US008932761 B2

(12) United States Patent (10) Patent No.: US 8,932,761 B2 Yamaguchi et al. (45) Date of Patent: *Jan. 13, 2015

(54) ANODE AND METHOD OF HOIM 4/1.31 (2010.01) MANUFACTURING THE SAME, AND HO1 M 4/134 (2010.01) BATTERY AND METHOD OF HOIM IO/O52 (2010.01) MANUFACTURING THE SAME (52) U.S. Cl. (75) Inventors: Hiroyuki Yamaguchi, Fukushima (JP); CPC H0IM 4/38 (2013.01); H0IM 4/13 (2013.01); H01 M 4/139 (2013.01); H0IM 4/366 Hiroshi Horiuchi, Fukushima (JP): (2013.01); H0IM 4/485 (2013.01); HOIM Kenichi Kawase, Fukushima (JP); 4/131 (2013.01); H01 M 4/134 (2013.01): HOIM Tadahiko Kubota, Fukushima (JP); 10/052 (2013.01); Y02E 60/122 (2013.01) Hideki Nakai, Fukushima (JP); USPC ...... 429/231.1; 429/233 Takakazu Hirose, Fukushima (JP) (58) Field of Classification Search (73) Assignee: Sony Corporation, Tokyo (JP) USPC ...... 429/218.1, 209, 233,236, 242, 221, 429/223, 229, 220; 204/291, 290.01 (*) Notice: Subject to any disclaimer, the term of this See application file for complete search history. patent is extended or adjusted under 35 U.S.C. 154(b) by 937 days. (56) References Cited This patent is Subject to a terminal dis U.S. PATENT DOCUMENTS claimer. 4,950,566 A 8/1990 Huggins et al. (21) Appl. No.: 11/995,802 5,696,206 A * 12/1997 Chen et al...... 525, 186 (22) PCT Filed: May 22, 2007 2004/009 1780 A1* 5/2004 Kinoshita et al...... 429,231.1 (86). PCT No.: PCT/UP2007/060401 FOREIGN PATENT DOCUMENTS S371 (c)(1), JP 59-157969 * 9, 1984 ...... HOM 10/12 (2), (4) Date: Jan. 15, 2008 JP 08-333603 * 12, 1996 ...... B22F1/OO (87) PCT Pub. No.: WO2007/136046 (Continued) OTHER PUBLICATIONS PCT Pub. Date: Nov. 29, 2007 (65) Prior Publication Data International Search Report dated Oct. 7, 2007. US 2009/0092892 A1 Apr. 9, 2009 Primary Examiner — Raymond Alejandro (74) Attorney, Agent, or Firm — Dentons US LLP (30) Foreign Application Priority Data (57) ABSTRACT May 23, 2006 (JP) ...... 2006-142977 An anode wherein the anode active material layer includes May 23, 2006 (JP) ...... 2006-142978 anode active material particles made of an anode active mate May 11, 2007 (JP) ...... 2007-127005 rial including at least one of and tin as an element. An May 11, 2007 (JP) ...... 2007-127006 oxide-containing film including an oxide of at least one kind (51) Int. Cl. selected from the group consisting of silicon, germanium and HOLM 4/58 (2010.01) tin is formed in a region in contact with an electrolytic solu HOLM 4/38 (2006.01) tion of the surface of each anode active material particle. The HOLM 4/13 (2010.01) region in contact with the electrolytic solution of the surface HOLM 4/39 (2010.01) of each anode active material particle is covered with the HOLM 4/36 (2006.01) oxide-containing film. HOLM 4/485 (2010.01) 8 Claims, 8 Drawing Sheets

a- 22B, 34B

22D, 34D 220, 34C

22A, 34A US 8,932,761 B2 Page 2

(56) References Cited JP 2004-171874 6, 2004 JP 2004-319469 11, 2004 JP 2005-26144 * 1 2005 ...... HO1M 12/06 FOREIGN PATENT DOCUMENTS JP 2005-317446 11, 2005 WO 2006/033358 3, 2006 JP 09-28902O * 11, 1997 ...... HO1 M 4/62 JP 2000-012018 1, 2000 * cited by examiner U.S. Patent Jan. 13, 2015 Sheet 1 of 8 US 8,932,761 B2

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U.S. Patent Jan. 13, 2015 Sheet 8 of 8 US 8,932,761 B2

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300 295 290 285 ENERGY (eV)

