaluated in the same manners as in Example 1 of Non - and 2 parts by weight of trioctyl phosphate ( TOP) and then aqueous Electrolyte 4 , except that vinylethylene carbonate dissolving sufficiently dried LiBF4 therein so as to result in US 9 ,853 , 326 B2 167 168 a proportion of 1 . 0 mol / L . The components of the electrolyte trolyte obtained by the samemethods as in Example 3 of and the results of the evaluation are shown in Table 11 and Nonaqueous Electrolyte 4 . This battery was evaluated for Table 12 . thermal stability by thermal analysis . The results of the Comparative Example 4 for Nonaqueous evaluation are shown in Table 13 . Electrolyte 4 Comparative Example 6 for Nonaqueous Electrolyte 4 A sheet - form lithium secondary battery was produced and evaluated in the same manners as in Example 1 of Non A sheet- form lithium secondary battery was produced aqueous Electrolyte 4 , except that use was made of an 10 using the positive electrode , negative electrode , and elec electrolyte produced by mixing 98 parts by weight of a trolyte obtained by the same methods as in Comparative mixture of y -butyrolactone (GBL ) and ethyl methyl carbon - Example 4 for Nonaqueous Electrolyte 4 . This battery was ate ( EMC ) (volume ratio , 3 :7 ) with 2 parts by weight of evaluated for thermal stability by thermal analysis . The vinylene carbonate (VC ) and then dissolving sufficiently results of the evaluation are shown in Table 13. dried LiPF , therein so as to result in a proportion of 1 . 0 13 mol/ L . The components of the electrolyte and the results of TABLE 13 the evaluation are shown in Table 11 and Table 12 . Quantity of exothermic heat Comparative Example 5 for Nonaqueous ( 1) 20 Electrolyte 4 Example 5 382 Comparative Example 6 605 A sheet - form lithium secondary battery was produced and evaluated in the same manners as in Example 1 of Non aqueous Electrolyte 4 , except that use was made of an The following was found as apparent from Table 11 to electrolyte produced by mixing 98 parts by weight of a 25 Table 13 . The batteries employing the nonaqueous electro mixture of ethylene carbonate (EC ) and ethyl methyl car lytes according to the invention (Examples 1 to 4 of Non bonate ( EMC ) ( volume ratio , 3 : 7 ) with 2 parts by weight of aqueous Electrolyte 4 ) were excellent in high - current - den vinylene carbonate (VC ) and then dissolving sufficiently sity charge/ discharge characteristics and high -temperature dried LiPF , therein so as to result in a proportion of 1 . 0 storability and further had high safety as can be seen from mol/ L . The components of the electrolyte and the results of 30 the small quantity of exothermic heat of the battery of Example 5 of Nonaqueous Electrolyte 4 . On the other hand , the evaluation are shown in Table 11 and Table 12 . the batteries employing the nonaqueous electrolytes which were not nonaqueous electrolytes of the invention (Com TABLE 11 parative Example 1 for Nonaqueous Electrolyte to Com Electrolyte Solvent 35 parative Example 5 for Nonaqueous Electrolyte 4 ) were inferior in charge /discharge characteristics and high - tem Example 1 LiPF6 SLF + EMC + VC Example 2 LiPF SLF + EMC + VEC perature storability and had a large quantity of exothermic Example 3 LiPF SLF + EMC + FEC heat as in Comparative Example 6 for Nonaqueous Electro Example 4 LiPF SLF + EMC + LiPO F2 lyte 4 . Comparative Example 1 LiPF6 SLF + EMC Comparative Example 2 LiPF SLF + GBL + VC + VEC + TOP 40 [Production of Positive Electrode ] Comparative Example 3 LiBF4aaa SLF + GBL + VC + VEC + TOP Ninety - two parts by weight of a lithium -transition metal Comparative Example 4 LiPF6 GBL + EMC + VC composite oxide containing nickel, manganese, and cobalt Comparative Example 5 LiPF6 EC + EMC + VC (LiNi . . 33Mno .33C00 . 3302 ) was mixed with 4 parts by weight of poly ( vinylidene fluoride ) (hereinafter suitably referred to 45 as “ PVdF % ) and 4 parts by weight of acetylene black . N -Methylpyrrolidone was added to the mixture to slurry it . TABLE 12 This slurry was applied to each side of a current collector 2 C discharge capacity 2C discharge capacity made of aluminum , and dried . Thus, a positive electrode was before 85° C . storage ( % ) after 85° C . storage ( % ) obtained . Example 1 83. 1 82 . 6 50 [Production of Negative Electrode ] Example 2 82 . 5 81. 8 Ninety - two parts by weight of a graphite powder was Example 3 87 .4 80 . 8 mixed with 8 parts by weight of PVdF . N -Methylpyrrolidone Example 4 89 . 7 85 . 5 Comparative 66 . 1 55 . 4 was added to the mixture to slurry it . This slurry was applied Example 1 to one side of a current collector made of copper , and dried . Comparative 48 . 3 3 . 4 55 Thus, a negative electrode was obtained . Example 2 [Production of Nonaqueous- Electrolyte Secondary Battery ] Comparative 14 .1 Example 3 26. 0 The positive electrode and negative electrode described Comparative 89 . 8 70. 2 above and a separator made of polyethylene were super Example 4 posed in the order of negative electrode / separator/ positive Comparative 89. 1 84 . 