FG. 9 US 8,932,761 B2 1. 2 ANODE AND METHOD OF coating film formed by a vapor-phase method, thereby suffi MANUFACTURING THE SAME, AND cient cycle characteristics cannot be obtained, so a further BATTERY AND METHOD OF improvement is desired. MANUFACTURING THE SAME In view of the foregoing, it is an object of the invention to provide an anode capable of improving charge-discharge effi TECHNICAL FIELD ciency and a method of manufacturing the anode, and a bat tery using the anode, and a method of manufacturing the The present invention relates to an anode including an battery. anode active material which includes at least one of silicon A first anode according to the invention is used in a battery 10 including a cathode, an anode and an electrolyte, and the (Si) and tin (Sn) as an element, and a method of manufactur anode includes: an anode current collector; and an anode ing the anode, and a battery and a method of manufacturing active material layer arranged on the anode current collector, the battery. wherein the anode active material layer includes anode active BACKGROUND ART material particles including at least one of silicon and tin as an 15 element, and each of the anode active material particles includes an oxide-containing film including an oxide of at In recent years, a large number of portable electronic least one kind selected from the group consisting of silicon, devices such as camcorders, digital still cameras, cellular germanium and tin in a region in contact with the electrolyte phones, personal digital assistances and laptop computers of its surface. In this case, the oxide-containing film is formed have been emerged, and an attempt to reduce the size and the by a liquid-phase method. weight of them has been made. Accordingly, the development A method of manufacturing an anode according to the oflightweight secondary batteries capable of obtaining a high invention is a method of manufacturing an anode used in a energy density as power sources for the electronic devices battery including a cathode, an anode and an electrolyte, and have been promoted. Among them, a lithium- secondary the method includes: a step of arranging an anode active battery using a carbon material for an anode, a composite 25 material layer including anode active material particles on an material of lithium (Li) and a transition metal for a cathode anode current collector, the anode active material particles and a carbonate for an electrolytic solution has been widely including at least one of silicon and tin; and a step of forming put to practical use, because the lithium-ion secondary battery an oxide-containing film including an oxide of at least one can obtain a larger energy density thana -acid battery and kind selected from silicon, germanium and tin in a region in a nickel-cadmium battery in related arts. 30 contact with the electrolyte of the surface of each of the anode Moreover, recently as the performance of portable elec active material particles by a liquid-phase method. tronic devices is enhanced, a further improvement in capacity A first battery according to the invention includes a cath is desired, and it is considered to use tin, silicon or the like as ode, an anode and an electrolyte, and the anode is the above an anode active material instead of a carbon material (for described anode according to the invention. Moreover, in a 35 method of manufacturing a battery according to the invention, example, refer to Patent Literature 1). It is because the theo an anode is manufactured by the above-described method of retical capacity of tin, 994 mAh/g, and the theoretical capac manufacturing an anode according to the invention. ity of silicon, 4199 mAh/g are much larger than the theoretical In the first anode and the first battery according to the capacity of graphite, 372 mAh/g, so an increase in capacity invention, the oxide-containing film is formed in a region in can be expected. 40 contact with the electrolyte of the surface of each anode active However, a tin alloy or a silicon alloy into which lithium is material particle by a liquid-phase method, so the region in inserted has high activity, so there is an issue that an electro contact with the electrolyte of the surface of each anode active lytic Solution is easily decomposed, and lithium is inacti material particle can be uniformly covered with the oxide vated. Therefore, when charge and discharge are repeated, containing film, and chemical stability can be improved. charge-discharge efficiency declines, thereby sufficient cycle 45 Therefore, in the battery using the anode, charge-discharge characteristics cannot be obtained. efficiency can be improved. Therefore, it is considered to form an inert layer on a In the method of manufacturing an anode and the method Surface of an anode active material, and, for example, it is of manufacturing a battery according to the invention, the proposed to form a coating film of silicon oxide on a Surface oxide-containing film is formed by a liquid-phase method, so of an anode active material (for example, refer to Patent 50 the oxide-containing film can be formed in the interior, which Literature 2). On the other hand, it is considered that when the cannot be not covered with the oxide-containing film by a thickness of the coating film of silicon oxide is increased, vapor-phase method, of the anode active material layer, and reaction resistance is increased, thereby cycle characteristics the anode according to the invention can be easily manufac become insufficient (for example, refer to Patent Literature tured. 3). In the past. Such a coating film of silicon oxide is formed 55 A second anode according to the invention includes: an by air oxidation or a vapor-phase method. anode current collector; and an anode active material layer Patent Literature 1 U.S. Pat. No. 4,950,566 arranged on the anode current collector, wherein the anode Patent Literature 2 Japanese Unexamined Patent Applica active material layer includes an anode active material includ tion Publication No. 2004-171874 ing at least one of silicon and tin as an element, and the anode Patent Literature 3 Japanese Unexamined Patent Applica 60 active material includes a coating film including an oxide of at tion Publication No. 2004-319469 least one kind selected from the group consisting of silicon, germanium (Ge) and tin and a halide of at least one kind DISCLOSURE OF THE INVENTION selected from the group consisting of silicon, germanium and tin on at least a part of its Surface. However, there are an issue that properties of a coating film 65 A second battery according to the invention includes a formed by air oxidation are poor and an issue that anode cathode, an anode and an electrolyte, wherein the anode active material particles are not sufficiently covered with a includes an anode current collector and an anode active mate US 8,932,761 B2 3 4 rial layer arranged on the anode current collector, the anode wound electrode body 20 is sandwiched therebetween in a active material layer includes an anode active material includ direction perpendicular to a peripheral winding Surface. ing at least one of silicon and tin as an element, and the anode In the opened end portion of the battery can 11, a battery active material includes a coating film including an oxide of at cover 14, and a safety valve mechanism 15 and a positive least one kind selected from the group consisting of silicon, temperature coefficient device (PTC device) 16 arranged germanium and tin and a halide of at least one kind selected inside the battery cover 14 are mounted by caulking by a from the group consisting of silicon, germanium and tin in at gasket 17, and the interior of the battery can 11 is sealed. The least a part of its Surface. battery cover 14 is made of for example, the same material as In the second anode according to the invention, a coating that of the battery can 11. The safety valve mechanism 15 is film including an oxide of at least one kind selected from the 10 electrically connected to the battery cover 14 through the PTC group consisting of silicon, germanium and tin and a halide of device 16, and in the safety valve mechanism 15, when an at least one kind selected from the group consisting of silicon, internal pressure in the battery increases to a certain extent or germanium and tin is arranged on at least a part of a surface of higher due to an internal short circuit or external application the anode active material, so chemical stability can be of heat, a disk plate 15A is flipped so as to disconnect the improved. Therefore, in the second battery using the second 15 electrical connection between the battery cover 14 and the anode, charge-discharge efficiency can be improved. spirally wound electrode body 20. When a temperature rises, the PTC device 16 limits a current by an increased resistance BRIEF DESCRIPTION OF THE DRAWINGS to prevent abnormal heat generation by a large current. The gasket 17 is made of for example, an insulating material, and FIG. 1 is a sectional view showing a configuration of a first its Surface is coated with asphalt. type secondary battery according to a first embodiment of the A center pin 24 is inserted into the center of the spirally invention. wound electrode body 20. In the spirally wound electrode FIG. 2 is an enlarged sectional view showing a part of a body 20, a cathode lead 25 made of aluminum (Al) or the like spirally wound electrode body in the secondary battery shown is connected to the cathode 21, and an anode lead 26 made of in FIG. 1. 25 nickel or the like is connected to the anode 22. The cathode FIG. 3 is an exploded perspective view showing a second lead 25 is welded to the safety valve mechanism 15 so as to be type secondary battery according to the first embodiment of electrically connected to the battery cover 14, and the anode the invention. lead 26 is welded to the battery can 11 so as to be electrically FIG. 4 is a sectional view showing a configuration of a connected to the battery can 11. spirally wound electrode body taken along a line IV-IV of 30 FIG. 2 shows an enlarged view of a part of the spirally FIG. 3. wound electrode body 20 shown in FIG.1. The cathode 21 has FIG.5 is a schematic enlarged sectional view of a part of an a configuration in which a cathode active material layer 21B anode of a secondary battery according to a second embodi is arranged on both sides of a cathode current collector 21A ment of the invention. having a pair of facing Surfaces. The cathode current collector FIG. 6 is a sectional view showing a configuration of a 35 21A is made of, for example, a metal material Such as alumi secondary battery formed in examples. l FIG. 7 is a schematic enlarged sectional view of a part of an The cathode active material layer 21B includes, for anode shown in FIG. 6. example, one kind or two or more kinds of cathode materials FIG. 8 is a schematic enlarged sectional view of a part of an capable of inserting and extracting lithium as cathode active anode active material layer formed in Comparative Example 40 materials, and the cathode active material layer 21 B may 1-2. include an electrical conductor Such as a carbon material and FIG. 9 is an illustration showing an example of peaks a binder such as polyvinylidene , if necessary. For obtained by X-ray photoelectron spectroscopy relating to a example, as the cathode material capable of inserting and SnCoC-containing material formed in an example. extracting lithium, a chalcogenide which does not include 45 lithium such as titanium sulfide (TiS), molybdenum sulfide BEST MODE FOR CARRYING OUT THE (MoS), niobium selenide (NbSea) or vanadium oxide INVENTION (VOs) or a lithium-containing compound including lithium is cited. Preferred embodiments will be described in detail below Among them, the lithium-containing compound is prefer referring to the accompanying drawings. 50 able, because some of the lithium-containing compounds can obtain a high Voltage and a high energy density. AS Such a First Embodiment lithium-containing compound, for example, a complex oxide including lithium and a transition metal element, or a phos (First Type Battery) phate compound including lithium and a transition metal FIG. 1 shows a sectional configuration of a first type sec 55 element is cited, and in particular, a lithium-containing com ondary battery according to a first embodiment of the inven pound including at least one kind selected from the group tion. The secondary battery is a so-called cylindrical type, and consisting of cobalt, nickel, manganese and iron is preferable. includes a spirally wound electrode body 20 which includes a It is because a higher Voltage can be obtained. The chemical strip-shaped cathode 21 and a strip-shaped anode 22 spirally formula of the lithium-containing compound is represented wound with a separator 23 in between in a substantially 60 by, for example, Li MIO, or Li MIIPO. In the formulas, MI hollow cylindrical-shaped battery can 11. The battery can 11 and MII each represent one or more kinds of transition metal is made of for example, nickel-plated iron, and an end portion elements. The values of Xandy depend on a charge-discharge of the battery can 11 is closed, and the other end portion state of the battery, and are generally within a range of thereof is opened. An electrolytic solution as a liquid electro 0.05sXs 1.10 and 0.05sys1.10, respectively. lyte is injected into the battery can 11, and the separator 23 is 65 Specific examples of the complex oxide including lithium impregnated with the electrolytic solution. Moreover, a pair and a transition metal element include lithium-cobalt com of insulating plates 12 and 13 are arranged so that the spirally plex oxide (Li CoO), lithium-nickel complex oxide (Li US 8,932,761 B2 5 6 NiO), lithium-nickel-cobalt complex oxide (LiNiCo-O. The SnCoC-containing material includes a phase includ (Z-1)), lithium-nickel-cobalt-manganese complex oxide ing tin, cobalt and carbon, and the phase preferably has a low (LiNiCo, MnO, (v--w:1)), lithium-manganese com crystalline structure oran amorphous structure. Moreover, in plex oxide (LiMnO) having a spinel structure. Among the SnCoC-containing material, at least a part of carbon as an them, a complex oxide including nickel is preferable. It is element is preferably bonded to a metal element or a metal because a high capacity can be obtained, and Superior cycle loid element as another element. It is considered that a decline characteristics can be obtained. Specific examples of the in the cycle characteristics is caused by cohesion or crystal phosphate compound including lithium and a transition metal lization of tin or the like, and when carbon is bonded to element include a lithium-iron phosphate compound another element, such cohesion or crystallization can be pre 10 vented. (LiFePO) and a lithium-iron-manganese phosphate com As a measuring method for checking the bonding state of pound (LiFe,MnPO (u-1)). an element, for example, X-ray photoelectron spectroscopy For example, as in the case of the cathode 21, the anode 22 (XPS) is used. In the XPS, the peak of the 1s orbit (C1s) of has a configuration in which an anode active material layer carbon in the case of graphite is observed at 284.5 eV in an 22B is arranged on both sides of an anode current collector 15 apparatus in which energy calibration is performed so that the 22A having a pair of facing Surfaces. The anode current peak of the 4f orbit (Au4f) of a gold atom is observed at 84.0 collector 22A is made of for example, a metal material Such eV. Moreover, the peak of C1s of the surface contamination as copper. carbon is observed at 284.8 eV. On the other hand, in the case The anode active material layer 22B includes an anode where the charge density of the carbon element increases, for active material including at least one of silicon and tin as an example, in the case where carbon is bonded to a metal element. It is because silicon and tin have a high capability to element or a element, the peak of C1s is observed in insert and extract lithium, and can obtain a high energy den a region lower than 284.5 eV. In other words, in the case S1ty. where the peak of the composite wave of C1s obtained in the Examples of the anode active material including at least SnCoC-containing material is observed in a region lower than one of silicon and tin include the simple Substance, an alloy 25 284.5 eV, at least a part of carbon included in the SnCoC and a compound of silicon, and the simple Substance, an alloy containing material is bonded to the metal element or the and a compound of tin, and an anode active material including metalloid element which is another element. a phase including one kind or two or more kinds selected from Moreover, in the XPS measurement, for example, the peak them at least in part. In the invention, the alloy includes an of C1s is used to correct the energy axis of a spectrum. In alloy including one or more kinds of metal elements and one 30 general, Surface contamination carbon exists on a material or more kinds of metalloid elements in addition to an alloy Surface, so the peak of C1s of the Surface contamination including two or more kinds of metal elements. Further, the carbon is fixed at 284.8 eV. and the peak is used as an energy alloy may include a non-metal element. As the texture of the reference. In the XPS measurement, the waveform of the peak alloy, a solid solution, a eutectic (eutectic mixture), an inter of C1s is obtained as a form including the peak of the surface metallic compound or the coexistence of two or more kinds 35 contamination carbon and the peak of carbon in the SnCoC selected from them is cited. containing material, so the peak of the Surface contamination As an alloy of silicon, for example, an alloy including at carbon and the peak of the carbon in the SnCoC-containing least one kind selected from the group consisting of tin, nickel material are separated by analyzing the waveform through the (Ni), copper (Cu), iron (Fe), cobalt (Co), manganese (Mn), use of for example, commercially available software. In the Zinc (Zn), indium (In), silver (Ag), titanium (Ti), germanium, 40 analysis of the waveform, the position of a main peak existing bismuth (Bi), antimony (Sb) and chromium (Cr) as a second on a lowest binding energy side is used as an energy reference element in addition to silicon is cited. As an alloy of tin, for (284.8 eV). example, an alloy including at least one kind selected from the Such an anode active material can be manufactured, for group consisting of silicon, nickel, copper, iron, cobalt, man example, by mixing the materials of all elements to form a ganese, Zinc, indium, silver, titanium, germanium, bismuth, 45 mixture, melting the mixture in an electric furnace, a high antimony and chromium as a second element in addition to tin frequency induction furnace, an arc furnace or the like, and is cited. then Solidifying the mixture, or by various atomization meth As a compound of silicon and a compound of tin, for ods such as gas atomization or water atomization, various roll example, a compound including oxygen (O) or carbon (C) is methods, or methods using a mechanochemical reaction Such cited, and the compound may include the above-described 50 as a mechanical alloying method or a mechanical milling second element in addition to silicon or tin. method. Among them, the anode active material is preferably Among them, a SnCoC-containing material in which tin, manufactured by a method using a mechanochemical reac carbon and cobalt are included as elements, and the carbon tion. It is because the anode active material can have a low content is within a range from 9.9 wt % to 29.7 wt % both crystalline structure or an amorphous structure. In this inclusive, and the ratio of cobalt to the total of tin and cobalt 55 method, for example, a manufacturing apparatus such as a (Co/(Sn+Co)) is within a range from 30 wt % to 70 wt.% both planetary ball mill or an attritor can be used. inclusive is preferably included. It is because a high energy The anode active material layer 22B may further include density and Superior cycle characteristics can be obtained in any other anode active material or any other material Such as Such a composition range. an electrical conductor in addition to the above-described The SnCoC-containing material may further include any 60 anode active material. As the other anode active material, for other element, if necessary. As the element, for example, example, a carbonaceous material capable of inserting and silicon, iron, nickel, chromium, indium, niobium (Nb), ger extracting lithium is cited. The carbonaceous material is pref manium, titanium, molybdenum (Mo), aluminum, phospho erable, because charge-discharge cycle characteristics can be rus (P), gallium (Ga) or bismuth is preferable, and two or improved, and the carbonaceous material also functions as an more kinds selected from them may be included. It is because 65 electrical conductor. As the carbonaceous material, for the capacity or the cycle characteristics can be further example, one kind or two or more kinds selected from the improved. group consisting of non-graphitizable carbon, graphitizable US 8,932,761 B2 7 8 carbon, graphite, kinds of pyrolytic carbon, kinds of coke, particles covered with the above-described oxide-containing kinds of glass-like carbon, a fired organic polymer body, film. The metal includes a metal element not alloyed with an activated carbon, and carbon black can be used. Among them, electrode reactant. As the metal element, at least one kind kinds of coke include pitchcoke, needle coke, petroleum coke selected from the group consisting of iron (Fe), cobalt (Co), and the like, and the fired organic polymer body is formed by nickel (Ni), Zinc (Zn) and copper (Cu) is cited. In Such a firing a polymer compound Such as a phenolic resin or a furan configuration, the anode active material particles are bonded resin at an appropriate temperature to carbonize the polymer by the metal. compound. The carbonaceous materials may have a fiber To improve the bonding property of the metal, it is desired form, a spherical form, a particle form or a scale form. to sufficiently fill gaps between adjacent anode active mate The anode active material layer 22B includes anode active 10 rial particles with the metal. In this case, a part of gaps may be material particles made of the above-described anode active filled with the metal; however, a larger filling amount of the material. On a region in contact with the electrolytic Solution metal is more preferable. It is because the bonding property of of the Surface of each anode active material particle, that is, a the anode active material layer 22B is improved. region except for a region in contact with the anode current Moreover, Such a metal may be fixed not only in the gaps collector 22A, the binder or other anode active material par 15 between anode active material particles but also on the sur ticles, an oxide-containing film including an oxide of at least faces of the anode active material particles. It is because the one kind selected from silicon, germanium and tin is formed. Surface area of the anode active material particles can be It is desirable that the oxide-containing film is formed on reduced, and the formation of an irreversible film which may nearly the whole region in contact with the electrolytic solu be a potential impediment to the progress of electrode reac tion of the Surface of each anode active material particle, and tion can be prevented. For example, in the case where the most of anode active material particles are not exposed. anode active material particles are formed by a vapor-phase The oxide-containing film may be formed by a liquid method or the like, beard-like fine projections are formed on phase method such as a liquid-phase deposition method, a the Surfaces of the anode active material particles, so a large sol-gel method, a coating method or dip coating method. number of gaps between the projections are formed. The gaps Among them, the oxide-containing film is preferably 25 cause an increase in the Surface area of the anode active formed by a liquid-phase deposition method. It is because by material particles; however, when the above-described metal the liquid-phase deposition method, the oxide-containing is arranged in advance, the irreversible film formed on the film can be deposited by easily controlling an oxide. The Surfaces of the anode active material particles is reduced. liquid-phase deposition methodis, for example, a a method of The separator 23 isolates between the cathode 21 and the depositing an oxide on a Surface of the anode active material 30 anode 22 so that lithium pass therethrough while pre layer 22B to form the oxide-containing film by adding a venting a short circuit of a current due to contact between the dissolved species which easily coordinates (F) as an cathode 21 and the anode 22. The separator 23 is made of for anion trapping agent to a solution of a fluoride complex of example, a porous film of a synthetic resin Such as polytet silicon, tin or germanium to mix them, and immersing the rafluoroethylene, polypropylene or polyethylene, or a porous anode current collector 22A on which the anode active mate 35 ceramic film, and the separator 23 may have a configuration in rial layer 22B is formed in the mixture, and then trapping a which two or more kinds of the porous films are laminated. fluorine anion generated from the fluoride complex by the The electrolytic solution with which the separator 23 is dissolved species. Instead of the fluoride complex, for impregnated includes a solvent and an electrolyte Salt dis example, a silicon compound, a tin compound or a germa solved in the solvent. nium compound generating another anion Such as a Sulfate 40 Examples of the solvent include ethylene carbonate, pro ion may be used. Moreover, in the case where the oxide pylene carbonate, butylene carbonate, dimethyl carbonate, containing film is formed by the sol-gel method, a treatment diethyl carbonate, ethyl methyl carbonate, methyl propylcar liquid including a fluorine anion, or a compound including bonate, Y-butyrolactone, Y-Valerolactone, 1,2-dimethoxy fluorine and one kind selected from the group consisting of ethane, tetrahydrofuran, 2-methyltetrahydrofuran, tetrahy Group 13 to 15 elements (more specifically, a fluorine ion, a 45 dropyran, 1.3-dioxolane, 4-methyl-1,3-dioxolane, 1.3- tetrafluoroborate ion, a ion or the like) dioxane, 1,4-dioxane, methyl acetate, ethyl acetate, methyl as a reaction accelerator may be used. It is because in the propionate, ethyl propionate, methylbutyrate, methyl isobu oxide-containing film obtained by Such a manner, the content tyrate, methyl trimethylacetate, ethyl trimethylacetate, aceto of an alkoxy group is low, and a gas generation amount in the nitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, case where the oxide-containing film functions as an anode in 50 3-methoxypropionitrile, N,N-dimethylformamide, N-meth an electrochemical device Such as a battery is reduced. ylpyrrolidinone, N-methyloxazolidinone, N,N-dimethylimi For example, the thickness of the oxide-containing film is dazolidinone, nitromethane, nitroethane, Sulfolane, trimethyl preferably within a range from 0.1 nm to 500 nm both inclu phosphate, dimethylsulfoxide, dimethylsulfoxide phosphate sive. It is because when the thickness is 0.1 nm or more, the and the like. Only one kind or mixture of a plurality of kinds anode active material particles can be covered with the oxide 55 selected from them may be used. Among them, at least one containing film, and when the thickness is 500 nm or less, a kind selected from the group consisting of ethylene carbon decline in energy density can be prevented. Moreover, for ate, propylene carbonate, dimethyl carbonate, diethylcarbon example, the thickness is more preferably within a range from ate and ethyl methyl carbonate is preferable. It is because 1 nm to 200 nm both inclusive, and more preferably from 10 better cycle characteristics can be obtained. In this case, in nm to nm both inclusive, and more preferably from 20 nm to 60 particular, Among them, the solvent preferably includes a 100 nm both inclusive. It is because anode active material mixture of a high-viscosity (high-permittivity) solvent (for particles 22C can be sufficiently covered, and a decline in example, relative permittivity ea30) such as ethylene carbon energy density can be reduced, and a higher effect can be ate or propylene carbonate and a low-viscosity solvent (for obtained. example, Viscositys 1 mPas) such as dimethyl carbonate, The anode active material layer 22B preferably includes a 65 ethyl methyl carbonate or diethyl carbonate. It is because the metal formed in gaps between adjacent anode active material dissociation property of the electrolyte salt and ion mobility particles together with a plurality of anode active material are improved, so a higher effect can be obtained. US 8,932,761 B2 10 The solvent preferably further includes a cyclic carbonate (where R21 to R24 each represent a group, a including an unsaturated bond. It is because the decomposi halogen group, an alkyl group or a halogenated alkyl group, tion reaction of the electrolytic solution including Such a and they may be the same as or different from one another, Solvent is further prevented, and cycle characteristics are and at least one of them is a halogen group or a halogenated further improved. As the cyclic carbonate including an unsat alkyl group.) urated bond, for example, at least one kind selected from the As the chain carbonate represented by 1 group consisting of a vinylene carbonate-based compound, a which includes a halogen as an element, for example, fluo vinylethylene carbonate-based compound and an ethylene romethyl methyl carbonate, bis(fluoromethyl)carbonate, dif methylene carbonate-based compound is cited. luoromethyl methylcarbonate and the like are cited. Only one Examples of the vinylene carbonate-based compound 10 kind or mixture of a plurality ofkinds selected from them may include vinylene carbonate (1,3-dioxol-2-one), methylvii be used. nylene carbonate (4-methyl-1,3-dioxol-2-one), ethylvii nylene carbonate (4-ethyl-1,3-dioxol-2-one), 4,5-dimethyl As the cyclic carbonate represented by Chemical Formula 1,3-dioxol-2-one, 4,5-diethyl-1,3-dioxol-2-one, 4-fluoro-1, 2 which includes a halogen as an element, a series of com 3-dioxol-2-one, 4-trifluoromethyl-1,3-dioxol-2-one and the 15 pounds represented by Chemical Formulas 3 and 4 are cited. like. More specifically, 4-fluoro-1,3-dioxolane-2-one in Chemical Examples of the vinylethylene carbonate-based compound Formula 3(1), 4-chloro-1,3-dioxolane-2-one in Chemical include vinylethylene carbonate (4-vinyl-1,3-dioxolane-2- Formula 3(2), 4,5-difluoro-1,3-dioxolane-2-one in Chemical one), 4-methyl-4-vinyl-1,3-dioxolane-2-one, 4-ethyl-4-vi nyl-1,3-dioxolane-2-one, 4-n-propyl-4-vinyl-1,3-dioxolane Formula 3(3), tetrafluoro-1,3-dioxolane-2-one in Chemical 2-one, 5-methyl-4-vinyl-1,3-dioxolane-2-one, 4.4-divinyl-1, Formula 3(4), 4-fluoro-6-chloro-1,3-dioxolane-2-one in 3-dioxolane-2-one, 4,5-divinyl-1,3-dioxolane-2-one and the Chemical Formula 3 (5), 4,5-dichloro-1,3-dioxolane-2-one in like. Chemical Formula 3 (6), tetrachloro-1,3-dioxolane-2-one in Examples of the ethylene methylene carbonate-based com Chemical Formula 3 (7), 4,5-bistrifluoromethyl-1,3-diox pound include 4-methylene-1,3-dioxolane-2-one, 4.4-dim 25 olane-2-one in Chemical Formula 3(8), 4-trifluoromethyl-1, ethyl-5-methylene-1,3-dioxolane-2-one, 4,4-diethyle-5-me 3-dioxolane-2-one in Chemical Formula 3 (9), 4.5-difluoro thylene-1,3-dioxolane-2-one and the like. 4,5-dimethyl-1,3-dioxolane-2-one in Chemical Formula Only one kind or mixture of a plurality of kinds selected 3(10), 4-methyl-5,5-difluoro-1,3-dioxolane-2-one in Chemi from them may be used. Among them, as the cyclic carbonate cal Formula 3(11), 4-ethyl-5,5-difluoro-1,3-dioxolane-2-one including an unsaturated bond, at least one kind selected from 30 the group consisting of vinylene carbonate and vinyl ethylene in Chemical Formula 3(12) and the like are cited. Moreover, carbonate is preferable. It is because a sufficient effect can be 4-trifluoromethyl-5-fluoro-1,3-dioxolane-2-one in Chemical obtained. In this case, in particular, vinylene carbonate is Formula 4(1), 4-trifluoromethyl-5-methyl-1,3-dioxolane-2- more preferable than vinyl ethylene carbonate. It is because a one in Chemical Formula 4(2), 4-fluoro-4,5-dimethyl-1,3- higher effect can be obtained. 35 dioxolane-2-one in Chemical Formula 4(3), 4.4-difluoro-5- Moreover, for example, the solvent preferably includes at (1,1-difluoroethyl)-1,3-dioxolane-2-one in Chemical least one kind selected from the group consisting of a chain Formula 4(4), 4,5-dichloro-4,5-dimethyl-1,3-dioxolane-2- carbonate represented by Chemical Formula 1 which one in Chemical Formula 4(5), 4-ethyl-5-fluoro-1,3-diox includes a halogen as an element and a cyclic carbonate olane-2-one in Chemical Formula 4 (6), 4-ethyl-4,5-difluoro represented by Chemical Formula 2 which includes a halogen 40 as an element. It is because the decomposition reaction of the 1,3-dioxolane-2-one in Chemical Formula 4(7), 4-ethyl-4,5, electrolytic solution including the solvent is further pre 5-trifluoro-1,3-dioxolane-2-one in Chemical Formula 4(8), vented, and cycle characteristics are improved. 4-fluoro-4-methyl-1,3-dioxolane-2-one in Chemical For mula 4(9) and the like are cited. Only one kind or mixture of 45 a plurality of kinds selected from them may be used. Among Chemical Formula 1 them, as the cyclic carbonate including a halogen as an ele R14 ment, at least one kind selected from the group consisting of R12-C-O-C-O-C-R15 4-fluoro-1,3-dioxolane-2-one and 4,5-difluoro-1,3-diox R11 O R16 50 olane-2-one is preferable. It is because they are easily avail able, and a sufficient effect can be obtained. In this case, in (where R11 to R16 each represent a hydrogen group, a particular, 4,5-difluoro-1,3-dioxolane-2-one is more prefer halogen group, an alkyl group or a halogenated alkyl group, able than 4-fluoro-1,3-dioxolane-2-one. It is because a higher and they may be the same as or different from one another, effect can be obtained. More specifically, to obtain a higher and at least one of them is a halogen group or a halogenated 55 effect, a trans-isomer is more preferable than a cis-isomer. alkyl group.) Chemical Formula 3 Chemical Formula 2) H H H H H H R22 R23 V M 60 V M V M V M R21-p-- R24 H f- F H-f- c. F p- F ON-O O NYO O NYO O N1O

65 O O O US 8,932,761 B2 11 12 -continued As the Sultone, for example, propane Sultone, propene Sul tone or the like is cited. Only one kind or mixture of a plurality 'V / " ' " ' ofkinds selected from them may be used. Among them, as the F-CQN F C-CON F C-C CNC sultone, propene sultone is preferable. Moreover, the content 4 y, " " ( ), " " ( ), of the sultone in the electrolytic solution is preferably within NY NY NY a range from 0.5 wt % to 3 wt % both inclusive. It is because | || | a sufficient effect can be obtained. (4) (5) (6) As the acid anhydride, for example, Succinic anhydride, C FC CF H CF glutaric anhydride, maleic anhydride, Sulfobenzoic anhy V / V / V W 10 dride, sulfopropionic anhydride, sulfobutyric anhydride or c-f- C H-f-sh H-f-sh the like is cited. Only one kind or mixture of a plurality of O O O O O O kinds selected from them may be used. Among them, as the NY N1 NY acid anhydride, at least one kind selected from the group consisting of succinic anhydride and Sulfobenzoic anhydride I I I 15 is preferable. It is because a sufficient effect can be obtained. (7) (8) (9) In this case, in particular, Sulfobenzoic anhydride is more H H / preferable than Succinic anhydride. It is because a higher HC CH F CH F SS effect can be obtained. The content of the acid anhydride in the electrolytic solution is preferably within a range from 0.5 F- C o c?NF F-Y. o c{NH F-Y. o c?NH CH3 wt % to 3 wt % both inclusive. It is because a sufficient effect can be obtained. ckC J. d C -) d C ch For example, the electrolyte salt preferably includes at least one kind selected from the group consisting of com I l I pounds represented by Chemical Formulas 5, 6 and 7. It is (10) (11) (12) 25 because sufficient electrical conductivity can be stably Chemical Formula 4 obtained, and cycle characteristics can be improved. Only one F CF FC CH3 H3C CH3 kind or mixture of a plurality of kinds selected from the / / M compounds represented by Chemical Formulas 5 to 7 may be H Y-c H ------, used. / \ / \ / \ 30 ONY O ONY O O NYO | | Chemical Formula 5 O O O in3 (1) (2) (3) O F 35 FNn / F C HC CH (nic O D-al-Risa3 Y (NCH; "Y / " F-, H c-f- c. (where X31 represents a Group 1A element or a Group 2A O O O O element in the shortform of the periodic table of the elements, Y NY 40 or aluminum, M31 represents a transition metal, or a Group O l 3B element, a Group 4B element or a Group 5B element in the (4) (5) short form of the periodic table of the elements, R31 repre sents a halogen group, Y31 represents —OC R32-CO , H. " H t —OC CR33- or —OC CO , R32 represents an alky H SC F S. 45 lenegroup, a halogenated alkylene group, an arylenegroup or eY-cé s CH -Y-(- CH a halogenated arylene group, R33 represents an alkyl group, F / V H H { ), F a halogenated alkyl group, an aryl group or a halogenated aryl OS- NY group and may be the same as or different from each other, a3 | 50 is an integer of 1 to 4. b3 is an integer of 0, 2 or 4, and c3, d3. O O m3 and n3 each are an integer of 1 to 3.) (6) (7)