7 60 electrode / separator /negative electrode . The battery element Example 5 thus obtained was wrapped in a cylindrical aluminum laminated film . The electrolyte which will be described later was introduced into this package , which was then vacuum Example 5 of Nonaqueous Electrolyte 4 sealed . Thus , a sheet- form nonaqueous - electrolyte second 65 ary battery was produced . Furthermore, this sheet battery A sheet- form lithium secondary battery was produced was pressed by being sandwiched between glass plates, in using the positive electrode, negative electrode , and elec order to enhance contact between the electrodes . US 9 ,853 , 326 B2 169 170 [ Capacity Evaluation ] Example 3 of Nonaqueous Electrolyte 5 In a 25° C . thermostatic chamber , the sheet - form non aqueous - electrolyte secondary battery was subjected to con - A nonaqueous electrolyte was prepared by adding 1 , 4 , 8 , stant- current constant- voltage charge (hereinafter suitably 11- tetraazacyclotetradecane and lithium difluorophosphate referred to as “ CCCV charge ” ) to 4 .4V at 0 . 2 C and then 5 (LiPO , F , ) to the base electrolyte ( I ) so as to result in discharged to 2 .75 V at 0 . 2 C . This operation was repeated concentrations of 0 . 1 % by mass and 0 . 5 % by mass , respec three times to conduct conditioning . Thereafter, this battery tively , based on the nonaqueous electrolyte . Using this was subjected again to CCCV charge to 4 .4V at 0 .2 C and nonaqueous electrolyte , a nonaqueous - electrolyte secondary discharged again to 2 .75 V at 1 C to determine initial discharge capacity. The cutoff current in each charging 10 battery was produced by the method described above . This operation was set at 0 .05 C . Incidentally , “ 1 C ” means a battery was subjected to the capacity evaluation and the current value at which the whole capacity of the battery is evaluation of 4 . 4V continuous - charge characteristics . The discharged over 1 hour. results thereof are shown in Table 14 . [ Evaluation of 4 .4V Continuous - Charge Characteristics Example 4 of Nonaqueous Electrolyte 5 The battery which had undergone the capacity evaluation 15 test was placed in a 60° C . thermostatic chamber and A nonaqueous electrolyte was prepared by adding 1 ,4 , 8 , subjected to constant- current charge at 0 . 2 C . At the time 11 - tetraazacyclotetradecane to the base electrolyte ( I) so as when the voltage had reached 4 . 4V , the constant- current to result in a concentration of 0 . 02 % by mass based on the charge was changed to constant- voltage charge . The battery nonaqueous electrolyte . Using the nonaqueous electrolyte was charged for 14 days and then cooled to 25° C . Subse - 20 obtained , a nonaqueous - electrolyte secondary battery was quently , this battery was immersed in an ethanol bath to produced by the method described above . This battery was measure the buoyancy (Archimedes ' principle ) , and the subjected to the capacity evaluation and the evaluation of amount of the gas evolved was determined from the buoy ancy. Furthermore , the degree of deterioration in capacity 4 . 4V continuous - charge characteristics . The results thereof through the continuous charge was evaluated in the follow - 25 are shown in Table 14 . ing manner. The battery was first discharged to 3V at 0 . 2 C , Example 5 of Nonaqueous Electrolyte 5 subsequently subjected to CCCV charge to 4 . 4V at 0 . 2 C , and then discharged to 2 . 75 V at 1 C to measure the A nonaqueous electrolyte was prepared by adding 1 , 4 , 8 , discharge capacity ( recovery capacity ) in this discharge . The 11 - tetraazacyclotetradecane to the base electrolyte ( I ) so as capacity retention after the continuous charge was deter - 30 to result in a concentration of 0 . 05 % by mass based on the mined according to the following calculation equation . The nonaqueous electrolyte . Using this nonaqueous electrolyte , a larger the value of this property , the lower the deterioration nonaqueous - electrolyte secondary battery was produced by of the battery . the method described above . This battery was subjected to Capacity retention after continuous 7 -day charge the capacity evaluation and the evaluation of 4 .4V continu ( % ) = [ ( recovery capacity after continuous 7 -day 35 ous - charge characteristics. The results thereof are shown in charge )/ (initial discharge capacity ) ]x100 Table 14 . Example 1 of Nonaqueous Electrolyte 5 Example 6 of Nonaqueous Electrolyte 5 LiPF , as an electrolyte was dissolved , in a proportion of 40 A nonaqueous electrolyte was prepared by adding 1 , 4 , 8 , 1 mol/ L , in a mixed solvent composed of ethylene carbonate 11 - tetraazacyclotetradecane to the base electrolyte ( I ) so as ( EC ) as a cyclic carbonate and ethyl methyl carbonate to result in a concentration of 0 . 1 % by mass based on the ( EMC ) as an acyclic carbonate (mixing volume ratio , 2 : 8 ; nonaqueous electrolyte . Using this nonaqueous electrolyte , a weight ratio , 24 .7 : 75 . 3 ) . This solution is referred to as base nonaqueous -electrolyte secondary battery was produced by electrolyte (I ). A nonaqueous electrolyte was prepared by 45 the method described above. This battery was subjected to adding 1 , 4 , 8 , 11 - tetraazacyclotetradecane and vinylene car - the capacity evaluation and the evaluation of 4 . 4V continu bonate ( VC ) to the base electrolyte ( 1) so as to result in ous -charge characteristics . The results thereof are shown in concentrations of 0 . 1 % by mass and 1 % by mass , respec - Table 14 . tively , based on the nonaqueous electrolyte . Using this nonaqueous electrolyte , a nonaqueous - electrolyte secondary 50 Example 7 of Nonaqueous Electrolyte 5 battery was produced by the method described above . This battery was subjected to the capacity evaluation and the A nonaqueous electrolyte was prepared by adding 1 , 4 , 7 , evaluation of 4 .4V continuous -charge characteristics . The 10 -tetraazacyclododecane to the base electrolyte ( I ) so as to resultsre thereof are shown in Table 14 . result in a concentration of 0 . 1 % by mass based on the 55 nonaqueous electrolyte . Using this nonaqueous electrolyte , a Example 2 of Nonaqueous Electrolyte 5 nonaqueous- electrolyte secondary battery was produced by the method described above . This battery was subjected to A nonaqueous electrolyte was prepared by adding 1, 4 ,8 , the capacity evaluation and the evaluation of 4 .4V continu 11 - tetraazacyclotetradecane and fluoroethylene carbonate ous -charge characteristics . The results thereof are shown in ( FEC ) to the base electrolyte ( I ) so as to result in concen - 60 Table 14 . trations of 0 . 1 % by mass and 1 % by mass , respectively , based on the nonaqueous electrolyte . Using this nonaqueous Example 8 of Nonaqueous Electrolyte 5 electrolyte , a nonaqueous -electrolyte secondary battery was produced by the method described above . This battery was A nonaqueous electrolyte was prepared by adding 1 , 4 , 8 , subjected to the capacity evaluation and the evaluation of 65 11 -tetramethyl -1 , 4 ,8 , 11 - tetraazacyclotetradecane to the base 4 .4V continuous - charge characteristics . The results thereof electrolyte ( 1 ) so as to result in a concentration of 0 . 1 % by are shown in Table 14 . mass based on the nonaqueous electrolyte . Using this non US 9 ,853 , 326 B2 171 172 aqueous electrolyte , a nonaqueous - electrolyte secondary (EC ) as a cyclic carbonate and ethyl methyl carbonate battery was produced by the method described above . This ( EMC ) as an acyclic carbonate (mixing volume ratio , 3 : 7 ; battery was subjected to the capacity evaluation and the weight ratio , 36 . 0 :64 . 0 ) . This solution is referred to as base evaluation of 4 .4V continuous - charge characteristics. The electrolyte ( IV ) . A nonaqueous electrolyte was prepared by results thereof are shown in Table 14 . 5 adding 1 , 4 , 8 , 11 - tetraazacyclotetradecane to the base elec Example 9 of Nonaqueous Electrolyte 5 trolyte ( IV ) so as to result in a concentration of 0 .1 % by mass based on the nonaqueous electrolyte . Using the non A nonaqueous electrolyte was prepared by adding 1, 4, 8 , aqueous electrolyte obtained , a nonaqueous - electrolyte sec 11 - tetraazacyclotetradecane -5 , 7 -dione to the base electro ondary battery was produced by the method described lyte ( I ) so as to result in a concentration of 0 . 1 % by mass " above . This battery was subjected to the capacity evaluation based on the nonaqueous electrolyte . Using this nonaqueous and the evaluation of 4 . 4V continuous - charge characteris electrolyte , a nonaqueous - electrolyte secondary battery was tics . The results thereof are shown in Table 14 . produced by the method described above . This battery was subjected to the capacity evaluation and the evaluation of Example 14 of Nonaqueous Electrolyte 5 4 . 4V continuous - charge characteristics . The results thereof 15 are shown in Table 14 . LiPF , as an electrolyte was dissolved , in a proportion of 1 mol/ L , in a mixed solvent composed of ethylene carbonate Example 10 of Nonaqueous Electrolyte 5 ( EC ) as a cyclic carbonate and ethyl methyl carbonate ( EMC ) as an acyclic carbonate (mixing volume ratio , 4 : 6 ; A nonaqueous electrolyte was prepared by adding cyclo 20 weight ratio , 46 .7 :53 .4 ). This solution is referred to as base ( B - alanylglycyl- ß - alanylglycyl) to the base electrolyte ( I ) so electrolyte ( V ) . A nonaqueous electrolyte was prepared by as to result in a concentration of 0 .02 % by mass based on the adding 1 , 4 , 8 , 11 - tetraazacyclotetradecane - 5 , 7 - dione to the nonaqueous electrolyte . Using this nonaqueous electrolyte, a base electrolyte ( V ) so as to result in a concentration of 0 . 1 % nonaqueous - electrolyte secondary battery was produced by by mass based on the nonaqueous electrolyte . Using the the method described above . This battery was subjected to 25 nonaqueous electrolyte obtained , a nonaqueous -electrolyte the capacity evaluation and the evaluation of 4 .4V continu - secondary battery was produced by the method described ous- charge characteristics. The results thereof are shown in above . This battery was subjected to the capacity evaluation Table 14 . and the evaluation of 4 .4V continuous- charge characteris tics . The results thereof are shown in Table 14 . Example 11 of Nonaqueous Electrolyte 5 30 Example 15 of Nonaqueous Electrolyte 5 LiPF , as an electrolyte was dissolved , in a proportion of 1 mol/ L , in a mixed solvent composed of ethylene carbonate LiPF , as an electrolyte was dissolved , in a proportion of ( EC ) as a cyclic carbonate and ethyl methyl carbonate 1 mol/ L , in a mixed solvent composed of ethylene carbonate ( EMC ) as an acyclic carbonate (mixing volume ratio , 1: 9; 35 (EC ) and propylene carbonate (PC ) as cyclic carbonates weight ratio , 12 . 