H n Ji Chemical Formula 6 F C H CH in4 Y-cé YCH, V 3 55 O O N On F- F H-f-st M41 Y41 X4114t O O M o1 fa: NY OS O O a4 | e4 O O 60 (8) (where X41 represents a Group 1A element or a Group 2A element in the shortform of the periodic table of the elements, Moreover, for example, the solvent preferably further M41 represents a transition metal, or a Group 3B element, a includes a Sultone (a cyclic Sulfonate) or an acid anhydride. It Group 4B element or a Group 5B element in the short form of is because the decomposition reaction of the electrolytic solu 65 the periodic table of the elements, Y41 represents —OC tion including the solvent is further prevented, and cycle (CR41)-CO——R43C-(CR42)4-CO— —R432C characteristics are improved. (CR42)-CR43-, -R43C-(CR42) -SO —OS— US 8,932,761 B2 13 14 (CR42)a-SO - or —OC-(CR42) -SO. , R41 and -continued R43 each representahydrogen group, an alkyl group, a halo gen group or a halogenated alkyl group and may be the same as or different from each other, and at least one of R41 and at least one of R43 each are a halogen group or a halogenated alkyl group, R42 represents a hydrogen group, an alkyl group, a halogen group or a halogenated alkyl group and may be the same as or different from each other, a4, e4 and na each are an CF O integer of 1 or 2, b4 and d4 each are an integer of 1 to 4, ca is 10 CF Y1 F Li" an integer of 0 to 4, and f4 and m4 each are an integer of 1 to 3 c? NF 3.) O (3) Chemical Formula 7 15 CF O O CF Rf.5 O M / -- SM51 DYS 1 X51." CF B CF Li F15 O 5 O o/ Y O (4) (where X51 represents a Group 1A element or a Group 2A O F element in the shortform of the periodic table of the elements, \l-F Li" M51 represents a transition metal, or a Group 3B element, a M NF Group 4B element or a Group 5B element in the short form of O O the periodic table of the elements, Rf represents a fluorinated alkyl group having 1 to 10 carbon atoms or a fluorinated aryl 25 (5) group having 1 to 10 carbon atoms, Y51 represents —OC O O O O M / -- (CR51)s-CO—, —R52C-(CR51)s-CO—, B Li —R52C (CR51)-CR52-, —R52C-(CR51)s- M. N. SO. , —OS—(CR51)s-SO - or —OC-(CR51)s- O O O O SO. , R51 represents a hydrogen group, an alkyl group, a 30 halogen group or a halogenated alkyl group and may be the (6) same as or different from each other, R52 represents a hydro Chemical Formula 9 gen group, an alkyl group, a halogen group or a halogenated O alkyl group and may be the same as or different from each O O other, and at least one of R52 is a halogen group or a haloge 35 V/ F nated alkyl group, a5. fš and n5 each are an integer of 1 or 2, /v Li b5, c5 and e5 each are an integer of 1 to 4, d5 is an integer of O O O F 0 to 4, and g5 and mS each are an integer of 1 to 3.) As examples of the compounds represented by Chemical O Formulas 5 to 7, compounds represented by Chemical For 40 (1) mulas 8 and 9 are cited. As the compound represented by Chemical Formula 5, for O O O CF N / -- example, compounds represented by Chemical Formulas 8(1) B CF Li to 8(6) are cited. O c/ Y O As the compound represented by Chemical Formula 6, for 45 example, compounds represented by Chemical Formulas 9(1) (2) to 9(8) are cited. As the compound represented by Chemical Formula 7, for O O O CF M / -- example, a compound represented by Chemical Formula 9(9) B H Li is cited. M M Only one kind or a mixture of a plurality of kinds selected 50 O O O O from them may be used. Among them, as the compounds (3) represented by Chemical Formulas 5 to 7, the compounds O O O CF represented by Chemical Formulas 8(6) and 9(2) are prefer M / -- able. It is because a sufficient effect can be obtained. As long B CH3 Li as the compounds have a configuration represented by 55 c/ Y Chemical Formulas 5 to 7, they are not limited to the com O O pounds represented by Chemical Formula 8 or 9. (4) CF 60 CF Chemical Formula 8 O V/O H /v Li O O O H

65 (5) US 8,932,761 B2 15 16 -continued by Chemical Formulas 10 to 12 together with lithium CF3 hexafluorophosphate or the like, a higher effect can be O O O CF obtained. N / B Li" LiN(CF2SO2)(CF2SO2) Chemical Formula 10 M N O O O CF (where mand neach are an integer of 1 or more and may be CF the same as or different from each other.) (6) Chemical Formula 11 CF3 10 O CH3 O\/ O B Li /N ODO o/ /Y. H -- N/ O 15 / \, (7) CF (R61 represents a straight-chain or branch perfluoroalky O H lene group having 2 to 4 carbon atoms.) LiC(CF2SO2)(CF2SO2)(C.F2SO2) (Chemical Formula 12 (where p, q and reach are an integer of 1 or more and may O ? Y. H be the same as or different from one another.) As the chain compound represented by Chemical Formula O 10, lithium bis(trifluoromethanesulfonyl)imide (LiN ( 8) 25 (CFSO)), lithium bis(pentafluoroethanesulfonyl)imide (LiN(CFSO)), lithium (trifluoromethanesulfonyl)(pen tafluoroethanesulfonyl)imide (LiN(CFSO) (CFSO)), lithium (trifluoromethanesulfonyl)(heptafluoropropane sulfonyl)imide (LiN(CFSO) (CFSO)) or lithium (trifluo 30 romethanesulfonyl)(nonafluorobutanesulfonyl)imide (LiN (CFSO) (CFSO)) and the like are cited. Only one kind or mixture of a plurality of kinds selected from them may be used. Moreover, for example, the electrolyte salt preferably As the cyclic compound represented by Chemical Formula includes any other electrolyte salt together with the com 11, a series of compounds represented by Chemical Formula pounds represented by Chemical Formulas 5 to 7. It is 35 13 are cited. More specifically, lithium 1.2-perfluoroet because a higher effect can be obtained. Examples of the other hanedisulfonylimide in Chemical Formula 13(1), lithium 1,3- electrolyte salt include lithium hexafluorophosphate (LiPF), perfluoropropanedisulfonylimide in Chemical Formula lithium tetrafluoroborate (LiBF), lithium perchlorate 13(2), lithium 1,3-perfluorobutanedisulfonylimide in Chemi (LiCIO), lithium hexafluoroarsenate (LiAsF), lithium tet cal Formula 13(3), lithium 1,4-perfluorobutanedisulfonylim raphenyl borate (LiB(CHs)), lithium methanesulfonate 40 ide in Chemical Formula 13(4) and the like are cited. Only (LiCHSO), lithium trifluoromethanesulfonate (LiCFSO), one kind or mixture of a plurality of kinds selected from them lithium tetrachloroaluminate (LiAlCl), lithium hexafluoro may be used. Among them, as the cyclic compound repre silicate (LiSiF), lithium chloride (LiCl), lithium bromide sented by Chemical Formula 1 1, lithium 1,3-perfluoropro (LiBr) and the like. Only one kind or a plurality of kinds 45 panedisulfonylimide is preferable. It is because a higher selected from them may be used. Among them, as the other effect can be obtained. electrolyte salt, at least one kind selected from the group consisting of lithium hexafluorophosphate, lithium tetrafluo roborate, lithium perchlorate and lithium hexafluoroarsenate Chemical Formula 13 is preferable. It is because a sufficient effect can be obtained. 50 O O In this case, lithium hexafluorophosphate is more preferable. V MO CF \/ It is because internal resistance declines, so a higher effect can CF-v y:- be obtained. In particular, the electrolyte salt may include the N Lit CF N Li" above-described compounds represented by Chemical For CF-Ns/ er2 -y mulas 5 to 7 together with lithium hexafluorophosphate or the 55 like. / \, / \, Moreover, for example, the electrolyte salt preferably (1) (2) includes compounds represented by Chemical Formulas 10, CF O O O O 11 and 12. It is because a higher effect can be obtained. Only Af \/ F.Y/ one kind or a mixture of a plurality of kinds selected from 60 ;: A CF1 V them may be used. In particular, when the electrolyte salt CF N Lit N Lit includes at least one kind selected from the group consisting r2- s/ CF2CF, ? of the compounds represented by Chemical Formulas 10 to 12 / \, / \, together with lithium hexafluorophosphate or the like, or 65 (4) when the electrolyte salt includes the compounds represented by Chemical Formulas 5 to 7 and the compound represented US 8,932,761 B2 17 18 As the chain compound represented by Chemical Formula accelerator. It is because when Such a reaction accelerator is 12, lithium tris(trifluoromethanesulfonyl)methide (LiC used, hydrolysis reaction is accelerated, and the remaining (CFSO)) or the like is cited. amount of an alkoxy group in the formed oxide-containing The content of the electrolyte salt is preferably within a film is reduced, and as a result, a gas generation amount in the range from 0.3 mol/kg to 3.0 mol/kg both inclusive relative to battery is reduced, thereby swelling of the battery is pre the solvent. When the content of the electrolyte salt is within vented. As the reaction accelerator, more specifically, lithium the range, higher ionic conductivity can be obtained, and hexafluorophosphate, lithium tetrafluorophosphate, hydrof capacity characteristics of the battery can be sufficiently luoric acid, lithium fluoride, sodium hexafluorophosphate, improved. Sodium tetrafluorophosphate, , ammonium When the electrolytic solution with such a composition is 10 hexafluorophosphate, ammonium tetrafluorophosphate, used, the chemical stability of the electrolytic solution is ammonium fluoride or the like is cited. Moreover, as materi improved, and the decomposition reaction in the battery is als of the oxide-containing film by the sol-gel method, tetra prevented. ethoxysilane, tetramethoxysilane, tetrapropoxysilane, tetrai The secondary battery can be manufactured by the follow Sopropoxysilane, tetrabutoxysilane, tetra-2- ing steps, for example. 15 methoxyethoxysilane, di-secondary (Sec)- At first, the cathode 21 is formed. More specifically, at first, butoxyaluminoxytriethoxysilane and an oligomer thereofare the cathode active material, the electrical conductor and the cited. Moreover, a mixture of them may be used. Alterna binder are mixed to form a cathode mixture, and the cathode tively, after these materials are hydrolyzed in a solution mixture is dispersed in a solvent such as N-methyl-2-pyrroli formed by adding water, and an acid (hydrochloric acid, done to form paste-form cathode mixture slurry. Next, after , nitric acid, acetic acid or the like) or an alkali the cathode mixture slurry is applied to the cathode current (ammonia, lithium hydroxide or the like) as a catalyst, and the collector 21A, and the solvent is dried, the cathode mixture reaction accelerator in a solvent such as alcohol, the anode is slurry is compression molded by a roller press or the like to immersed in and taken out of the Solution, then the anode is form the cathode active material layer 21B, thereby the cath dried. A series of processes including immersing, taking out ode 21 is obtained. 25 and drying may be performed several times. Finally, the Next, the anode 22 is formed. More specifically, at first, anode is fired at 150° C. to 1000° C., thereby the oxide after the anode active material including at least one of silicon containing film is obtained. and tin as an element, an electrical conductor and a binder are After the oxide-containing film is formed so that the sur mixed to form an anode mixture, the anode mixture is dis faces of the anode active material particles are selectively persed in a solvent such as N-methyl-2-pyrrolidone to form 30 covered with the oxide-containing film, gaps between adja paste-form anode mixture slurry. Next, the cathode mixture cent anode active material particles are filled with the metal slurry is applied to the anode current collector 22A, and the including a metal element not alloyed with an electrode reac Solvent is dried, and then the anode mixture slurry is com tant by a liquid-phase method or the like. As the metal ele pression molded to form the anode active material layer 22B ment, at least one kind selected from the group consisting of including the anode active material particles made of the 35 iron, cobalt, nickel, Zinc and copper is used. Thereby, the above-described anode active material. anode 22 is obtained. Next, an oxide-containing film including an oxide of at After the cathode 21 and the anode 22 are formed, the least one kind selected from the group consisting of silicon, cathode lead 25 is attached to the cathode current collector germanium and tin is formed on a region in contact with the 21A by welding or the like, and the anode lead 26 is attached electrolytic solution of the surface of each anode active mate 40 to the anode current collector 22A by welding or the like. rial particle, that is, a region except for a region in contact with Next, the cathode 21 and the anode 22 are spirally wound with the anode current collector 22A, the binder or other anode the separator 23 in between, and an end of the cathode lead 25 active material particles by a liquid-phase method. Thus, the is welded to the safety valve mechanism 15, and an end of the oxide-containing film is formed by the liquid-phase method anode lead 26 is welded to the battery can 11, and the cathode which has a Superior Substrate following capability, so the 45 21 and the anode 22 which are spirally wound are sandwiched oxide-containing film is formed in the interior, which cannot between the pair of insulating plates 12 and 13, and they are be not covered with the oxide-containing film by a vapor contained in the battery can 11. After the cathode 21 and the phase method, of the anode active material layer 22B. More anode 22 are contained in the battery can 11, the electrolytic over, the oxide-containing film formed by the liquid-phase Solution is injected into the battery can 11 So as to impregnate method is a film having better properties than those of an 50 the separator 23 with the electrolytic solution. After that, the oxide-containing film formed by air oxidation or the like. The battery cover 14, the safety valve mechanism 15 and the PTC reason of a difference in properties is unknown; however, it is device 16 are fixed in an opened end portion of the battery can considered that it is because of a difference in a film configu 11 by caulking by the gasket 17. Thereby, the secondary ration Such as the size of an oxide particle. battery shown in FIGS. 1 and 2 is completed. More specifically, as the liquid-phase method, the oxide 55 When the secondary battery is charged, lithium ions are containing film is preferably formed by a liquid-phase depo extracted from the cathode 21, and are inserted into the anode sition method, a coating method or a dip coating method. 22 through the electrolytic solution. When the secondary Among them, the liquid-phase deposition method is prefer battery is discharged, the lithium ions are extracted from the able. It is because in the liquid-phase deposition method, an anode 22 and are inserted into the cathode 21 through the oxide can be easily controlled to deposit the oxide-containing 60 electrolytic solution. At this time, the electrolytic solution film. seeps into the interior of the anode active material layer 22B: Moreover, the oxide-containing film may be formed by a however, the oxide-containing film is formed on a region in sol-gel method. In this case, a fluorine anion or a compound contact with the electrolytic solution of the surface of each including fluorine and one kind selected from the group con anode active material particle by the liquid-phase method, so sisting of Group 13 to 15 elements (more specifically, a fluo 65 the region in contact with the electrolytic solution of the rine ion, a tetrafluoroborate ion, a hexafluorophosphate ion or Surface of each anode active material particle are uniformly the like) is preferably added to a treatment liquid as a reaction covered with the oxide-containing film, so chemical stability US 8,932,761 B2 19 20 is increased. Therefore, the decomposition reaction of the ode current collector 33A and the cathode active material electrolytic solution can be prevented, and charge-discharge layer 33B are the same as those of the cathode current col efficiency can be improved. lector 21A and the cathode active material layer 21B in the Thus, in the embodiment, the oxide-containing film is first type battery. formed by the liquid-phase method, so the region in contact The anode 34 has a configuration in which an anode active with the electrolytic solution of the surface of each anode material layer 34B is arranged on both sides of an anode active material particle can be covered with the oxide-con current collector 34A. The anode current collector 34A has taining film, and the chemical stability of the anode 22 can be the same configuration as the anode current collector 22A in improved, and the charge-discharge efficiency can be the first type battery. The anode active material layer 34B improved. 10 Moreover, in the embodiment, the oxide-containing film is includes anode active material particles made of the above formed by the liquid-phase method having Superior Substrate described anode active material as in the case of the anode following capability, so the oxide-containing film can be active material layer 22B in the first type battery, and an formed in the interior, which cannot be covered with the oxide-containing film is formed on a region in contact with an oxide-containing film by a vapor-phase method, of the anode 15 electrolyte of the surface of each anode active material par active material layer 22B, and the anode 22 according to the ticle by a liquid-phase method. Thereby, in the secondary embodiment can be easily formed. battery, as in the case of the first type battery, the chemical In the embodiment, in the case where in the anode active stability of the anode 34 can be improved, and the charge material layer 22B, gaps between a plurality of adjacent discharge efficiency can be improved. The oxide-containing anode active material particles are filled with the metal film includes an oxide of at least one kind selected from group including a predetermined metal element not alloyed with an consisting of silicon, germanium and tin as in the case of the electrode reactant, the anode active material particles are oxide-containing film in the first type battery. The cathode 33 firmly bonded by the metal, so the anode active material layer and the anode 34 are arranged so that the anode active mate 22B resists being pulverized or falling from the anode current rial layer 34B and the cathode active material layer 33B face collector 22A. As a result, cycle characteristics can be 25 each other. improved. The separator 35 has the same configuration as the separa (Second Type Battery) tor 23 in the first type battery. FIG.3 shows the configuration of a second type secondary The electrolyte layer 36 includes an electrolytic solution battery according to the embodiment. The secondary battery and a polymer compound as a holding body which holds the is a so-called laminate film type, and in the secondary battery, 30 electrolytic solution, and is a so-called gel electrolyte. The gel a spirally wound electrode body 30 to which a cathode lead 31 electrolyte is preferable, because the gel electrolyte can and an anode lead 32 are attached is contained in film-shaped obtain high ionic conductivity, and can prevent liquid leakage package members 40. from the battery. The composition of the electrolytic solution The cathode lead 31 and the anode lead 32 are drawn from is the same as that in the first embodiment. As the polymer the interiors of the package members 40 to outside, for 35 compound, for example, an ether-based polymer compound example, in the same direction. The cathode lead 31 and the Such as polyethylene oxide or a cross-link including polyeth anode lead 32 are made of for example, a metal material Such ylene oxide, an ester-based polymer compound Such as poly as aluminum, copper, nickel or stainless in a sheet shape or a methacrylate or an acrylate-based polymer compound, or a mesh shape. polymer of vinylidene fluoride such as polyvinylidene fluo The package members 40 are made of for example, a 40 ride or a copolymer of vinylidene fluoride and hexafluoro rectangular aluminum laminate film including a nylon film, propylene is cited, and one kind or a mixture of two or more aluminum foil and a polyethylene film which are bonded in kinds selected from them is used. More specifically, in terms this order. The package members 40 are disposed so that the of stability of oxidation-reduction, the fluororine-based poly polyethylene film of each of the package members faces the mer compound is preferably used. spirally wound electrode body 30, and edge portions of the 45 The secondary battery can be manufactured by the follow package members 40 are adhered to each other by fusion ing steps, for example. bonding or an adhesive. An adhesive film 41 is inserted At first, the cathode 33 and the anode 34 are formed by the between the package members 40 and the cathode lead 31 and same method as the above-described method of manufactur the anode lead 32 for preventing the entry of outside air. The ing the first type battery, and the electrolyte layer36 is formed adhesive film 41 is made of, for example, a material having 50 by applying a precursor Solution including the electrolytic adhesion to the cathode lead 31 and the anode lead 32, for Solution, the polymer compound and a mixture solvent to the example, a polyolefin resin Such as polyethylene, polypropy cathode 33 and the anode 34, and volatilizing the mixture lene, modified polyethylene or modified polypropylene. solvent. Next, the cathode lead 31 is attached to the cathode In addition, the package members 40 may be made of a current collector 33A, and the anode lead 32 is attached to the laminate film with any other configuration, a polymer film 55 anode current collector 34A. Next, after the cathode 33 on Such as polypropylene or a metal film instead of the above which the electrolyte layer 36 is formed and the anode 34 on described aluminum laminate film. which the electrolyte layer 36 is formed are laminated with FIG. 4 shows a sectional view of the spirally wound elec the separator 35 in between to form a laminate, the laminate trode body 30 taken along a line IV-IV of FIG.3. The spirally is spirally wound in a longitudinal direction, and the protec wound electrode body 30 is a spirally woundlaminate includ 60 tive tape 37 is bonded to an outermost portion of the laminate ing a cathode 33 and an anode 34 with a separator 35 and an so as to form the spirally wound electrode body 30. After that, electrolyte layer 36 in between, and an outermost portion of for example, the spirally wound electrode body 30 is sand the spirally wound electrode body 30 is protected with a wiched between the package members 40, and edge portions protective tape 37. of the package members 40 are adhered to each other by The cathode 33 has a configuration in which a cathode 65 thermal fusion bonding or the like to seal the spirally wound active material layer 33B is arranged on both sides of a electrode body 30 in the package members 40. At this time, cathode current collector 33A. The configurations of the cath the adhesive film 41 is inserted between the cathode lead 31, US 8,932,761 B2 21 22 the anode lead 32 and the package members 40. Thereby, the rial layers 22B and 34B and the anode current collectors 22A secondary battery shown in FIGS. 3 and 4 is completed. and 34A are preferably alloyed at least in apart of an interface Moreover, the battery may be manufactured by the follow therebetween. More specifically, it is preferable that the ele ing steps. At first, after the cathode 33 and the anode 34 are ments of the anode current collectors 22A and 34A are dif formed by the same method as the above-described method of fused into the anode active material layers 22B and 34B in the manufacturing the first type battery, and the cathode lead 31 interface, respectively, or the elements of the anode active and the anode lead 32 are attached to the cathode 33 and the material layers 22B and 34B are diffused into the anode anode 34, respectively, the cathode 33 and the anode 34 are current collectors 22A and 34A in the interface, respectively, laminated with the separator 35 in between to form a lami or they are diffused into each other in the interface. It is nate, and the laminate is spirally wound, and the protective 10 because a fracture in the anode active material layers 22B and tape 37 is bonded to an outermost portion of the spirally 34B due to Swelling and shrinkage thereof according to wound laminate so as to form a spirally wound body as a charge and discharge can be prevented, and electron conduc precursor body of the spirally wound electrode body 30. Next, tivity between the anode active material layers 22B and 34B the spirally wound body is sandwiched between the package and the anode current collectors 22A and 34A can be members 40, and the edge portions of the package members 15 improved. 40 except for one side are adhered by thermal fusion bonding As the vapor-phase method, for example, a physical depo to form a pouched package, thereby the spirally wound body sition method or a chemical deposition method can be used, is contained in the package members 40. An electrolytic and more specifically, a vacuum deposition method, a sput composition which includes the electrolytic Solution and tering method, anion plating method, a laserablation method, monomers as materials of a polymer compound, and if nec a thermal CVD (Chemical Vapor Deposition) method, a essary, any other material Such as a polymerization initiator plasma chemical vapor deposition method, a spraying and a polymerization inhibitor is prepared, and the composi method or the like can be used. As the liquid-phase method, a tion is injected in the package members 40, and then an known technique Such as an electrolytic plating method oran opened portion of the package members 40 are sealed by electroless plating method can be used. The firing method is, thermal fusion bonding. After that, the monomers are poly 25 for example, a method of mixing a particulate anode active merized by applying heat to form the polymer compound, material with a binder or the like to form a mixture, dispersing thereby the gel electrolyte layer 36 is formed. Thus, the sec the mixture into a solvent, applying the solvent, and then ondary battery shown in FIGS. 3 and 4 is assembled. carrying out a heat treatment at a higher temperature than the The secondary battery functions in the same manner as that of the binder or the like. As the firing method, a of the first type battery, and can obtain the same effects as 30 known technique such as, for example, an atmosphere firing those in the first type battery. method, a reaction firing method or a hot press firing method can be used. Second Embodiment Third Embodiment A secondary battery according to a second embodiment 35 will be described below. The secondary battery according to A secondary battery according to a third embodiment of the second embodiment has the same configuration, functions the invention will be described below. The secondary battery and effects as those in the first embodiment, and can be according to the third embodiment of the invention has the manufactured by the same method, except that the anodes 22 same configuration as that in the first embodiment, except for and 34 are formed by a vapor-phase method, a liquid-phase 40 a part of the configurations of the anodes 22 and 34. There method or a firing method. Therefore, in the embodiment, fore, in the embodiment, FIGS. 1, 2, 3 and 4 are referred, and FIGS. 1, 2, 3 and 4 are referred, and like components are like components are denoted by like numerals as of the first denoted by like numerals as of the first embodiment, and will embodiment, and will not be further described. not be further described. As in the case of the first embodiment, the anodes 22 and 34 As in the case of the first embodiment, the anodes 22 and 34 45 have a configuration in which the anode active material layers have a configuration in which anode active material layers 22B and 34B are arranged on both sides of the anode current 22B and 34B are arranged on both sides of anode current collectors 22A and 34A having a pair of facing Surfaces, collectors 22A and 34A, respectively. As in the case of the respectively. The anode active material layers 22B and 34B first embodiment, the anode active material layers 22B and each include the same anode active material as that in the first 34B each include the anode active material including at least 50 embodiment. one of silicon and tin as an element. As in the case of the first In the embodiment, a coating film including an oxide of at embodiment, the anode active material layers 22B and 34B least one kind selected from Silicon, germanium and tin, and include anode active material particles 33C and 34C made of a halide of at least one kind selected from silicon, germanium the above-described anode active material, respectively, and and tin is arranged in at least a part of a Surface of the anode as shown in FIG. 5, in the anode active material particles 22C 55 active material. Thereby, the chemical stability of the anode and 34C. oxide-containing films 22D and 34D are formed on 22 can be improved, and the decomposition of the electrolytic a region in contact with the electrolytic Solution or the elec Solution can be prevented, and the charge-discharge effi trolyte of the surface of each of the anode active material ciency can be improved. In the case where the anode active particles 22C and 34C by a liquid-phase method. Thereby, in material layers 22B and 34B include a plurality of anode the secondary battery, as in the case of the first embodiment, 60 active material particles made of the above-described anode the chemical stability of the anodes 22 and 34 can be active material, the coating film may be formed so that the improved, and the charge-discharge efficiency can be anode active material particles are covered with the coating improved. film, or the coating film may be formed only on the Surfaces Moreover, the anode active material layers 22B and 34B of the anode active material layer 22B and 34B, or the coating are formed by, for example, a vapor-phase method, a liquid 65 film may be formed on the surfaces of the anode active mate phase method or a firing method, or a combination of two or rial layers 22B and 34B as well as between the anode active more methods selected from them, and the anode active mate material particles. US 8,932,761 B2 23 24 As the halide, a fluoride is preferable. It is because lithium the coating film. In the latter case, the coating film may be fluoride is formed at the time of charge and discharge, and the arranged so that both of the anode active material particles surfaces of the anodes 22 and 34 are covered with lithium and the metal arranged in the gaps are covered with the fluoride, thereby the surfaces of the anodes 22 and 34 can be coating film. In Such a configuration, the bonding property further stabilized. between the anode active materials is improved, and the con Moreover, the coating film can be formed by, for example, tact between the anode active material and the electrolytic a liquid-phase deposition method, an electrodeposition solution is prevented, so the decomposition of the electrolytic method, a coating method, a dip coating method, an evapo solution is prevented. Moreover, to improve the bonding ration method, a sputtering method, a CVD (Chemical Vapor property, it is desired to sufficiently fill the gaps between the Deposition) method, a sol-gel method or the like. 10 adjacent anode active material particles with the metal. In this Among them, the coating film is preferably formed by the case, a part of gaps may be filled with the metal; however, the liquid-phase deposition method. It is because by the method, more filling amount of the metal is more preferable. It is the deposition of the coating film can be easily controlled. The because the bonding property of the anode active material liquid-phase deposition method is, for example, a method of layers 22B and 34B is further improved. depositing an oxide and a halide on the Surfaces of the anode 15 Further, the anode active material layers 22B and 34B each active material layers 22B and 34B to form the coating film by have a larger formation area than the cathode active material adding a dissolved species which easily coordinates fluorine layers 21B and 33B. In other words, the anode active material (F) as an anion trapping agent to a solution of a fluoride layers 22B and 34B each include a facing portion facing the complex of silicon, tin or germanium to mix them, and cathode active material layers 21B and 33B and a surplus immersing the anode current collectors 22A and 34A on portion positioned so as to Surround the facing portion (a which the anode active material layers 22B and 34B are portion extending off and not facing the cathode active mate formed in the mixture, and then trapping a fluorine anion rial layers 21B and 33B). In such a configuration, the areas of generated from the fluoride complex by the dissolved species. the anodes 22 and 34 which are supposed to receive lithium Instead of the fluoride complex, for example, a silicon com ions emitted from the cathode 21 during charge is Sufficiently pound, a tin compound or a germanium compound generating 25 secured, so an increase in the current density in ends of the anotheranion Such as a sulfate ion may be used. Moreover, in anode active material layers 22B and 34B can be prevented, the case where the coating film is formed by the sol-gel and the dendrite deposition of metal lithium can be prevented. method, a treatment liquid including a fluorine anion, or a In this case, the coating film may be arranged also on the compound including fluorine and one kind selected from the Surface of the anode active material in the Surplus portions of group consisting of Group 13 to 15 elements (more specifi 30 the anode active material layers 22B and 34B. It is because cally, a fluorine ion, a tetrafluoroborate ion, a hexafluoro even in the case where the positions where the cathode active phosphate ion or the like) as a reaction accelerator may be material layers 21B and 33B and the anode active material used. It is because in the coating film obtained by Such a layers 22B and 34B face each other are shifted by repeating manner, the content of an alkoxy group is low, and a gas charge and discharge, an effect (which will be described later) generation amount in the case where the coating film func 35 by the above-described coating film can be obtained. tions as an anode in an electrochemical device Such as a The secondary battery can be manufactured as in the case battery is reduced. of the first embodiment, except that the anodes 22 and 34 are In the anode active material layers 22B and 34B, a metal formed by the following steps, for example. (for example, a plating film) including a metal element not The anodes 22 and 34 are formed by the following steps. alloyed with an electrode reactant is preferably arranged so 40 More specifically, at first, after the anode active material that the anode active material layers 22B and 34B are fixed to including at least one of silicon and tin as an element, an at least one of the surface of the anode active material and the electrical conductor and a binder are mixed to form an anode Surface of the coating film. As the metal element in this case, mixture, the anode mixture is dispersed in a solvent such as at least one kind selected from the group consisting of iron N-methyl-2-pyrrolidone to form paste-form anode mixture (Fe), cobalt (Co), nickel (Ni). Zinc (Zn) and copper (Cu) is 45 slurry. Next, the anode active material layers 22B and 34B are cited. formed by applying the anode mixture slurry to the anode Sucha metal can reduce the Surface area of the anode active current collectors 22A and 34B, and drying and compression material, and can prevent the formation of an irreversible molding the anode mixture slurry. Next, a coating film includ coating film which may be a potential impediment to the ing an oxide of at least one kind selected from silicon, ger progress of the electrode reaction. For example, in the case 50 manium and tin and a halide of at least one kind selected from where the anode active material particles are formed by a silicon, germanium and tin is formed on the Surface of the vapor-phase method, beard-like fine projections are formed anode active material constituting the anode active material on the Surfaces, so a large number of gaps between the pro layers 22B and 34B by the above-described method, thereby jections are formed. The gaps cause an increase in the Surface the anodes 22 and 34 are obtained. area of the anode active material; however, when the above 55 In this case, in the case where the coating film is formed by described metal is arranged in advance, in the case where the a sol-gel method, a compound including a tetrafluoroborate metal functions as an anode in an electrochemical device Such ion, a hexafluorophosphate ion or a fluorine ion is preferably as a battery, the irreversible film formed on the surfaces of the added to a treatment liquid as a reaction accelerator. It is anode active material particles is reduced. because when Such a reaction accelerator is used, hydrolysis Moreover, in the case where the anode active material 60 reaction is accelerated, and the remaining amount of an layers 22B and 34B each include a plurality of anode active alkoxy group in the formed coating film is reduced, and as a material particles made of the anode active material, it is result, a gas generation amount in the battery is reduced. As desired to arrange the above-described metal in gaps between the reaction accelerator, more specifically, lithium hexafluo the adjacent anode active material particles. In this case, the rophosphate, lithium tetrafluorophosphate, , metal may be arranged in gaps between the anode active 65 lithium fluoride, sodium hexafluorophosphate, sodium tet material particles covered with the coating film, or in gaps rafluorophosphate, Sodium fluoride, ammonium hexafluoro between the anode active materials particles not covered with phosphate, ammonium tetrafluorophosphate, ammonium US 8,932,761 B2 25 26 fluoride or the like is cited. Moreover, as materials of the another by the metal, so the anode active material layers 22B oxide-containing film by the sol-gel method, tetraethoxysi and 34B resist being pulverized or falling from the anode lane, tetramethoxysilane, tetrapropoxysilane, tetraisopro current collectors 22A and 34A. As a result, cycle character poxysilane, tetrabutoxysilane, tetra-2-methoxyethoxysilane, istics can be improved. di-secondary (Sec)-butoxyaluminoxytriethoxysilane, and an 5 oligomer thereof are cited. Alternatively, a mixture of them Fourth Embodiment may be used. After these materials are hydrolyzed in a solu tion formed by adding water, and an acid (hydrochloric acid, A secondary battery according to a fourth embodiment has Sulfuric acid, nitric acid, acetic acid or the like) or an alkali the same configuration, functions and effects as those in the (ammonia, lithium hydroxide or the like) as a catalyst, and the 10 third embodiment, and can be manufactured by the same reaction accelerator in a solvent Such as alcohol, the anode is method as in the case of the third embodiment, except that the immersed in and taken out of the solution, and then the anode configurations of the anodes 22 and 34 are partially different. is dried. A series of processes including immersing, taking Therefore, in the embodiment, FIGS. 1, 2, 3 and 4 are out and drying may be performed several times. Finally, the referred, and like components are denoted by like numerals as anode is fired at 150° C. to 1000°C. to obtain the coating film. 15 Moreover, after or before the coating film is formed on the of the third embodiment, and will not be further described. anode active material, a metal including a metal element not The anodes 22 and 34 have a configuration in which the alloyed with an electrode reactant may be formed by a liquid anode active material layers 22B and 34B are arranged on phase method or the like so as to firmly bond to the surface of both sides of the anode current collectors 22A and 34B, the anode active material or the Surface of the coating film. As respectively, and the anode active material layers 22B and the gold element, at least one kind selected from the group 34B each include an anode active material including at least consisting of iron, cobalt, nickel, Zinc and copper is used. one of silicon and tin as an element as in the case of the third When the secondary battery is charged, lithium ions are embodiment, and a coating film including an oxide of at least extracted from the cathode 21 or 33, and are inserted into the one kind selected from the group consisting of silicon, ger anode 22 or 34 through the electrolytic solution. At this time, 25 manium and tin and a halide of at least one kind selected from the coating film including an oxide of at least one kind the group consisting of silicon, germanium and tin is arranged selected from the group consisting of silicon, germanium and on at least a part of a surface of the anode active material. tin and a halide of at least one kind selected from the group More specifically, the anode active material includes the consisting of silicon, germanium and tin is formed on at least simple Substance, an alloy and a compound of silicon, and the a part of the surface of the anode active material, so the 30 simple Substance, an alloy and a compound of tin, and the chemical stability of the anodes 22 and 34 is improved, and anode active material may include two or more kinds selected the decomposition reaction of the electrolytic solution is pre from them. vented. The possibility that fluorine in the electrolytic solu Moreover, the anode active material layers 22B and 34B tion forms a coating film of a fluoride on the surface of the are formed by, for example, a vapor-phase method, a liquid anode active material by repeating charge and discharge is 35 phase method or a firing method, or a combination of two or considered; however, in this case, the decomposition reaction more methods selected from them, and the anode active mate of the electrolytic solution occurs at the time of forming the rial layers 22B and 34B and the anode current collectors 22A coating film. In the embodiment, the above-described coating and 34A are preferably alloyed at least in apart of an interface film is formed in advance in a manufacturing step, so the therebetween. More specifically, it is preferable that the ele decomposition reaction of the electrolytic Solution can be 40 ments of the anode current collectors 22A and 34A are dif prevented even in a step of performing an initial charge fused into the anode active material layers 22B and 34B, discharge cycle. respectively, or the elements of the anode active material Thus, in the secondary battery according to the embodi layers 22B and 34B are diffused into the anode current col ment, the coating film including an oxide of at least one kind lectors 22A and 34A, respectively, or they are diffused into selected from the group consisting of silicon, germanium and 45 each other in the interface. It is becausea fracture in the anode tin and a halide of at least one kind selected from the group active material layers 22B and 34B due to swelling and consisting of silicon, germanium and tin is arranged on at shrinkage thereof according to charge and discharge can be least a part of the Surface of the anode active material, so the prevented, and the electron conductivity between the anode chemical stability can be improved, and charge-discharge active material layers 22B and 34B and the anode current efficiency can be improved. 50 collectors 22A and 34A can be improved. Moreover, when the metal including a metal element not As the vapor-phase method, for example, a physical depo alloyed with an electrode reactant is formed by a liquid-phase sition method or a chemical deposition method can be used, method or the like so as to be firmly bonded to the surface of and more specifically, a vacuum deposition method, a sput the anode active material or the Surface of the coating film tering method, anion plating method, a laserablation method, after or before the coating film is formed on the surface of the 55 a thermal CVD (Chemical Vapor Deposition) method, a anode active material, the Surface area of the anode active plasma chemical vapor deposition method, a spraying material can be reduced, and the formation of the irreversible method or the like can be used. As the liquid-phase method, a coating film which may be a potential impediment to the known technique Such as an electrolytic plating method oran progress of the electrode reaction can be prevented. electroless plating method can be used. The firing method is, In particular, in the case where the anode active material 60 for example, a method of mixing a particulate anode active layers 22B and 34B each include a plurality of anode active material with a binder or the like to form a mixture, dispersing material particles, when the metal including an metal element the mixture into a solvent, applying the solvent, and then not alloyed with the electrode reactant is formed in gaps carrying out a heat treatment at a higher temperature than the between adjacent anode active material particles by a liquid melting point of the binder or the like. As the firing method, a phase method or the like after or before the coating film is 65 known technique such as, for example, an atmosphere firing formed on the Surfaces of the anode active material particles, method, a reaction firing method or a hot press firing method the anode active material particles are firmly bonded to one can be used. US 8,932,761 B2 27 28 EXAMPLES tion of the surface of each anode active material particle 52C made of silicon. At that time, the concentrations of hexafluo Specific examples of the invention will be described in rostannic acid and aluminum chloride were 0.17 mol/dm and detail below. 0.07 mol/dm, respectively, and the immersing time was 3 hours. After that, the anode current collector 52A was cleaned Examples 1-1 to 1-7 with water, and dried under reduced pressure to form the anode 52. Coin type secondary batteries shown in FIG. 6 were formed. The secondary batteries had a configuration in which In Example 1-7, the anode current collector 52A on which a cathode 51 and an anode 52 were laminated with a separator the anode active material layer 52B was formed was 53 impregnated with an electrolytic solution in between, and immersed in a solution formed by dissolving aluminum chlo they were sandwiched between a package can 54 and a pack ride as an anion trapping agent in hexafluorogermanic acid as age cup 55, and the package can 54 and the package cup 55 a fluoride complex to deposit the oxide-containing film 52D were caulked by a gasket 56. made of germanium oxide on a region in contact with the At first, after an anode active material layer 52B was electrolytic solution of the surface of each anode active mate formed on an anode current collector 52A made of copperfoil rial particles 52C made of silicon. At that time, the concen with a thickness of 10 um by evaporating silicon by an elec trations of hexafluorogermanic acid and aluminum chloride tron beam evaporation method, the anode current collector were 0.17 mol/dm and 0.05 mol/dm, respectively, and the 52A on which the anode active material layer 52B was formed immersing time was 3 hours. After that, the anode current was stamped into a pellet with a diameter of 16 mm. collector 52A was cleaned with water, and dried under Next, in Examples 1-1 to 1-5, the anode current collector reduced pressure to form the anode 52. 52A on which the anode active material layer 52B was formed was immersed in a solution formed by dissolving boric acidas The thickness of the oxide-containing film 52D in each an anion trapping agent in hexafluorosilicic acid as a fluoride example was examined through the use of the formed anode complex, thereby as shown in FIG. 7, an oxide-containing 52 by an SEM (Scanning Electron Microscope). The results film 52D made of silicon oxide (SiO) was deposited on a are shown in Table 1. Moreover, when the oxide-containing region in contact with the electrolytic solution of the surface films 52D were observed, it was confirmed that the oxide of each anode active material particle 52C made of silicon. At containing films 52D were formed in the interiors, which that time, the concentrations of hexafluorosilicic acid and could not be covered by a vapor-phase method, of the anode boric acid were 2 mol/dm and 0.028 mol/dm, respectively. active material layers 52B. TABLE 1 Battery shape: coin type Anode active material: silicon (electron beam evaporation DISCHARGE CAPACITY OXIDE- IMMERSING RETENTION CONTAINING FORMING TIME THICKNESS RATIO FILM MATERIAL METHOD (HOUR) (nm) (%) EXAMPLE 1-1 PRESENT SILICON LIQUID- 1 2O 85 OXIDE PHASE EXAMPLE 1-2 PRESENT SILICON LIQUID- 2 30 92 OXIDE PHASE EXAMPLE 1-3 PRESENT SILICON LIQUID- 3 40 92 OXIDE PHASE EXAMPLE 1-4 PRESENT SILICON LIQUID- 6 50 93 OXIDE PHASE EXAMLPE 1-5 PRESENT SILICON LIQUID- 21 100 92 OXIDE PHASE EXAMPLE 1-6 PRESENT TINOXIDE LIQUID- 3 2O 91 PHASE EXAMPLE 1-7 PRESENT GERMANIUM LIQUID- 3 2O 91 OXID PHASE COMPARATIVE ABSENT 76 EXAMPLE 1-1 COMPARATIVE PRESENT SILICON WAPOR- 50 76 EXAMPLE 1-2 OXIDE PHASE