7 : 87 . 3 ) . This solution is referred to as base (mixing volume ratio , 5 : 5 ; weight ratio , 52 . 4 : 47 . 6 ) . This electrolyte ( II ) . A nonaqueous electrolyte was prepared by solution is referred to as base electrolyte (VI ) . A nonaqueous adding 1 , 4 , 8 , 11 - tetraazacyclotetradecane to the base elec electrolyte was prepared by adding 1 , 4 , 8 , 11 -tetraazacyclo trolyte ( II) so as to result in a concentration of 0 . 1 % by mass tetradecane - 5 , 7 - dione to the base electrolyte (VI ) so as to based on the nonaqueous electrolyte . Using the nonaqueous 40 result in a concentration of 0 . 1 % by mass based on the electrolyte obtained , a nonaqueous - electrolyte secondary nonaqueous electrolyte. Using the nonaqueous electrolyte battery was produced by the method described above . This obtained , a nonaqueous - electrolyte secondary battery was battery was subjected to the capacity evaluation and the produced by the method described above . This battery was evaluation of 4 . 4V continuous - charge characteristics . The subjected to the capacity evaluation and the evaluation of results thereof are shown in Table 14 . 45 4 .4V continuous- charge characteristics . The results thereof are shown in Table 14 . It can be seen that when a cyclic Example 12 of Nonaqueous Electrolyte 5 polyamide compound has been added , there is no limitation on the weight ratio of cyclic carbonates usable as solvents . LiPF as an electrolyte was dissolved , in a proportion of 1 mol/ L , in a mixed solvent composed of fluoroethylene 50 Comparative Example 1 for Nonaqueous carbonate (FEC ) as a cyclic carbonate and ethyl methyl Electrolyte 5 carbonate (EMC ) as an acyclic carbonate (mixing volume ratio , 1: 9 ; weight ratio , 14 .2 :85 .8 ). This solution is referred Using the base electrolyte (I ) by itself, a nonaqueous to as base electrolyte ( III) . A nonaqueous electrolyte was electrolyte secondary battery was produced by the method prepared by adding 1, 4 ,8 ,11 - tetraazacyclotetradecane to the 55 described above . This battery was subjected to the capacity base electrolyte (III ) so as to result in a concentration of evaluation and the evaluation of 4 .4V continuous -charge 0 .1 % by mass based on the nonaqueous electrolyte . Using characteristics. The results thereof are shown in Table 14 . the nonaqueous electrolyte obtained , a nonaqueous -electro lyte secondary battery was produced by the method Comparative Example 2 for Nonaqueous described above . This battery was subjected to the capacity 60 Electrolyte 5 evaluation and the evaluation of 4 . 4V continuous - charge characteristics . The results thereof are shown in Table 14 . LiPF as an electrolyte was dissolved , in a proportion of 1 mol/ L , in a mixed solvent composed of ethylene carbonate Example 13 of Nonaqueous Electrolyte 5 ( EC ) as a cyclic carbonate and ethyl methyl carbonate 65 (EMC ) as an acyclic carbonate (mixing volume ratio , 35 :65 ; LiPF , as an electrolyte was dissolved , in a proportion of weight ratio , 41 . 4 :58 . 6 ) . This solution is referred to as base 1 mol/ L , in a mixed solvent composed of ethylene carbonate electrolyte (VII ) . A nonaqueous electrolyte was prepared by US 9 ,853 , 326 B2 173 174 adding 1, 4 ,8 , 11- tetraazacyclotetradecane to the base elec The symbols each used for expressing a cyclic polyamine trolyte (VII ) so as to result in a concentration of 0 . 1 % by compound or cyclic polyamide compound in Table 14 are as mass based on the nonaqueous electrolyte . Using the non - follows. aqueous electrolyte obtained , a nonaqueous -electrolyte sec cyclam : 1, 4 ,8 ,11 - tetraazacyclotetradecane ondary battery was produced by the method described 5 cyclen : 1 , 4 , 7 , 10 - tetraazacyclododecane above . This battery was subjected to the capacity evaluation TM - cyclam : 1 , 4 , 8 , 11- tetramethyl- 1 , 4 , 8 , 11- tetraazacyclo and the evaluation of 4 .4V continuous -charge characteris tetradecane tics. The results thereof are shown in Table 14 . DO - cyclam : 1 , 4 , 8 ,11 - tetraazacyclotetradecane - 5 , 7 - dione TetO - cyclam : cyclo ( ß - alanylglycyl- B -alanylglycyl ) Comparative Example 3 for Nonaqueous 10 In Table 14 , the “ specific compound ” means “ at least one Electrolyte 5 compound selected from the group consisting of unsaturated carbonates , fluorine -containing carbonates, monofluoro LiPF , as an electrolyte was dissolved , in a proportion of phosphates , and difluorophosphates ” . The symbols used for 1 mol/ L , in a mixed solvent composed of ethylene carbonate expressing “ specific compounds ” are as follows. (EC ) as a cyclic carbonate and ethyl methyl carbonate 15 VC : vinylene carbonate ( EMC ) as an acyclic carbonate (mixing volume ratio , 4 : 6 ; FEC : fluoroethylene carbonate weight ratio , 46 .7 : 53 .4 ). This solution is referred to as base LiPO Fz: lithium difluorophosphate electrolyte ( V ) . A nonaqueous electrolyte was prepared by The following is apparent from Table 14 . Use of the nonaqueous electrolytes according to the invention adding 1 , 4 , 8 , 11- tetraazacyclotetradecane to the base elec 20 improved continuous - charge characteristics (Examples 1 to trolyte ( V ) so as to result in a concentration of 0 . 