Moreover, the immersing time was 1 hour in Example 1-1, 2 Moreover, lithium carbonate (LiCO) and cobalt carbon hours in Example 1-2, 3 hours in Example 1-3, 6 hours in ate (CoCO) were mixed at a molar ratio of LiCO: Example 1-4, and 21 hours in Example 1-5. After that, the CoCO=0.5:1, and the mixture was fired in air at 900° C. for anode current collector 52A was cleaned with water, and 5 hours to obtain lithium cobalt complex oxide (LiCoO). dried under reduced pressure to form the anode 52. Next, after 91 parts by weight of the lithium cobalt complex Moreover, in Example 1-6, the anode current collector 52A oxide, 6 parts by weight of graphite as an electrical conductor on which the anode active material layer 52B was immersed and 3 parts by weight of polyvinylidene fluoride as a binder in a solution formed by dissolving aluminum chloride as an were mixed to form a cathode mixture, the cathode mixture anion trapping agent in hexafluorostannic acid as a fluoride was dispersed in N-methyl-2-pyrrolidone as a solvent to form complex so as to deposit the oxide-containing film 52D made cathode mixture slurry. Next, after the cathode mixture slurry of tin oxide on a region in contact with the electrolytic Solu was uniformly applied to a cathode current collector 51A US 8,932,761 B2 29 30 made of aluminum foil with a thickness of 20 um, and was other words, it was found out that when the oxide-containing dried, the cathode mixture slurry was compression molded to film 52D made of siliconoxide, tin oxide or germanium oxide form a cathode active material layer 51B. After that, the was formed on the anode active material layer 52B by a cathode current collector 51A on which the cathode active liquid-phase method, the cycle characteristics could be material layer 51B was formed was stamped into a pellet with improved. a diameter of 15.5 nm to form the cathode 51. Next, after the formed cathode 51 and the formed anode 52 Examples 2-1 to 2-5 were positioned in the package can 54 with the separator 53 made of a microporous polypropylene film in between, and At first, 90 wt % of silicon powder with an average particle 10 diameter of 1 Lum as an anode active material and 10 wt % of the electrolytic solution was injected onto the cathode 51 and polyvinylidene fluoride as a binder were mixed to form a the anode 52, and the package cup 55 was put onto the mixture, and the mixture was dispersed in N-methyl-2-pyr package can 54, and they were sealed by caulking. As the rolidone as a solvent to form anode mixture slurry. Next, after electrolytic solution, an electrolytic solution formed by dis the anode mixture slurry was uniformly applied to the anode solving 1 mol/dmoflithium hexafluorophosphate as an elec current collector 52A made of copper foil with a thickness of trolyte salt in a solvent formed by mixing 4-fluoro-1,3-diox 15 18 um, and the anode mixture slurry was dried and com olane-2-one and diethyl carbonate at a weight ratio of 1:1 was pressed, the anode mixture slurry was heated for 12 hours at used. 400° C. in a vacuum atmosphere to form the anode active As Comparative Example 1-1 relative to Examples 1-1 to material layer 52B, and the anode current collector 52A on 1-7, a secondary battery was formed as in the case of which the anode active material layer 52B was formed was Examples 1-1 to 1-7, except that the oxide-containing film stamped into a pellet with a diameter of 16 mm. Next, the was not arranged. Moreover, as Comparative Example 1-2, a anode current collector 52A on which the anode active mate secondary battery was formed as in the case of Examples 1-1 rial layer 52B was formed was immersed in a solution formed by dissolving boric acid in hexafluorosilicic acid as in the case to 1-7, except that an anode which was formed by forming the of Examples 1-1 to 1-5, thereby the oxide-containing film anode active material layer by evaporating silicon on the made of silicon oxide (SiO2) was deposited on a region in anode current collector by an electron beam evaporation 25 contact with the electrolytic solution of the surface of each method, and then laminating a coating film 152E made of anode active material particle made of silicon. At that time, silicon oxide with a thickness of 50 nm by a vapor-phase the concentrations of hexafluorosilicic acid and boric acid method as shown in FIG. 8 was used. When the anode were 2 mol/dm and 0.028 mol/dm, respectively. The obtained in Comparative Example 1-2 was observed, it was immersing time was 1 hour in Example 2-1, 2 hours in confirmed that the coating film 152E was formed only on the 30 Example 2-2, 3 hours in Example 2-3, 6 hours in Exhale 2-4 top surface of the anode active material layer 152B, and the and 21 hours in Example 2-5. After that, the anode current surfaces of anode active material particles 152C in the interior collector 52A was cleaned with water, and dried under of the anode active material layer 152B were exposed. reduced pressure to form the anode 52. The cycle characteristics of the formed secondary batteries After the anode 52 was formed, secondary batteries using of Examples 1-1 to 1-7 and Comparative Examples 1-1 and 35 the anode 52 were formed as in the case of Examples 1-1 to 1-2 were determined. The cycle characteristics were deter 1-5. mined by performing 100 cycles of charge and discharge at As Comparative Example 2-1 relative to Examples 2-1 to 23°C., and then determining the discharge capacity retention 2-5, a secondary battery was formed as in the case of ratio (%) in the 100th cycle in the case where the discharge Examples 2-1 to 2-5, except that the oxide-containing film 40 was not arranged. Moreover, as Comparative Example 2-2, a capacity in the second cycle was 100. At that time, after the secondary battery was formed as in the case of Examples 2-1 secondary batteries were charged at a constant current density to 2-5, except a coating film made of siliconoxide was formed of 1 mA/cm until the battery voltage reached 4.2 V, the by heating silicon powder with an average particle diameter secondary batteries were charged at a constant Voltage of 4.2 of 1 um at 300°C. in an argon gas including 5% of oxygen to V until the current density reached 0.02 mA/cm, and the oxidize the silicon powder, and the anode was formed through secondary batteries were discharged at a constant current 45 the use of the powder. When the anode obtained in Compara density of 1 mA/cm until the battery voltage reached 2.5 V. tive Example 2-2 was observed by an SEM, the coating film The results are shown in Table 1. was not observed, and the thickness thereof was unknown. As shown in Table 1, in Examples 1-1 to 1-7 in which the Therefore, it was considered that the configuration of a film oxide-containing film 52D was formed by a liquid-phase formed by a liquid-phase method was different from that of a method, the discharge capacity retention ratio was improved, 50 film formed by a vapor-phase method. compared to Comparative Example 1-1 in which the oxide The cycle characteristics of the formed secondary batteries containing film was not formed and Comparative Example of Examples 2-1 to 2-5 and Comparative Examples 2-1 and 1-2 in which the coating film 152E was laminated on the 2-2 were determined as in the case of Examples 1-1 to 1-7. anode active material layer 152B by a vapor-phase method. In The results are shown in Table 2. TABLE 2 Battery shape: coin type Anode active material: silicon (coating

DISCHARGE CAPACITY OXIDE- IMMERSING RETENTION CONTAINING FORMING TIME THICKNESS RATIO FILM MATERIAL METHOD (HOUR) (nm) (%)

EXAMPLE 2-1 PRESENT SILICON LIQUID- 1 2O 70 OXIDE PHASE US 8,932,761 B2 31 32 TABLE 2-continued Battery shape: coin type Anode active material: silicon (coating DISCHARGE CAPACITY OXIDE- IMMERSING RETENTION CONTAINING FORMING TIME THICKNESS RATIO FILM MATERIAL METHOD (HOUR) (nm) (%) EXAMPLE 2-2 PRESENT SILICON LIQUID- 2 30 71 OXIDE PHASE EXAMPLE 2-3 PRESENT SILICON LIQUID- 3 40 71 OXIDE PHASE EXAMPLE 2-4 PRESENT SILICON LIQUID- 6 50 70 OXIDE PHASE EXAMLPE 2-S PRESENT SILICON LIQUID- 21 100 71 OXIDE PHASE COMPARATIVE ABSENT 69 EXAMPLE 2-1 COMPARATIVE PRESENT SILICON THERMAL 65 EXAMPLE 2-2 OXIDE OXIDATION

As shown in Table 2, the same results as those in Examples Example 3-2, and 6 hours in Example 3-3. After that, the 1-1 to were obtained. More specifically, it was found out that anode current collector 52A was cleaned with water, and dried under reduced pressure to form the anode 52. in the case where the oxide-containing film made of silicon The SnCoC-containing material was synthesized by mix oxide was formed on a region in contact with the electrolytic 25 ing tin-cobalt-indium alloy powder and carbon powder, and Solution of the Surface of each anode active material particle inducing a mechanochemical reaction between them. When including silicon as an element by a liquid-phase method, the composition of the obtained SnCoC-containing material even if the method of forming the anode active material layer was analyzed, the tin content was 48 wt %, the cobalt content 52B was changed, the cycle characteristics could be was 23 wt %, and the carbon content was 20 wt %, and the improved. 30 ratio of cobalt to the total of tin and cobalt Co/(Sn+Co) was 32.4 wt %. The carbon content was measured by a carbon/ sulfur analyzer, and the contents of tin and cobalt were mea Examples 3-1 to 3-3 sured by ICP (Inductively Coupled Plasma) emission spec trometry. Moreover, when X-ray diffraction was performed 80 parts by weight of the SnCoC-containing material as an on the obtained SnCoC-containing material, a diffraction anode active material, 11 parts by weight of graphite and 1 35 peak having a broad half-width in which the diffraction angle part by weight of acetylene black as electrical conductors and 20 was 1.0° or more was observed within a range of the 8 parts by weight of polyvinylidene fluoride as a binder were diffraction angle 20=20° to 50°. Further, when the XPS mea mixed to form a mixture, and the mixture was dispersed in Surement was performed on the obtained SnCoC-containing N-methyl-2-pyrrolidone as a solvent to form anode mixture material, the peak P1 shown in FIG.9 was obtained. When the slurry. Next, after the anode mixture slurry was uniformly 40 peak P1 was analyzed, a peak P2 of Surface contamination applied to the anode current collector 52A made of copperfoil carbon and a peak P3 of C1s in the SnCoC-containing mate with a thickness of 10 Jum, and was dried, the anode mixture rial on a lower energy side than the peak P2 were obtained. slurry was compression molded to form the anode active The peak P3 was obtained in a region lower than 284.5 eV. In material layer 52B, and the anode current collector 52A on which the anode active material layer 52B was formed was other words, it was confirmed that carbon included in the stamped into a pellet with a diameter of 16 mm. Next, the 45 SnCoC-containing material was bonded to another element. anode current collector 52A on which the anode active mate After the anode 52 was formed, secondary batteries were rial layer 52B was formed was immersed in a solution formed formed through the use of the anode 52 as in the case of by dissolving boric acid in hexafluorosilicic acid as in the case Examples 1-1 to 1-5. of Examples 1-1 to 1-5 to deposit the oxide-containing film As Comparative Example 2-1 relative to Examples 3-1 to made of silicon oxide (SiO) on a region in contact with the 50 3-3, a secondary battery was formed as in the case of electrolytic solution of the surface of each anode active mate Examples 3-1 to 3-3, except that the oxide-containing film rial particle made of the SnCoC-containing material. At that was not arranged. time, the concentrations of hexafluorosilicic acid and boric The cycle characteristics of the formed secondary batteries acid were 0.1 mol/dm and 0.028 mol/dm, respectively. The of Examples 3-1 to 3-3 and Comparative Example 3-1 were immersing time was 1 hour in Example 3-1, 3 hours in determined. The results are shown in Table 3. TABLE 3 Battery shape: coin type Anode active material: SnCOC-containing material

DISCHARGE CAPACITY OXIDE IMMERSING RETENTION CONTAINING FORMING TIME THICKNESS RATIO FILM MATERIAL METHOD (HOUR) (nm) (%) EXAMPLE 3-1 PRESENT SILICON LIQUID- 1 30 91 OXIDE PHASE US 8,932,761 B2 33 34 TABLE 3-continued Battery shape: coin type Anode active material: SnCoC-containing material DISCHARGE CAPACITY OXIDE- IMMERSING RETENTION CONTAINING FORMING TIME THICKNESS RATIO FILM MATERIAL METHOD (HOUR) (nm) (%) EXAMPLE 3-2 PRESENT SILICON LIQUID- 3 50 92 OXIDE PHASE EXAMLPE 3-3 PRESENT SILICON LIQUID- 6 100 91 OXIDE PHASE COMPARATIVE ABSENT 90 EXAMPLE 3-1

As shown in Table 3, the same results as those in Examples Solution of the Surface of each anode active material particle 1-1 to 1-5 were obtained. More specifically, it was found out including at least one of silicon and tin as an element by a that when the oxide-containing film made of silicon oxide liquid-phase method, the cycle characteristics could be was formed on a region in contact with the electrolytic solu- 20 improved. tion of the surface of each anode active material particle including tin as an element by a liquid-phase method, the Examples 5-1 to 5-3 cycle characteristics could be improved. Laminate film type secondary batteries shown in FIGS. 3 Examples 4-1 to 4-3 25 and 4 were formed. At first, the cathode 33 and the anode 34 were formed as in the case of Examples 1-1, 1-3 and 1-4. The Cylindrical type secondary batteries shown in FIGS. 1 and anode 34 was formed by forming the anode active material 2 were formed. At that time, the cathode 21 and the anode 22 layer 34B made of silicon by an electron beam evaporation were formed as in the case of Examples 1-1, 1-3 and 1-4. The method, and then forming the oxide-containing film made of anode 22 was formed by forming the anode active material 30 silicon oxide. layer 22B made of silicon by an electron beam evaporation Next, an electrolytic solution was formed by mixing method, and then forming the oxide-containing film made of 4-fluoro-1,3-dioxolane-2-one and propylene carbonate at a silicon oxide. As the separator 23, a microporous polypropy weight ratio of 1:1 to form a solvent, and dissolving 1 mol/ lene film with a thickness of 25 um was used, and the elec dm of lithium hexafluorophosphate as an electrolyte salt in trolytic solution was the same as that in Examples 1-1 to 1-7. 35 the solvent. Next, as a polymer compound, a copolymer As Comparative Example 4-1 relative to Examples 4-1 to formed by block copolymerizing vinylidene fluoride and 4-3, a secondary battery was formed as in the case of hexafluoropropylene at a weight ratio of vinylidene fluoride: Examples 4-1 to 4-3, except that the oxide-containing film hexafluoropropylene=93:7 was prepared, and the polymer was not arranged. compound and the formed electrolytic solution were mixed The cycle characteristics of the formed secondary batteries 40 with a mixture solvent to form a precursor solution. After that, of Examples 4-1 to 4-3 and Comparative Example 4-1 were the formed precursor solution was applied to the cathode 33 determined as in the case of Examples 1-1 to 1-7. The results and the anode 34, and the mixture solvent was volatilized to are shown in Table 4. form the gel electrolyte layer 36. TABLE 4 Battery shape: cylindrical type Anode active material: Silicon (electron beam evaporation DISCHARGE CAPACITY OXIDE- IMMERSING RETENTION CONTAINING FORMING TIME THICKNESS RATIO FILM MATERIAL METHOD (HOUR) (nm) (%) EXAMPLE 4-1 PRESENT SILICON LIQUID- 1 2O 83 OXIDE PHASE EXAMPLE 4-2 PRESENT SILICON LIQUID- 3 40 85 OXIDE PHASE EXAMLPE 4-3 PRESENT SILICON LIQUID- 6 50 88 OXIDE PHASE COMPARATIVE ABSENT 74 EXAMPLE 4-1

As shown in Table 4, the same results as those in Examples Next, the cathode lead made of aluminum was attached to 1-1 to 1-5 were obtained. More specifically, it was found out the cathode 33, and the anode lead 32 made of nickel was that even in the case of a secondary battery with another 65 attached to the anode 34, and after the cathode 33 and the shape, when the oxide-containing film made of silicon oxide anode 34 were laminated and spirally wound with the sepa was arranged on a region in contact with the electrolytic rator 35 made of polyethylene with a thickness of 25 um in US 8,932,761 B2 35 36 between, they were sealed in the package members 40 made the Sol-gel method, at first, 25 g of tetraethoxysilane was of a laminate film under reduced pressure to form each of the added to a solution formed by mixing 75.2 g of ethanol, 23.5 secondary batteries. g of water, 0.3 g of hydrochloric acid, 0.9 g of lithium As Comparative Example 5-1 relative to Example 5-1 to hexafluorophosphate, and was stirred for 2 hours to form a 5-3, a secondary battery was formed as in the case of 5 treatment solution. However, in Example 6-9, lithium Examples 5-1 to 5-3, except that the oxide-containing film hexafluorophosphate was not added in the treatment solution. was not arranged. Next, after the anode current collector 34A on which the The cycle characteristics of the formed secondary batteries anode active material layer 34B was formed was immersed in of Examples 5-1 to 5-3 and Comparative Example 5-1 were and taken out of the treatment Solution, and a solvent such as determined as in the case of Examples 1-1 to 1-7. The results 10 ethanol was sufficiently volatilized, the anode current collec are shown in Table 5. tor 34A was fired for 1 hour at 200°C. Thereby, as shown in TABLE 5 Battery shape: laminate type Anode active material: silicon (electron beam evaporation DISCHARGE CAPACITY OXIDE- IMMERSING RETENTION CONTAINING FORMING TIME THICKNESS RATIO FILM MATERIAL METHOD (HOUR) (nm) (%) EXAMPLE S-1 PRESENT SILICON LIQUID- 1 2O 84 OXIDE PHASE EXAMPLES-2 PRESENT SILICON LIQUID- 3 40 86 OXIDE PHASE EXAMLPES-3 PRESENT SILICON LIQUID- 6 50 86 OXIDE PHASE COMPARATIVE ABSENT 72 EXAMPLE S-1

As shown in Table 5, the same results as those in Examples 30 FIG. 7, the oxide-containing film 34D made of silicon oxide 1-1 to 1-5 were obtained. More specifically, it was found out (SiO) was formed on a region in contact with the electrolytic that even in the case where a gel electrolyte was used, when Solution of the Surface of each anode active material particle the oxide-containing film made of silicon oxide was arranged 34C to obtain the anode active material layer 34B. The thick on a region in contact with the electrolyte of the surface of ness of the oxide-containing film 34D fell within a range from each anode active material particle including at least one of 35 30 nm to 300 nm. Finally, the anode lead 32 made of nickel silicon and tin as an element by a liquid-phase method, the was attached to an end of the anode current collector 34A. cycle characteristics could be improved. Next, after a solvent formed by mixing a base including a mixture of ethylene carbonate (EC) and diethyl carbonate Examples 6-1 to 6-9 40 (DEC) at a weight ratio of 1:1 and 1 wt % of each of various additives shown in Table 6 (to be mentioned later) relative to Laminate film type secondary batteries shown in FIGS. 3 the base was prepared, 1 mol/kg of lithium hexafluorophos and 4 were formed. phate as an electrolyte salt was dissolved in the solvent to At first, the cathode 33 was formed. More specifically, form the electrolytic solution. However, in Example 6-1, the lithium carbonate (Li-CO) and cobalt carbonate (CoCO) 45 additives were not used. In Table 6, VC indicates vinylene were mixed at a molar ratio of LiCO:CoCO=0.5:1 and the carbonate (1,3-dioxol-2-one), VEC indicates vinyl ethylene mixture was fired in air at 900° C. for 5 hours to obtainlithium carbonate (4-vinyl-1,3-dioxolane-2-one), FEC indicates cobalt complex oxide (LiCoO). Next, after 91 parts by fluoroethylene carbonate (4-fluoro-1,3-dioxolane-2-one), weight of the lithium cobalt complex oxide, 6 parts by weight DFEC indicates difluoroethylene carbonate (4,5-difluoro-1, of graphite as an electrical conductor and 3 parts by weight of 50 3-dioxolane-2-one), PRS indicates propene sultone, SCAH polyvinylidene fluoride as a binder were mixed to form a indicates succinic anhydride, and SBAH indicates sulfoben cathode mixture, the cathode mixture was dispersed in N-me Zoic anhydride. After the electrolytic solution was formed, a thyl-2-pyrrolidone as a solvent to form cathode mixture copolymer formed by block copolymerizing vinylidene fluo slurry. Next, after the cathode mixture slurry was uniformly ride and hexafluoropropylene at a weight ratio of vinylidene applied to both sides of the cathode current collector 33A 55 fluoride:hexafluoropropylene=93.7 was prepared as a poly made of aluminum foil with a thickness of 12 um, and was dried, the cathode mixture slurry was compression molded by mer compound, and the polymer compound and the formed a roller press to form the cathode active material layer 33B. electrolytic solution were mixed with a predetermined mix After that, the cathode lead 31 made of aluminum was ture solvent to form a precursor solution. After that, the attached to an end of the cathode current collector 33A. 60 formed precursor solution was applied to the cathode 33 and Next, the anode 34 was formed. More specifically, at first, the anode 34, and the mixture solvent was volatilized to form a plurality of anode active material particles 34C made of the gel electrolyte layer 36. silicon were formed on the anode current collector 34A made Next, after the cathode 33 and the anode 34 were laminated of copper foil with a thickness of 10 um by an electron beam and spirally wound with the separator 35 made of polyethyl evaporation method, and after that, the oxide-containing film 65 ene with a thickness of 25um in between, they were sealed in 34D was selectively formed on the surfaces of the anode the package members 40 made of a laminate film under active material particles 34C by a sol-gel method. To perform reduced pressure to form each of the secondary batteries. US 8,932,761 B2 37 38 Moreover, as Comparative Examples 6-1 and 6-2, second electrolytic plating method while Supplying air in a plating ary batteries were formed as in the case of Examples 6-1 and bath so that gaps between the anode active material particles 6-5, except that the oxide-containing film was not arranged. The cycle characteristics of the formed secondary batteries 34C covered with the oxide-containing film 34D were filled of Examples 6-1 to 6-9 and Comparative Examples 6-1 and 5 with cobalt. At that time, as a plating solution, a cobalt plating 6-2 were determined. The cycle characteristics were deter solution of Japan Pure Chemical Co., Ltd was used, and the mined by performing 100 cycles of charge and discharge at current density was 2A/dm to 5A/dm, and the plating speed 23°C., and then determining the discharge capacity retention ratio (%) in the 100th cycle in the case where the discharge was 10 nm/sec. capacity in the second cycle was 100. At that time, after the 10 secondary batteries were charged at a constant current density Example 7-2 of 1 mA/cm until the battery voltage reached 4.2 V, the secondary batteries were charged at a constant Voltage of 4.2 V until the current density reached mA/cm, and the second A secondary battery of Example 7-2 was formed as in the ary batteries were discharged at a constant current density of 15 case of Example 6-5, except that the oxide-containing film 1 mA/cm until the battery voltage reached 2.5V. The results 34D was formed by a liquid-phase deposition method as in are shown in Table 6. the case of Example 1-3.

TABLE 6 Battery shape: laminate type Anode active material: silicon (electron beam evaporation) Method of forming oxide-containing film: Sol-gel method

DISCHARGE CAPACITY OXIDE- RETENTION CONTAINING SOLVENT OTHER RATIO

FILM MATERIAL BASE ADDITIVE CONDITION (%)

EXAMPLE 6-1 SILICON ECAND - 42 OXIDE DEC EXAMPLE 6-2 PRESENT SILICON VC 53 OXIDE EXAMPLE 6-3 SILICON VEC 51 OXIDE EXAMPLE 6-4 SILICON FEC 51 OXIDE EXAMPLE 6-5 PRESENT SILICON DFEC 68 OXIDE EXAMPLE 6-6 PRESENT SILICON PRS 43 OXIDE EXAMPLE 6-7 PRESENT SILICON SCAH 44 OXIDE EXAMPLE 6-8 SILICON SBAH 45 OXIDE EXAMLPE 6-9 PRESENT SILICON *1 30 OXIDE COMPARATIVE ABSENT ECAND - 23 EXAMPLE 6-1 DEC COMPARATIVE ABSENT DFEC 44 EXAMPLE 6-2 * 1: LiPF was not added in the treatment solution which was used to form the oxide-containing film.

As shown in Table 6, it was found out that even in the case Example 7-3 where the oxide-containing film made of silicon oxide was formed on a region in contact with the electrolyte of the 55 A secondary battery of Example 7-3 was formed as in the Surface of each anode active material particle by a sol-gel case of Example 7-1, except that the oxide-containing film method, the cycle characteristics could be improved. More over, it was confirmed by comparison between Example 6-1 34D was formed by a liquid-phase deposition method as in and Example 6-9 that when LiPF was added in the treatment the case of Example 1-3. solution of the sol-gel method which was used to form the 60 Moreover, as Comparative Example 7-1, a secondary bat oxide-containing film, the cycle characteristics could be fur tery was formed as in the case of Examples 7-1 and 7-3, ther improved. except that the oxide-containing film was not arranged. The cycle characteristics of the formed secondary batteries Example 7-1 of Examples 7-1 to 7-3 and Comparative Example 7-1 were 65 determined as in the case of Examples 6-1 to 6-9. The results A secondary battery of Example 7-1 was formed as in the are shown in Table 7 together with the results of Example 6-5 case of Example 6-5, except that cobalt was deposited by a and Comparative Example 6-2. US 8,932,761 B2 39 40 TABLE 7 Battery shape: laminate type Anode active material: silicon (electron beam evaporation DISCHARGE CAPACITY OXIDE- RETENTION CONTAINING FORMING SOLVENT Co RATIO

FILM MATERIAL METHOD BASE ADDITIVE PLATING (%)

EXAMPLE 6-5 PRESENT SILICON SOL-GEL ECAND DFEC ABSENT 68 OXIDE DEC EXAMPLE 7-1 PRESENT SILICON SOL-GEL DFEC PRESENT 74 OXIDE EXAMPLE 7-2 PRESENT SILICON LIQUID- DFEC ABSENT 69 OXIDE PHASE DEPOSITION EXAMLPE 7-3 PRESENT SILICON LIQUID- DFEC PRESENT 75 OXIDE PHASE DEPOSITION COMPARATIVE ABSENT ECAND DFEC ABSENT 44 EXAMPLE 6-2 DEC COMPARATIVE ABSENT DFEC PRESENT 46 EXAMPLE 7-1

As shown in Table 7, it was confirmed by comparison which 0.9 mol/kg of LiPF and 0.1 mol/kg of the compound between Examples 6-5 and 7-1 or comparison between 25 represented by Chemical Formula 9(2) were dissolved as Examples 7-2 and 7-3 that when gaps between the adjacent electrolyte salts was used. anode active material particles were filled with a metal including a metal element not alloyed with an electrode reac Example 8-4 tant, the cycle characteristics could be further improved. Moreover, it was confirmed by comparison between 30 Examples 7-1 and 7-3 and Comparative Example 7-1 that A secondary battery of Example 8-4 was formed as in the when the gaps were filled with the above-described metal case of Example 6-1, except that an electrolytic solution in while forming the oxide-containing film 34D, the cycle char which 0.9 mol/kg of LiPF and 0.1 mol/kg of the compound acteristics could be further improved. represented by Chemical Formula 13(2) were dissolved as Example 8-1 35 electrolyte salts was used. Example 8-5 A secondary battery of Example 8-1 was formed as in the case of Example 6-1, except that an electrolytic solution in which 0.9 mol/kg of LiPF and 0.1 mol/kg of LiBF were A secondary battery of Example 8-5 was formed as in the 40 case of Example 6-1, except that an electrolytic solution in dissolved as electrolyte salts was used. which 0.9 mol/kg of LiPF, 0.05 mol/kg of the compound Example 8-2 represented by Chemical Formula 8(6) and 0.05 mol/kg of the compound represented by Chemical Formula 13(2) were dis A secondary battery of Example 8-2 was formed as in the Solved as electrolyte salts was used. case of Example 6-1, except that an electrolytic solution in 45 Moreover, as Comparative Example 8-1, a secondary bat which 0.9 mol/kg of LiPF and 0.1 mol/kg of the compound tery was formed as in the case of Example 8-2, except that the represented by Chemical Formula 8(6) were dissolved as oxide-containing film was not arranged. electrolyte salts was used. The cycle characteristics of the formed secondary batteries Example 8-3 of Examples 8-1 to 8-5 and Comparative Example 8-1 were 50 determined as in the case of Examples 6-1 to 6-9. The results A secondary battery of Example 8-3 was formed as in the are shown in Table 8 together with the results of Example 6-1 case of Example 6-1, except that an electrolytic solution in and Comparative Example 6-1. TABLE 8 Battery shape: laminate type Anode active material: silicon (electron beam evaporation) Oxide-containing film: silicon oxide (sol-gel method

DISCHARGE CAPACITY OXIDE- RETENTION CONTAINING RATIO FILM ELECTROLYTE SALT (%) EXAMPLE 6-1 PRESENT LiPF 42 1.0 mol/kg EXAMPLE 8-1 PRESENT LiPF LiBF 43 0.9 mol/kg 0.1 mol/kg US 8,932,761 B2 41 42 TABLE 8-continued Battery shape: laminate type Anode active material: silicon (electron beam evaporation) Oxide-containing film: silicon oxide (sol-gel method

DISCHARGE CAPACITY OXIDE- RETENTION CONTAINING RATIO FILM ELECTROLYTE SALT (%) EXAMPLE 8-2 PRESENT CHEMICAL FORMULA 8(6) 46 0.1 mol/kg EXAMPLE 8-3 PRESENT CHEMICAL FORMULA 9(2) 48 0.1 mol/kg EXAMPLE 8-4 PRESENT CHEMICAL FORMULA 13(2) 43 0.1 mol/kg EXAMPLE 8-5 PRESENT LiPF CHEMICAL CHEMICAL 48 0.8 mol/kg FORMULA 8(6) FORMULA 13(2) 0.05 mol/kg 0.05 mol/kg COMPARATIVE ABSENT LiPF 23 EXAMPLE 6-1 1.0 mol/kg COMPARATIVE ABSENT LiPF CHEMICAL FORMULA 8(6) 32 EXAMPLE 8-1 0.9 mol/kg 0.1 mol/kg