1 % by mass 15 of Nonaqueous Electrolyte 5 ) . On the other hand , in the based on the nonaqueous electrolyte . Using the nonaqueous case of the nonaqueous electrolytes which were not non electrolyte obtained , a nonaqueous - electrolyte secondary aqueous electrolytes according to the invention (i . e . , in the battery was produced by the method described above. This case of the nonaqueous electrolytes falling under none of battery was subjected to the capacity evaluation and the 25 embodiment 5 - 1, embodiment 5 - 2 , and embodiment 5 -3 ), evaluation of 4 . 4V continuous - charge characteristics . The the batteries were inferior in continuous - charge character results thereof are shown in Table 14 . istics ( Comparative Examples 1 to 3 for Nonaqueous Elec TABLE 14 Cyclic polyamineine Specific compound or compound After continuous cyclic polyamide (mass % charge test compound (mass % based on Nonaqueous Nonaqueous Gas Capacity based on nonaqueous nonaqueous organic solvent organic solvent amount retention No . electrolyte ) electrolyte ) ( volume ratio ) (mass ratio ) (mL ) ( % ) Example 1 cyclam 0 . 1 % VC 1 % EC / EMC = EC / EMC = 0 . 32 65 . 6 2 / 8 24 . 7 / 75 . 3 Example 2 cyclam 0 . 1 % FEC 1 % EC / EMC = EC / EMC = 0 .33 67 . 5 2 / 8 24 . 7 / 75 . 3 Example 3 cyclam 0 .1 % LiPO F2 EC / EMC = EC / EMC = 0 .19 70 . 6 0 . 5 % 2 / 8 24 . 7 / 75 . 3 ExampleEx 4 cyclam 0 .02 % none EC / EMC = EC /EMC = 0 . 24 63 . 8 2 / 8 24 . 7 / 75 . 3 Example 5 cyclam 0 .05 % none EC / EMC = EC /EMC = 0 .23 65 . 0 2 / 8 24 . 7 / 75 . 3 Example 6 cyclam 0 .1 % none EC / EMC = EC / EMC = 0 .28 61. 9 2 / 8 24 . 7 / 75 . 3 Example 7 cyclen 0. 1 % none EC / EMC = EC / EMC = 0 .27 55 . 6 2 / 8 24 . 7 / 75 . 3 Example 8 TM -cyclam 0. 1 % none EC / EMC = EC / EMC = 0 . 18 53 . 8 2 / 8 24 . 7 / 75 . 3 Example 9 DO -cyclam 0. 1 % none EC / EMC = EC /EMC = 0 . 28 64. 4 2 / 8 24 . 7 /75 . 3 Example 10 TetO - cyclam 0 .02 % none EC /EMC = EC /EMC = 0 . 22 65. 0 2 / 8 24 . 7 /75 . 3 Example 11 cyclam 0 . 1 % none EC / EMC = EC / EMC = 0 . 20 61 . 3 1 / 9 12. 7 /87 . 3 Example 12 cyclam 0 . 1 % FEC / EMC = FEC /EMC = 0 . 32 66. 3 none 1 / 9 14 . 2 /85 . 8 Example 13 cyclam 0 . 1 % none EC / EMC = EC / EMC = 0 . 35 60 .0 3 / 7 36 . 0 /64 . 0 Example 14 DO -cyclam 0 . 1 % none EC / EMC = EC / EMC = 0 . 35 56 . 9 4 / 6 46 . 7 /53 . 4 Example 15 DO -cyclam 0 . 1 % none EC / PC = EC /PC = 0 . 39 59 . 4 5 / 5 52 . 4 /47 . 6 Comparative none none EC / EMC = EC / EMC = 0 . 82 43 . 8 Example 1 2 / 8 24 . 7 / 75 . 3 Comparative cyclam 0 . 1 % none EC / EMC = EC / EMC = 0 .71 48 . 1 ExExample 2 35 /65 41. 4 /58 . 6 Comparative cyclam 0. 1 % none EC / EMC = EC / EMC = 0 .. 9898 40 . 6 Example 3 4 / 6 46 . 7 /53 . 4 US 9 ,853 , 326 B2 175 176 trolyte 5 ) . Furthermore , in the case of the nonaqueous where the discharge capacity as measured before the high organic solvents which contained a cyclic polyamine com - temperature storage is taken as 100 are shown in Table 15 . pound and further contained a cyclic carbonate in an amount exceeding 40 % by mass as in Comparative Example 2 for Example 2 of Nonaqueous Electrolyte 6 Nonaqueous Electrolyte 5 and Comparative Example 3 for 5 Nonaqueous Electrolyte 5 , the batteries had poor continu A nonaqueous - electrolyte secondary battery was pro ous - charge characteristics . duced in the same manner as in Example 1 of Nonaqueous < Production of Secondary Battery > Electrolyte 6 , except that the lithium salt of cyclic 1, 2 [Production of Positive Electrode] perfluoroethanedisulfonylimide, which is a cyclic disulfo A positive electrode was produced in the same manner as 10 nylimide salt , was used in an amount of 0 . 1 mol/ L . This in [ Production of Positive Electrode ] in Example 1 of battery was evaluated , and the results thereof are shown in Nonaqueous Electrolyte 1 . Table 15 . [ Production of Negative Electrode ] A negative electrode was produced in the same manner as 15 Example 3 of Nonaqueous Electrolyte 6 in [Production of Negative Electrode ] in Example 1 of Nonaqueous Electrolyte 1 . A nonaqueous- electrolyte secondary battery was pro duced in the same manner as in Example 1 of Nonaqueous Nonaqueous Electrolyte Electrolyte 6 , except that the lithium salt of cyclic 1 , 2 perfluoroethanedisulfonylimide , which is a cyclic disulfo Example 1 of Nonaqueous Electrolyte 6 nylimide salt , was used in an amount of 0 . 01 mol/ L . This battery was evaluated , and the results thereof are shown in One mol/ L LiPF , 0 .05 mol/ L lithium salt of cyclic Table 15 . 1 , 2 -perfluoroethanedisulfonylimide , which is the cyclic dis ulfonylimide salt shown in Table 15 , and 0 . 5 % by mass 25 Example 4 of Nonaqueous Electrolyte 6 lithium difluorophosphate which each had been sufficiently dried were dissolved in a mixture of ethylene carbonate and A nonaqueous -electrolyte secondary battery was pro ethyl methyl carbonate ( volume ratio , 3 : 7 ) in a dry argon duced in the same manner as in Example 1 of Nonaqueous atmosphere . Thus , a desired nonaqueous electrolyte was Electrolyte 6 , except that the lithium salt of cyclic 1 , 2 obtained . 30 perfluoroethanedisulfonylimide, which is a cyclic disulfo [ Fabrication of Battery ] nylimide salt, was used in an amount of 0 .05 mol/ L . This A battery was produced in the same manner as in [ Fab - battery was evaluated , and the results thereof are shown in rication of Battery ] in Example 1 of Nonaqueous Electrolyte Table 15 . [ Evaluation of Battery ] 35 Example 5 of Nonaqueous Electrolyte 6 The battery in a sheet form was evaluated in the state of being sandwiched between glass plates in order to enhance A nonaqueous- electrolyte secondary battery was pro contact between the electrodes . At 25° C . , this battery was duced in the same manner as in Example 1 of Nonaqueous subjected to 3 cycles of charge / discharge at a constant Electrolyte 6 , except that the sodium salt of cyclic 1 , 2 current corresponding to 0 . 2 C and at a final charge voltage 40 perfluoroethanedisulfonylimide , which is a cyclic disulfo of 4 .2V and a final discharge voltage of 3V to stabilize the nylimide salt , was used in an amount of 0 .05 mol/ L . This battery . In the fourth cycle , the battery was subjected to 4 . 4V battery was evaluated , and the results thereof are shown in constant -current constant - voltage charge (CCCV charge ) Table 15 ( 0 . 05 C cutting ) in which the battery was charged to a final charge voltage of 4 . 4V at a current corresponding to 0 . 5 C 45 Example 6 of Nonaqueous Electrolyte 6 and further charged until the charge current value reached a current value corresponding to 0 .05 C . Thereafter, this A nonaqueous- electrolyte secondary battery was pro battery was subjected to 3V discharge at a constant current duced in the same manner as in Example 1 of Nonaqueous corresponding to 0 . 2 C to determine the discharge capacity Electrolyte 6 , except that lithium difluorophosphate was of the battery before high -temperature storage . This battery 50 used in an amount of 0 . 1 % by mass. This battery was was subjected again to 4 .4V -CCCV (0 .05 C cutting ) charge evaluated , and the results thereof are shown in Table 15 . and then stored at a high temperature under the conditions of 85° C . and 24 hours . Example 7 of Nonaqueous Electrolyte 6 Before and after the high - temperature storage , the sheet battery was immersed in an ethanol bath . The amount of the 55 A nonaqueous - electrolyte secondary battery was pro gas evolved was determined from the resultant volume duced in the same manner as in Example 1 of Nonaqueous change . The battery which had undergone the storage was Electrolyte 6 , except that lithium difluorophosphate was discharged at 25° C . and a constant current of 0 . 2 C to a final used in an amount of 1 . 0 % by mass. This battery was discharge voltage of 3V to obtain the residual capacity after evaluated , and the results thereof are shown in Table 15 . the storage test . This battery was subjected again to 4 . 4V - 60 CCCV ( 0 . 05 C cutting ) charge and then discharged to 3V at Example 8 of Nonaqueous Electrolyte 6 a current value corresponding to 0 . 2 C to determine the 0 . 2 C capacity and thereby obtain the 0 . 2 C capacity of the A nonaqueous- electrolyte secondary battery was pro battery which had undergone the storage test. This capacity duced in the same manner as in Example 1 ofNonaqueous was taken as recovery capacity . “ 1 C " means a current value 65 Electrolyte 6 , except that sodium difluorophosphate was at which the battery can be fully charged by 1 -hour charge . used in an amount of 0 . 5 % by mass . This battery was The residual capacity and recovery capacity ( % ) in the case evaluated , and the results thereof are shown in Table 15 . US 9 ,853 , 326 B2 177 178 Example 9 of Nonaqueous Electrolyte 6 Comparative Example 2 for Nonaqueous Electrolyte 6 A nonaqueous- electrolyte secondary battery was pro duced in the same manner as in Example 1 of Nonaqueous A nonaqueous - electrolyte secondary battery was pro Electrolyte 6 , except that lithium monofluorophosphate was 5 duced in the same manner as in Example 1 of Nonaqueous used in an amount of 0 . 5 % by mass. This battery was Electrolyte 6 , except that the 0 .5 % by mass lithium difluo evaluated , and the results thereof are shown in Table 15 . rophosphate was omitted . This battery was evaluated , and Example 10 of Nonaqueous Electrolyte 6 the results thereof are shown in Table 15 . 10 A nonaqueous- electrolyte secondary battery was pro Comparative Example 3 for Nonaqueous duced in the same manner as in Example 1 of Nonaqueous Electrolyte 6 Electrolyte 6 , except that a desired nonaqueous electrolyte was obtained by dissolving 1 mol/ L sufficiently dried LiPF6, A nonaqueous- electrolyte secondary battery was pro 0 .05 mol/ L lithium salt of cyclic 1 , 2 - perfloroethanedisulfo - 15 duced in the samemanner as in Example 1 of Nonaqueous nylimide, which is the cyclic disulfonylimide salt shown in Electrolyte 6 , except that the 0. 05 mol /L lithium salt of Table 15 , 0 . 