As shown in Table 8, it was found out by comparison concentrations of hexafluorosilicic acid and boric acid were 2 between Example 6-1 and Examples 8-1 to 8-5 that when mol/dm and 0.028 mol/dm, respectively. Moreover, the LiBF, the compound represented by Chemical Formula 8(6), 25 immersing time was 1 hour in Example 9-1, 2 hours in the compound represented by Chemical Formula 9(2), the Example 9-2, 3 hours in Example 9-3, 6 hours in Example compound represented by Chemical Formula 13(2) or the like 9-4, and 21 hours in Example 9-5. After that, the anode was included as the electrolyte salt in addition to LiPF, current collector 52A was cleaned with water, and dried under higher cycle characteristics could be obtained. Moreover, it reduced pressure to form the anode 52. was confirmed by comparison between Example 8-1 and 30 Moreover, in Example 9-6, the anode current collector 52A Comparative Example 8-1 that even in the case where another on which the anode active material layer 52B was formed was electrolyte salt was added to LiPF, an effect of improving the immersed in a solution formed by dissolving aluminum chlo cycle characteristics by arranging the oxide-containing film ride as an anion trapping agent in hexafluorostannic acid as could be obtained. fluoride complex, thereby a coating film including tin oxide and a fluoride of tin was deposited on the surface of the anode Examples 9-1 to 9-7 35 active material made of silicon. At that time, the concentra Coin type secondary batteries shown in FIG. 6 were tions of hexafluorostannic acid and aluminum chloride were formed. The secondary batteries had a configuration in which 0.17 mol/dm and 0.07 mol/dm, respectively, and the the cathode 51 and the anode 52 were laminated with the immersing time was 3 hours. After that, the anode current separator 53 impregnated with the electrolytic solution in collector 52A was cleaned with water, and dried under between, and they were sandwiched between the package can 40 reduced pressure to form the anode 52. 54 and the package cup 55, and the package can 54 and the Further, in Example 9-7, the anode current collector 52A package cup 55 were caulked by the gasket 56. on which the anode active material layer 52B was formed was At first, after the anode active material layer 52B was immersed in a solution formed by dissolving aluminum chlo formed on the anode current collector 52A made of copper ride as an anion trapping agent in hexafluorogermanic acid as foil with a thickness of 10 um by evaporating silicon by an a fluoride complex, thereby a coating film including germa electronbeam evaporation method, the anode current collec 45 nium oxide and a fluoride of germanium was deposited on the tor 52A on which the anode active material layer 52B was surface of the anode active material made of silicon. At that formed was stamped into a pellet with a diameter of 16 mm. time, the concentrations of hexafluorogermanic acid and alu Next, in Examples 9-1 to 9-5, the anode current collector minum chloride were 0.17 mol/dm and 0.05 mol/dm. 52A on which the anode active material layer 52B was formed respectively, and the immersing time was 3 hours. After that, was immersed in a solution formed by dissolving boric acidas 50 the anode current collector 52A was cleaned with water, and an anion trapping agent in hexafluorosilicic acid as a fluoride dried under reduced pressure to form the anode 52. complex, thereby a coating film including silicon oxide The ratio of elements in the coating film was determined by (SiO) and a fluoride of silicon was deposited on the surface XPS through the use of the formed anode 52. The results are of the anode active material made of silicon. At that time, the shown in Table 9. TABLE 9 Battery shape: coin type Anode active material: silicon (electron beam evaporation DISCHARGE CAPACITY RETENTION IMMERSING XPS (at 90 RATIO

TIME Si O F Sn GE FS FS FiGe (%)

EXAMPLE 9-1 1 HOUR 28.8 601 3.5 - — 0.12 — 85 EXAMPLE 9-2 2 HOURS 29.0 61.8 3.6 – — 0.12 — 92 US 8,932,761 B2 43 44 TABLE 9-continued Battery shape: coin type Anode active material: silicon (electron beam evaporation DISCHARGE CAPACITY RETENTION IMMERSING XPS (at 90 RATIO TIME Si O F Sn GE FS F.S FGe. (%)

EXAMPLE 9-3 3HOURS 29.4 63.O 3.7 - — 0.13 92 EXAMPLE 9-4 6 HOURS 28.5 6.O-O 4.0 - — 0.14 93 EXAMPLE 9-5 21 HOURS 280 58.3 6.0 - — 0.21 92 EXAMPLE 9-6 3HOURS 23.0 56.O 20 15.3 - 91 EXAMPLE 9-7 3HOURS 30.0 55.5 1.5 - 10.3 - 91 COMPARATIVE 44.4 49.0 O 76 EXAMPLE 9-1 COMPARATIVE 30.5 57.5 O 76 EXAMPLE 9-2

Moreover, lithium carbonate (LiCO) and cobalt carbon the second cycle was 100. At that time, after the secondary ate (CoCO) were mixed at a molar ratio of LiCO: batteries were charged at a constant current density of 1 CoCO=0.5:1, and the mixture was fired in air for 5 hours at mA/cm until the battery voltage reached 4.2V, the secondary 900° C. to obtain lithium cobalt complex oxide (LiCoO) as batteries were charged at a constant voltage of 4.2V until the the cathode active material. Next, after 91 parts by weight of 25 current density reached 0.02 mA/cm, and the secondary the lithium cobalt complex oxide, 6 parts by weight of graph batteries were discharged at a constant current density of 1 ite as an electrical conductor and 3 parts by weight of poly mA/cm until the battery voltage reached 2.5 V. The results vinylidene fluoride as a binder were mixed to form a cathode are shown in Table 9. mixture, the cathode mixture was dispersed in N-methyl-2- 30 As shown in Table 9, it was confirmed by the results pyrrolidone as a solvent to form cathode mixture slurry. Next, obtained by XPS that in Examples 9-1 to 9-5, silicon, oxygen after the cathode mixture slurry was uniformly applied to the and fluorine were observed, and silicon oxide and a fluoride cathode current collector 51A made of aluminum foil with a of silicon were present. Moreover, in Example 9-6, it was thickness of 20 Jum, and was dried, the cathode mixture slurry confirmed that oxygen, fluorine and tin were observed, and tin was compression molded to form the cathode active material 35 oxide and a fluoride of tin were present. Further in Example layer 51B. After that, the cathode current collector 51A on 9-7, it was confirmed that oxygen, fluorine and germanium which the cathode active material layer 51B was formed was were observed, and germanium oxide and a fluoride of ger stamped into a pellet with a diameter of 15.5 nm to form the manium were present. cathode 51. Moreover, in Examples 9-1 to 9-7 in which a coating film Next, after the cathode 51 and the anode 52 were posi 40 including an oxide of silicon and a fluoride of silicon, a tioned in the package can 54 with the separator 53 made of a coating film including an oxide of tin and a fluoride of tin, or microporous polypropylene film in between, and the electro a coating film including an oxide of germanium and a fluoride lytic solution was injected onto the cathode 51 and the anode of germanium was formed on the Surface of anode active 52, and the package cup 55 was put onto the package can 54. material made of silicon, compared to Comparative and they were sealed by caulking. As the electrolytic solution, 45 Examples 9-1 and 9-2, the discharge capacity retention ratio an electrolytic solution formed by dissolving 1 mol/dm of was improved. lithium hexafluorophosphate as an electrolyte salt in a solvent In other words, it was found out that when a coating film formed by mixing 4-fluoro-1,3-dioxolane-2-one and diethyl including an oxide of at least one kind selected from the group carbonate at a weight ratio of 1:1 was used. consisting of silicon, germanium and tin and a halide of at As Comparative Example 9-1 relative to Examples 9-1 to 50 least one kind selected from the group consisting of silicon, 9-7, a secondary battery was formed as in the case of germanium and tin was arranged on at least a part of the Examples 9-1 to 9-7, except that a coating film including an Surface of the anode active material including silicon as an oxide of silicon, germanium or tin and a fluoride of silicon, element, the cycle characteristics could be improved. germanium or tin was not formed. Moreover, as Comparative Example 9-2, a secondary battery was formed as in the case of 55 Examples 10-1 to 10-5 Examples 9-1 to 9-7, except that an anode formed by forming the anode active material layer by evaporating silicon on the At first, 90 wt % of silicon powder with an average particle anode current collector by a electron beam evaporation diameter of 1 Lum as an anode active material and 10 wt % of method, and then forming a coating film made of silicon polyvinylidene fluoride as a binder were mixed to form a oxide on the surface of the anode active material layer by a 60 mixture, and the mixture was dispersed in N-methyl-2-pyr vapor-phase method was used. rolidone as a solvent to form anode mixture slurry. Next, after The cycle characteristics of the formed secondary batteries the anode mixture slurry was uniformly applied to the anode of Examples 9-1 to 9-7 and Comparative Examples 9-1 and current collector 52A made of copper foil with a thickness of 9-2 were determined. The cycle characteristics were deter 18 um, and the anode mixture slurry was dried and com mined by performing 100 cycles of charge and discharge at 65 pressed, the anode mixture slurry was heated for 12 hours at 23°C., and then determining the capacity retention ratio (%) 400° C. in a vacuum atmosphere to form the anode active in the 100th cycle in the case where the discharge capacity in material layer 52B, and the anode current collector 52A on US 8,932,761 B2 45 46 which the anode active material layer 52B was formed was anode mixture slurry. Next, after the anode mixture slurry was stamped into a pellet with a diameter of 16 mm. Next, the uniformly applied to the anode current collector 52A made of anode current collector 52A on which the anode active mate copper foil with a thickness of 10 Lum, and dried, the anode rial layer 52B was formed was immersed in a solution formed mixture slurry was compression molded to form the anode by dissolving boric acid in hexafluorosilicic acid as in the case 5 active material layer 52B, and the anode current collector 52A of Examples 9-1 to 9-5, thereby a coating film including on which the anode active material layer 52B was formed was silicon oxide (SiO) and a fluoride of silicon was deposited on stamped into a pellet with a diameter of 16 mm. Next, the the surface of the anode active material made of silicon. At anode current collector 52A on which the anode active mate that time, the immersing time was 1 hour in Example 10-1, 2 rial layer 52B was formed was immersed in a solution formed hours in Example 10-2, 3 hours in Example 10-3, 6 hours in 10 by dissolving boric acid in hexafluorosilicic acid as in the case Example 10-4 and 21 hours in Example 10-5. After that, the of Examples 9-1 to 9-5 to deposit a coating film including anode current collector 52A was cleaned with water, and silicon oxide (SiO) and a fluoride of silicon on the surface of dried under reduced pressure to form the anode 52. the anode active material made of the SnCoC-containing After the anode 52 was formed, secondary batteries were material. At that time, the concentrations of hexafluorosilicic formed through the use of the anode 52 as in the case of 15 acid and boric acid were 0.1 mol/l and 0.028 mol/l, respec Examples 9-1 to 9-5. tively. The immersing time was 1 hour in Example 11-1, 3 As Comparative Example 10-1 relative to Examples 10-1 hours in Example 11-2 and 6 hours in Example 11-3. After to 10-5, a secondary battery was formed as in the case of that, the anode current collector 52A on which the anode Examples 10-1 to 10-5, except that a coating film including an active material layer 52B was formed was cleaned with water, oxide of silicon and a fluoride of silicon was not formed. and dried under reduced pressure to form the anode 52. Moreover, as Comparative Example 10-2, a secondary bat The SnCoC-containing material was synthesized by mix tery was formed as in the case of Examples 10-1 to 10-5, ing tin-cobalt-indium alloy powder and carbon powder, and except that an anode in which a coating film made of silicon inducing a mechanochemical reaction between them. When oxide was formed by heating the surface of silicon powder the composition of the obtained SnCoC-containing material with an average particle diameter of 1 um in air at 1000°C. to 25 was analyzed, the tin content was 48 wt %, the cobalt content oxidize the silicon powder was used. was 23 wt %, and the carbon content was 20 wt %, and the The cycle characteristics of the secondary batteries of ratio of cobalt to the total of tin and cobalt Co/(Sn+Co) was Examples 10-1 to 10-5 and Comparative Examples 10-1 and 32.4 wt %. The carbon content was measured by a carbon/ 10-2 were determined as in the case of Examples 9-1 to 9-7. Sulfur analyzer, and the contents of tin and cobalt were mea The results are shown in Table 10. 30 sured by ICP (Inductively Coupled Plasma) emission spec trometry. Moreover, when X-ray diffraction was performed TABLE 10 on the obtained SnCoC-containing material, a diffraction peak having a broad half-width in which the diffraction angle Battery shape: coin type 20 was 1.0° or more was observed within a range of the Anode active material: silicon (coating 35 diffraction angle 20=20° to 50°. Further, when the XPS mea DISCHARGE Surement was performed on the obtained SnCoC-containing CAPACITY material, the peak P1 shown in FIG.9 was obtained. When the RETENTIONRATIO peak P1 was analyzed, a peak P2 of Surface contamination IMMERSING TIME (%) carbon and a peak P3 of C1s in the SnCoC-containing mate EXAMPLE 10-1 1 HOUR 70 40 rial on a lower energy side than the peak P2 were obtained. EXAMPLE 10-2 2 HOURS 71 EXAMPLE 10-3 3 HOURS 71 The peak P3 was obtained in a region lower than 284.5 eV. In EXAMPLE 10-4 6 HOURS 70 other words, it was confirmed that carbon included in the EXAMPLE 10-5 21 HOURS 71 SnCoC-containing material was bonded to another element. COMPARATIVE 69 After the anode 52 was formed, secondary batteries were EXAMPLE 10-1 45 COMPARATIVE 65 formed through the use of the anode 52 as in the case of EXAMPLE 10-2 Examples 9-1 to 9-5. As Comparative Example 11-1 relative to Example 11-1 to 11-3, a secondary battery was formed as in the case of As shown in Table 10, the same results as those in Example 11-1 to 11-3, except that a coating film including an Examples 9-1 to 9-5 were obtained. More specifically, it was 50 oxide of silicon and a fluoride of silicon was not formed. found out that in the case where a coating film including an The cycle characteristics of the secondary batteries of oxide of at least one kind selected from the group consisting Examples 11-1 to 11-3 and Comparative Example 11-1 were of silicon, germanium and tin and a halide of at least one kind determined as in the case of Examples 9-1 to 9-7. The results selected from the group consisting of silicon, germanium and are shown in Table 11. tin was arranged on at least a part of the Surface of the anode 55 active material including silicon as an element, even if the TABLE 11 method of forming the anode active material layer 52B was changed, the cycle characteristics could be improved. Battery shape: coin type Anode active material: SnCoC-containing material 60 Examples 11-1 to 11-3 DISCHARGE CAPACITY At first, 80 parts by weight of the SnCoC-containing mate RETENTIONRATIO rial as the anode active material, 11 parts by weight of graph IMMERSING TIME (%) ite and 1 part by weight of acetylene black as electrical con EXAMPLE 11-1 1 HOUR 91 ductors and 8 parts by weight of polyvinylidene fluoride as a 65 EXAMPLE 11-2 2 HOURS 92 binder were mixed to form a mixture, and the mixture was EXAMPLE 11-3 6 HOURS 91 dispersed in N-methyl-2-pyrrolidone as a solvent to form US 8,932,761 B2 47 48 TABLE 11-continued and tin was formed on at least a part of the Surface of the anode active material including at least one of silicon and tin as an Battery shape: coin type element, the cycle characteristics could be improved. Anode active material: SnCoC-containing material Examples 13-1 to 13-3 DISCHARGE CAPACITY Laminate film type secondary batteries shown in FIGS. 3 RETENTIONRATIO and 4 were formed. At first, the cathode 33 and the anode 34 IMMERSING TIME (%) were formed as in the case of Examples 9-1, 9-3 and 9–4. The COMPARATIVE 90 anode 34 was formed by forming the anode active material EXAMPLE 11-1 10 layer 34B made of silicon by an electron beam evaporation method, and then forming a coating film including silicon oxide and a fluoride of silicon. Moreover, the ratio of ele As shown in Table 11, the same results as those in ments in the coating film was determined by XPS through the Examples 9-1 to 9-5 were obtained. More specifically, it was use of the formed anode 34. The results are shown in Table 13. found out that when a coating film including an oxide of at least one kind selected from the group consisting of silicon, TABLE 13 germanium and tin and a halide of at least one kind selected from the group consisting of silicon, germanium and tin was Battery shape: laminate type arranged on at least a part of the Surface of the anode active Anode active material: silicon (electron beam evaporation material including tin as an element, the cycle characteristics DISCHARGE could be improved. CAPACITY IMMER- RETENTION Examples 12-1 to 12-3 SING XPS (at 96) RATIO TIME Si O F FAS (%) Cylindrical type secondary batteries shown in FIGS. 1 and 25 EXAMPLE 13-1 1 HOUR 28.8 60.2 3.6 O.13 84 2 were formed. At that time, the cathode 21 and the anode 22 EXAMPLE 13-2 3 HOURS 29.O 6OS 3.3 0.11 86 were formed as in the case of Examples 9-1, 9-3 and 9–4. The EXAMPLE 13-3 6 HOURS 29.1 66.9 3.7 O.13 86 anode 22 was formed by forming the anode active material COMPARATIVE 44.4 49.0 O – 72 layer 22B made of silicon by an electron beam evaporation EXAMPLE 13-1 method, and then forming a coating film including silicon 30 oxide and a fluoride of silicon. As the separator 23, a Next, an electrolytic solution was formed by mixing microporous polypropylene film with a thickness of 25 um 4-fluoro-1,3-dioxolane-2-one and propylene carbonate at a was used, and the electrolytic Solution was the same as that in weight ratio of 1:1 to form a solvent, and dissolving 1 mol/l of Examples 9-1 to 9-7. lithium hexafluorophosphate as an electrolyte salt in the sol The ratio of elements in the coating film was determined by 35 vent. Next, as a polymer compound, a copolymer formed by XPS through the use of the formed anode 22. The results are block copolymerizing vinylidene fluoride and hexafluoropro shown in Table 12. pylene at a weight ratio of vinylidene fluoride:hexafluoropro pylene=93:7 was prepared, and the polymer compound and TABLE 12 the formed electrolytic solution were mixed with a mixture solvent to form a precursor solution. After that, the formed Battery shape: cylindrical type 40 precursor solution was applied to the cathode 33 and the Anode active material: silicon (electron beam evaporation anode 34, and the mixture solvent was volatilized to form the gel electrolyte layer 36. DISCHARGE CAPACITY Next, the cathode lead 31 made of aluminum was attached IMMER- RETENTION to the cathode 33, and the anode lead 32 made of nickel was SING XPS (at 96) RATIO 45 attached to the anode 34, and after the cathode 33 and the anode 34 were laminated and spirally wound with the sepa TIME Si O F FS (%) rator 35 made of polyethylene with a thickness of 25um, they EXAMPLE 12-1 1 HOUR 28.0 60.3 3.5 0.13 83 were sealed in the package members 40 made of a laminate EXAMPLE 12-2 3 HOURS 29.6 60.8 3.8 O.13 85 film under reduced pressure to form each of the secondary EXAMPLE 12-3 6 HOURS 28.8 65.2 3.6 O.13 88 50 batteries. COMPARATIVE 44.4 49.0 O – 74 As Comparative Example 13-1 relative to Examples 13-1 EXAMPLE 12-1 to 13-3, a secondary battery was formed as in the case of Example 13-1 to 13-3, except that a coating film including an As Comparative Example 12-1 relative to Examples 12-1 oxide of silicon and a fluoride of silicon was not formed. to 12-3, a secondary battery was formed as in the case of 55 The cycle characteristics of the secondary batteries of Examples 12-1 to 12-3, except that a coating film including an Examples 13-1 to 13-3 and Comparative Example 13-1 were oxide of silicon and a fluoride of silicon was not formed. determined as in the case of Examples 9-1 to 9-7. The results are shown in Table 13. The cycle characteristics of the secondary batteries of As shown in Table 13, the same results as those in Examples 12-1 to 12-3 and Comparative Example 12-1 were Examples 9-1 to 9-5 were obtained. More specifically, it was determined as in the case of Examples 9-1 to 9-7. The results 60 found out that even in the case where a gel electrolyte was are shown in Table 12. used, when a coating film including an oxide of at least one As shown in Table 12, the same results as those in kind selected from the group consisting of silicon, germa Examples 9-1 to 9-5 were obtained. More specifically, it was nium and tin and a halide of at least one kind selected from found out that even in the case of a secondary battery with silicon, germanium and tin was formed on at least apart of the another shape, when a coating film including an oxide of at 65 Surface of the anode active material including at least one of least one kind selected from silicon, germanium and tin and a silicon and tin as an element, the cycle characteristics could halide of at least one kind selected from silicon, germanium be improved. US 8,932,761 B2 49 50 Examples 14-1 to 14-11 weight ratio of 1:1 and 1 wt % of each of various additives shown in Table 14 (to be mentioned later) relative to the base was prepared, 1 mol/kg of lithium hexafluorophosphate as an At first, the cathode 33 was formed. More specifically, electrolyte salt was dissolved in the solvent to form the elec lithium carbonate (LiCO) and cobalt carbonate (CoCO) trolytic solution. However, in Example 14-1, the additives were mixed at a molar ratio of LiCO:CoCO=0.5:1, and the were not used. In Table 14, VC indicates vinylene carbonate mixture was fired in air at 900° C. for 5 hours to obtainlithium (1,3-dioxol-2-one), VEC indicates vinyl ethylene carbonate cobalt complex oxide (LiCoO). Next, after 91 parts by (4-vinyl-1,3-dioxolane-2-one), FEC indicates fluoroethylene weight of the lithium cobalt complex oxide, 6 parts by weight carbonate (4-fluoro-1,3-dioxolane-2-one), DFEC indicates of graphite as an electrical conductor and 3 parts by weight of difluoroethylene carbonate (4,5-difluoro-1,3-dioxolane-2- polyvinylidene fluoride as a binder were mixed to form a 10 one), PRS indicates propene sultone, SCAH indicates suc cathode mixture, the cathode mixture was dispersed in N-me cinic anhydride, and SBAH indicates sulfobenzoic anhy thyl-2-pyrrolidone as a solvent to form cathode mixture dride. After the electrolytic solution was formed, as a polymer slurry. Next, after the cathode mixture slurry was uniformly compound, a copolymer formed by block copolymerizing applied to both sides of the cathode current collector 33A vinylidene fluoride and hexafluoropropylene at a weight ratio made of aluminum foil with a thickness of 12 um, and was of vinylidene fluoride:hexafluoropropylene=93:7 was pre dried, the cathode mixture slurry was compression molded by 15 pared, and the polymer compound and the electrolytic solu a roller press to form the cathode active material layer 33B. tion formed in advance were mixed with a predetermined After that, the cathode lead 31 made of aluminum was mixture solvent to form a precursor solution. After that, the attached to an end of the cathode current collector 33A by formed precursor solution was applied to the cathode 33 and welding. the anode 34, and the mixture solvent was volatilized to form Next, the anode 34 was formed. More specifically, at first, the gel electrolyte layer 36. a plurality of anode active material particles made of silicon Next, after the cathode 33 and the anode 34 were laminated were formed on the anode current collector 34A made of and spirally wound with the separator 35 made of polyethyl copper foil with a thickness of 10 um by an electron beam ene with a thickness of 25um in between, they were sealed in evaporation method, and a coating film including silicon the package members 40 made of a laminate film under oxide and a fluoride of silicon was selectively formed on the reduced pressure to form each secondary battery. surfaces of the anode active material particles to obtain the 25 anode active material layer34B. The coating film was formed Comparative Examples 14-1 to 14-3 by a sol-gel method in Examples 14-1 to 14-9. To perform the sol-gel method, at first, 25g of tetraethoxysilane was added to Moreover, as Comparative Example 14-1, a secondary bat a solution formed by mixing 75.2 g of ethanol, 23.5g of water, tery was formed as in the case of Example 14-1, except that 0.3 g of hydrochloric acid, 0.9 g of lithium hexafluorophos 30 the coating film was not arranged, and as Comparative phate, and was stirred for 2 hours to form a treatment solution. Example 14-2, a secondary battery was formed as in the case Next, after the anode current collector 34A on which the of Examples 14-5 and 14-10, except that the coating film was anode active material layer34B was formed was immersed in not arranged, and as Comparative Example 14-3, a secondary and taken out of the treatment Solution, and a solvent such as battery was formed as in the case of Examples 14-9 and ethanol was sufficiently volatilized, the anode current collec 35 14-11, except that the coating film was arranged. tor 34A was fired for 1 hour at 200° C. On the other hand, in The cycle characteristics of the secondary batteries of Examples 14-10 and 14-11, the coating film was formed by a Examples 14-1 to 14-11 and Comparative Examples 14-1 to liquid-phase deposition method as in the case of Example 9-3. 14-3 were determined. The cycle characteristics were deter The thickness of the coating film fell within a range from 30 mined by performing 100 cycles of charge and discharge at nm to 300 nm. Moreover, in Examples 14-9 and 14-11, cobalt 23°C., and then determining the capacity retention ratio (%) was deposited by an electrolytic plating method while Sup 40 in the 100th cycle in the case where the discharge capacity in plying air to a plating bath so that gaps between the anode the second cycle was 100. At that time, after the secondary active material particles covered with the coating film were batteries were charged at a constant current density of 1 filled with cobalt. At that time, as a plating solution, a cobalt mA/cm until the battery voltage reached 4.2V, the secondary plating Solution of Japan Pure Chemical Co., Ltd was used, batteries were charged at a constant voltage of 4.2V until the and the current density was 2 A/dm to 5 A/dm, and the 45 current density reached 0.02 mA/cm, and the secondary plating speed was 10 nm/sec. Finally, the anode lead 32 made batteries were discharged at a constant current density of 1 of nickel was attached to an end of the anode current collector mA/cm until the battery voltage reached 2.5V. Moreover, the 34A. ratio of elements in the coating film was determined by XPS Next, after a solvent formed by mixing a base including through the use of formed anode 34. The results are shown in ethylene carbonate (EC) and diethyl carbonate (DEC) at a Table 6. TABLE 1.4 Battery shape: laminate type Anode active material: silicon (electron beam evaporation DISCHARGE CAPACITY RETENTION FORMING XPS (at 90 SOLVENT Co RATIO

METHOD Si O F FAS BASE ADDITIVE PLATING (%)

EXMAPLE 14-1 SOL-GEL 32.7 S13 2.7 0.08 EC ABSENT 42 EXMAPLE 14-2 AND VC 53 EXMAPLE 14-3 DEC VEC 51 EXMAPLE 14-4 FEC 51 EXMAPLE 14-5 DFEC 68 EXMAPLE 14-6 PRS 43 EXMAPLE 14-7 SCAH 44 US 8,932,761 B2 51 52 TABLE 14-continued Battery shape: laminate type Anode active material: silicon (electron beam evaporation DISCHARGE CAPACITY RETENTION FORMING XPS (at 90 SOLVENT Co RATIO

METHOD Si O F FAS BASE ADDITIVE PLATING (%)

EXMAPLE 14-8 SBAH 45 EXMAPLE 14-9 DFEC PRESENT 74 EXMAPLE 14-10 LIQUID- 29.0 6O.S 3.3 0.11 EC DFEC ABSENT 69 EXMAPLE 14-11 PHASE AND PRESENT 75 DEPOSITION DEC COMPARATIVE 44.4 49.0 O — EC ABSENT 23 EXMAPLE 14-1 AND DFEC ABSENT 44 COMPARATIVE DEC DFEC PRESENT 46 EXMAIPLE 14-2 COMPARATIVE EXAMPLE 14-3

As shown in Table 14, it was confirmed from the results Example 15-3 obtained by XPS that in Examples 14-1 to 14-11, silicon, oxygen and fluorine were observed, and silicon oxide and a A secondary battery of Example 15-3 was formed as in the fluoride of silicon were present. Moreover, it was found out 25 that when the coating film including silicon oxide and a case of Example 14-1, except that an electrolytic solution in fluoride of silicon was formed on the surfaces of the anode which 0.9 mol/kg of LIPF and 0.1 mol/kg of the compound active material particles by a sol-gel method or a liquid-phase represented by Chemical Formula 9(2) as electrolyte salts deposition method, the cycle characteristics were improved. were dissolved was used. Further, it was confirmed by comparison between Example 14-5 and Example 14-9 or comparison between Example and 30 Example 15-4 Example 14-11, when gaps between adjacent anode active material particles were filled with a metal including a metal A secondary battery of Example 15-4 was formed as in the element not alloyed with an electrode reactant, the cycle case of Example 14-1, except that an electrolytic solution in characteristics were further improved. Moreover, it was con which 0.9 mol/kg of LIPF and 0.1 mol/kg of the compound firmed by comparison between Examples 14-9 and 14-11 and 35 represented by Chemical Formula 13(2) as electrolyte salts Comparative Example 14-3 that when the gaps were filled were dissolved was used. with above-described metal while forming the coating film, the cycle characteristics were further improved. Example 15-5 Example 15-1 40 A secondary battery of Example 15-5 was formed as in the case of Example 14-1, except that an electrolytic solution in A secondary battery of Example 15-1 was formed as in the which 0.9 mol/kg of LIPF, 0.05 mol/kg of the compound case of Example 14-1, except that an electrolytic solution in represented by Chemical Formula 8(6) and 0.05 mol/kg of the which 0.9 mol/kg of LIPF and 0.1 mol/kg of LiBF as elec compound represented by Chemical Formula 13(2) as elec trolyte salts were dissolved was used. 45 trolyte salts were dissolved was used. Moreover, as Comparative Example 15-1, a secondary bat Example 15-2 tery was formed as in the case of Example 15-2, except that the oxide-containing film was not arranged. A secondary battery of Example 15-2 was formed as in the The cycle characteristics of the secondary batteries of case of Example 14-1, except that an electrolytic solution in 50 Examples 15-1 to 15-5 and Comparative Example 15-1 were which 0.9 mol/kg of LIPF and 0.1 mol/kg of the compound determined as in the case of Examples 14-1 to 14-11. The represented by Chemical Formula 8(6) as electrolyte salts results are shown in Table 15 together with the results of were dissolved was used. Example 14-1 and Comparative Example 14-1. TABLE 1.5 Battery shape: laminate type Anode active material: silicon (electron beam evaporation) Method of forming coating film: Sol-gel method

DISCHARGE CAPACITY RETENTION COATING RATIO FILM ELECTROLYTE SALT (%)

EXAMPLE 14-1 PRESENT LiPF 42 1.0 mol/kg US 8,932,761 B2 53 54 TABLE 15-continued Battery shape: laminate type Anode active material: silicon (electron beam evaporation) Method of forming coating film: Sol-gel method

DISCHARGE CAPACITY RETENTION COATING RATIO FILM ELECTROLYTE SALT (%) EXAMPLE 15-1 PRESENT LiPF LiBF 43 0.9 mol/kg 0.1 mol/kg EXAMPLE 1.5-2 PRESENT CHEMICAL FORMULA 8(6) 46 0.1 mol/kg EXAMPLE 15-3 PRESENT CHEMICAL FORMULA 9(2) 48 0.1 mol/kg EXAMPLE 15-4 PRESENT CHEMICAL FORMULA 13(2) 43 0.1 mollkg EXAMPLE 15-S PRESENT LiPF CHEMICAL CHEMICAL 48 0.8 mol/kg FORMULA 8(6) FORMULA 13(2) 0.05 mol/kg 0.05 mol/kg COMPARATIVE ABSENT LiPF 23 EXAMPLE 14-1 1.0 mol/kg COMPARATIVE ABSENT LiPF CHEMICAL FORMULA 8(6) 32 EXAMPLE 1.5-1 0.9 mol/kg 0.1 mol/kg

As shown in Table 15, it was found out by comparison 25 In the above-described examples, the case where a cyclic between Example 14-1 and Examples 15-1 to 15-5 that when carbonate is used as a solvent is described; however, the same LiBF, the compound represented by Chemical Formula 8(6), tendency is confirmed even in the case where a chain carbon the compound represented by Chemical Formula 9(2), the ate represented by Chemical Formula 1 which includes a compound represented by Chemical Formula 13(2) or the like halogen is used. was included as the electrolyte salt in addition to LiPF, 30 higher cycle characteristics could be obtained. Moreover, it The invention claimed is: was confirmed by comparison between Example 15-2 and 1. An anode used in a battery including a cathode, an anode Comparative Example 15-1 that even in the case where and an electrolyte, the anode comprising: another electrolyte salt was added to LiPF, an effect of 35 an anode current collector, and improving the cycle characteristics by arranging the coating an anode active material layer on the anode current collec film could be obtained. tor, wherein, Although the present invention is described referring to the the anode active material layer includes a plurality of embodiments and the examples, the invention is not limited to anode active material particles each anode active them, and can be variously modified. For example, in the 40 material particle including at least one of silicon and above-described embodiments and the above-described tin, examples, the case where the electrolytic solution or the gel an oxide-containing film being formed by a liquid-phase electrolyte in which a polymer compound holds the electro deposition method, a sol-gel method, a coating lytic solution is used as an electrolyte is described; however, method or a dip coating method on at least a region of any other electrolyte may be used. Examples of the electro 45 each anode active material particle being in contact lyte include an ionic conducting inorganic compound Such as ionic conducting ceramic, ionic conducting glass or ionic with the electrolyte at its surface and an interior sur crystal, any other inorganic compound, and a mixture of the face of each anode active material particle, inorganic compounds and the electrolytic solution or the gel the oxide-containing film includes (a) an oxide of at least electrolyte. 50 one of silicon, germanium, and tin, and (b) at least one Moreover, in the above-described embodiment and the of a fluorine anion, a tetrafluorobarate ion and a Sul above-described examples, the battery using lithium as an fate ion. electrode reactant is described; however, the invention is 2. The anode according to claim 1, wherein the thickness of applicable to batteries using any other alkali metal Such as the oxide-containing film is within a range from 0.1 nm to 500 Sodium (Na) or potassium (K), an alkali earth metal Such as 55 nm both inclusive. magnesium (Mg) or calcium (Ca) or any other light metal 3. The anode according to claim 1, wherein the anode Such as aluminum. active material layer includes a metal including a metal ele Further, in the above-described embodiment and the ment which is not alloyed with an electrode reactant in gaps above-described examples, the cylindrical type secondary between the anode active material particles adjacent to each battery, the laminate film type secondary battery and the coin 60 other. type secondary battery are described in detail; however, the 4. The anode according to claim 3, wherein gaps between invention is applicable to a secondary battery with any other the anode active material particles are filled with the metal. shape Such as a button type or a prismatic type, or a secondary 5. The anode according to claim 3, wherein the metal battery with any other configuration such as a laminate con element includes at least one kind selected from the group figuration in the same manner. Further, the invention is appli 65 consisting of iron, cobalt, nickel, Zinc and copper. cable to not only the secondary batteries but also other bat 6. The anode according to claim 1 wherein the oxide is teries such as primary batteries. alloyed with an electrode reactant. US 8,932,761 B2 55 7. An anode used in a battery including a cathode, an anode and an electrolyte, the anode comprising: an anode current collector, and an anode active material layer on the anode current collec tor, wherein, 5 the anode active material layer includes a plurality of anode active material particles, each anode active material particle including at least one of silicon and tin, an oxide-containing film on at least a region of each 10 anode active material particle being in contact with the electrolyte surface at its surface and an interior Surface of each anode active material particle, the oxide containing film including an oxide of at least one of silicon, germanium and tin, and 15 the oxide-containing film is deposited by immersing the anode current collector on which the anode active material layer is formed in a solution formed by dis Solving (a) at least one of boric acid and aluminum chloride as an anion trapping agent in (b) at least one 20 of hexafluorosilicic acid, hexafluorostannic acid and hexafluorogermanic acid. 8. The anode according to claim 7 wherein the oxide is alloyed with an electrode reactant. k k k k k 25