5 % by mass lithium difluorophosphate , and 1 cyclic 1 , 2 -perfluoroethanedisulfonylimide , which is a cyclic part by weight of vinylene carbonate in a mixture of ethylene disulfonylimide salt, was omitted . This battery was evalu carbonate and ethyl methyl carbonate ( volume ratio , 3 : 7 ) in ated , and the results thereof are shown in Table 15 . a dry argon atmosphere . This battery was evaluated , and the 20 results thereof are shown in Table 15 . Comparative Example 4 for Nonaqueous Comparative Example 1 for Nonaqueous Electrolyte 6 Electrolyte 6 25 A nonaqueous -electrolyte secondary battery was pro A nonaqueous - electrolyte secondary battery was pro d uced in the same manner as in Example 1 of Nonaqueous duced in the samemanner as in Example 1 of Nonaqueous Electrolyte 6 , except that a nonaqueous electrolyte was Electrolyte 6 , except that a nonaqueous electrolyte was obtained by dissolving 1 mol/ L sufficiently dried LiPF , and obtained by dissolving 1 mol/ L sufficiently dried LiPF in a 1 part by weight of vinylene carbonate in a mixture of mixture of ethylene carbonate and ethyl methyl carbonate 30 ethylene carbonate and ethyl methyl carbonate ( volume ( volume ratio , 3 : 7 ) in a dry argon atmosphere . This battery ratio , 3 : 7 ) in a dry argon atmosphere . This battery was was evaluated , and the results thereof are shown in Table 15 . evaluated , and the results thereof are shown in Table 15 . TABLE 15 Results of evaluation of high Cyclic Monofluorophosphate Presence or temperature storability disulfonylimide and / or absence of Storage Residual Recovery salt difluorophosphate vinylene swell capacity capacity (mol / L ) ( wt % carbonate (mL ) ( % ) ( % ) Example 1 lithium salt of cyclic lithium absent 0 . 14 80 85 1 , 2 -perfloroethane - difluorophosphate disulfonylimide (0 .5 ) ( 0 . 05 ) Example 2 lithium salt of cyclic lithium absent 0 . 191983 1 , 2 - perfloroethane - difluorophosphate disulfonylimide ( 0 . 5 ) ( 0 . 1 ) Example 3 lithium salt of cyclic lithium absent 0 . 14 78 82 1 ,2 -perfloroethane - difluorophosphate disulfonylimide ( 0 . 5 ) liijiji ( 0 . 01 ) Example 4 lithium salt of cyclic lithium absent 0 . 15 81 85 1 , 2 -perfloropropane - difluorophosphate disulfonylimide ( 0 . 5 ) ( 0 . 05 ) Example 5 sodium salt of cyclic lithium absent 0 . 16 81 84 1 , 2 - perfloroethane - difluorophosphate disulfonylimide ( 0 . 5 ) ( 0 . 05 ) Example 6 lithium salt of cyclic lithium absent 0 . 17 75 81 1 , 2 -perfloroethane - difluorophosphate disulfonylimide ( 0 . 1 ) ( 0 .05 ) Example 7 lithium salt of cyclic lithium absent 0 . 13 %80 86 1 , 2 - perfloroethane - difluorophosphate disulfonylimide ( 1 . 0 ) ( 0 . 05 ) Example 8 lithium salt of cyclic sodium absent 0 . 16 %80 86 1 ,2 -perfloroethane - difluorophosphate disulfonylimide (0 . 5 ) ( 0 .05 ) US 9 ,853 , 326 B2 179 180 TABLE 15 - continued Results of evaluation of high Cyclic Monofluorophosphate Presence or temperature storability disulfonylimide and / or absence of Storage Residual Recovery salt difluorophosphatehate vinylene swell capacity capacity (mol / L ) (wt % carbonate (mL ) ( % ) ( % ) Example 9 lithium salt of cyclic dilithium absent 0 . 15 78 84 1 , 2 -perfloroethane - monofluorophosphate disulfonylimide (0 . 5 ) ( 0 . 05 ) Example 10 lithium salt of cyclic lithium present 0 .27 27 82 86 1 , 2 -perfloroethane - difluorophosphate disulfonylimide ( 0 . 5 ) ( 0 .05 ) Comparative absent 0 . 27 Example 1 Comparative lithium salt of cyclic — absent 0 . 33 Example 2 1 , 2 -perfloroethane disulfonylimide (0 . 05 ) Comparative — lithium absent 0 .20 20 67 Example 3 difluorophosphate (0 . 5 ) Comparative — present 0 .42 Example 4 0 . 42 67

The following is apparent from Table 15 . The nonaque - ing a high energy density can be produced in which the ous - electrolyte secondary batteries produced using the non - electrolytes are inhibited from decomposing and which are aqueous electrolytes of the invention , which contained at inhibited from deteriorating when used in a high -tempera least one cyclic disulfonylimide salt represented by general ture environment. These batteries further have high capacity formula ( 1 ) and further contained a monofluorophosphate 30 and are excellent in storability and cycle characteristics . and / or a difluorophosphate (Example 1 of Nonaqueous Consequently , these batteries are suitable for use in various Electrolyte 6 to Example 10 of Nonaqueous Electrolyte 6 ) , fields where nonaqueous -electrolyte secondary batteries are were inhibited from swelling during high - temperature stor used , e . g . , in the field of electronic appliances. age and from deteriorating in battery characteristics repre sented by residual capacity and recovery capacity , as com Nonaqueous Electrolyte 3 and pared with the nonaqueous - electrolyte secondary batteries Nonaqueous - Electrolyte Secondary Battery 3 produced using the nonaqueous electrolytes containing one of these compounds (Comparative Example 2 for Nonaque According to nonaqueous electrolyte 3 of the invention , a ous Electrolyte 6 and Comparative Example 3 for Nonaque - nonaqueous electrolyte and a nonaqueous- electrolyte sec ous Electrolyte 6 ) or using a nonaqueous electrolyte con - ondary battery can be produced which are excellent in cycle taining neither of those compounds (Comparative Example 40 characteristics , storability , inhibition of gas evolution during 1 for Nonaqueous Electrolyte 6 ) . continuous charge , and battery characteristics . Conse Furthermore , even when compared with Comparative quently , this battery is suitable for use in various fields Example 2 for Nonaqueous Electrolyte 6 and Comparative where nonaqueous - electrolyte secondary batteries are used , Example 3 for Nonaqueous Electrolyte 6 , in which the e . g . , in the field of electronic appliances . nonaqueous electrolytes contained only either of a cyclic 45 disulfonylimide salt represented by general formula ( 1 ) and Nonaqueous Electrolyte 4 and a monofluorophosphate and / or difluorophosphate , Example Nonaqueous- Electrolyte Secondary Battery 4 1 of Nonaqueous Electrolyte 6 to Example 10 of Nonaque ous Electrolyte 6 , in which the nonaqueous electrolytes Nonaqueous - electrolyte secondary battery 4 , which contained both of these compounds , were ascertained to 50 employs nonaqueous electrolyte 4 of the invention , retains have been improved in both inhibition of swelling during high capacity and is excellent in safety , etc . This battery can high - temperature storage and inhibition of deterioration in hence be used in various known applications . battery characteristics. In addition , as apparent from a com parison between Example 10 of Nonaqueous Electrolyte 6 Nonaqueous Electrolyte 5 and and Comparative Example 4 for Nonaqueous Electrolyte 6 , 55 Nonaqueous- Electrolyte Secondary Battery 5 the same effect was observed also in the case of using a nonaqueous electrolyte containing vinylene carbonate , Nonaqueous - electrolyte secondary battery 5 , which which is an example of the specific carbonate . employs nonaqueous electrolyte 5 of the invention , retains high capacity and is excellent in continuous- charge charac INDUSTRIAL APPLICABILITY 60 teristics , etc . This battery can hence be used in various known applications. Nonaqueous Electrolytes 1 and 2 and Nonaqueous -Electrolyte Secondary Batteries 1 and Nonaqueous Electrolyte 6 and Nonaqueous- Electrolyte Secondary Battery 6 65 According to nonaqueous electrolytes 1 and 2 of the According to nonaqueous electrolyte 6 of the invention , a invention , nonaqueous - electrolyte secondary batteries hav nonaqueous - electrolyte secondary battery having a high US 9 ,853 ,326 B2 181 182 energy density can be produced in which the nonaqueous Nonaqueous electrolyte 5 : Application No. 2007 -099274 electrolyte is inhibited from decomposing and which is ( filing date : Apr. 5 , 2007 ) inhibited from deteriorating when used in a high - tempera - Nonaqueous electrolyte 6 : Application No. 2007 - 111931 ture environment . This battery further has high capacity autaand ( filing date : Apr. 20 , 2007) is excellent in storability and cycle characteristics . Conse - 5 quently , this battery is suitable for use in various fields The invention claimed is : where nonaqueous -electrolyte secondary batteries are used , 1 . A nonaqueous electrolyte solution , comprising : e . g . , in the field of electronic appliances . ( 1 ) an electrolyte ; Applications of nonaqueous electrolytes 1 to 6 for sec ( 2 ) a nonaqueous solvent, which dissolves the electrolyte ondary batteries and nonaqueous- electrolyte secondary bat- 10 and comprises , based on a total volume of the non teries 1 to 6 of the invention are not particularly limited , and aqueous solvent: these electrolytes and batteries can be used in various known ( A ) from 5 -10 % by volume of at least one compound applications . Examples thereof include notebook personal selected from the group consisting of dimethoxy computers , pen - input personal computers, mobile personal ethane , diethoxyethane, and ethoxymethoxyethane ; computers , electronic -book players , portable telephones , 15 and portable facsimile telegraphs, portable copiers , portable ( B ) 90 % by volume or more of a cyclic carbonate and printers, headphone stereos, video movie cameras , liquid an acyclic carbonate ; and crystal TVs , handy cleaners , portable CD players , mini- disk ( 3 ) from 0 .001 - 5 % by mass , based on a total weight of the players , transceivers , electronic pocketbooks , electronic cal nonaqueous solvent, of LiPO ,F2 . culators , memory cards, portable tape recorders , radios, 20 , 2 . The nonaqueous electrolyte solution according to claim backup power sources, motors, motor vehicles, motorbikes , 20 1 , wherein the compound ( A ) is dimethoxyethane. bicycles fitted with a motor , bicycles , illuminators , toys , 3 . A nonaqueous- electrolyte secondary battery , compris game machines, clocks and watches, power tools , strobo ing : scopes, and cameras , and the like . a negative electrode and a positive electrode, which are This application is based on the following Japanese patent 35 capable of occluding/ releasing lithium ions ; and applications, the entire contents thereof being herein incor the nonaqueous electrolyte solution according to claim 1 . porated as a disclosure of the description of the invention . 4 . The nonaqueous - electrolyte secondary battery accord Nonaqueous electrolyte 1 : Application No . 2007 -116442 ing to claim 3 , wherein the negative electrode comprises a ( filing date : Apr. 26 , 2007 ) carbonaceous material. Nonaqueous electrolyte 2 : Application No. 2007 - 116445 30 5 . The nonaqueous- electrolyte secondary battery accord ( filing date : Apr . 26 , 2007 ) 30 ing to claim 3, wherein the negative electrode comprises a Nonaqueous electrolyte 3 : Application No . 2007 -116450 negative -electrode active material comprising at least one ( filing date : Apr. 26 , 2007 ) selected from the group consisting of a silicon atom , a tin Nonaqueous electrolyte 4 : Application No . 2007 - 111961 atom , and a lead atom . ( filing date : Apr. 20 , 2007 ) * * * * *