US 20110281 177A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2011/0281177 A1 Xu (43) Pub. Date: Nov. 17, 2011 (54) NONAQUEOUSELECTROLYTESOLVENTS (52) U.S. Cl. .......... 429/330; 429/336: 429/338; 429/340 AND ADDITIVES (75) Inventor: Kang Conrad Xu, North Potomac, (57) ABSTRACT MD (US) A series of polar and aprotic organic molecules, which, when used as solvents or additives in nonaqueous electrolytes, (73) Assignee: s SENSE Rented afford improved performance for electrochemical cells that Adelphi, MD (US) operate at high Voltages. These polar and aprotic solvents or s additives may contain at least one unsaturated functionality (21) Appl. No.: 12/987,241 per molecule. The unsaturated functionality is conjugated with the polar functionality of the molecule. The unsaturated (22) Filed: Jan. 10, 2011 functionality that is either a double or triple bond could be between carbon-carbon, or between carbon-heteroatom, or Related U.S. Application Data between hetroatom-heteroatom. Nonaqueous electrolyte Solutions are provided comprising one or more lithium salts (60) Provisional application No. 61/334.265, filed on May dissolved in the mixture solvents, which comprises, in all 13, 2010. possible ratios, at least one of the polar, aprotic and unsatur O O ated solvent or additives, one or more cyclic carbonic diesters Publication Classification Such as ethylene carbonate, and one or more acyclic carbonic (51) Int. Cl. diesters such as dimethyl carbonate, diethyl carbonate, and HIM IO/02 (2006.01) ethylmethyl carbonate. Patent Application Publication Nov. 17, 2011 Sheet 1 of 6 US 2011/0281177 A1 2 -Fs.N N O i. O S \s - N. O c5 - S 9 :-o- so - - -A-N uS 1 -/-O lO re- *- Patent Application Publication Nov. 17, 2011 Sheet 2 of 6 US 2011/0281177 A1 z O ty - E y 2 s o Y 'i, z S - N 1 NN als.E3 n SE. N. - l Y ne ! e e 2 Cf.S. .n g. .3: 1 g as were O y Z Y - Y | Patent Application Publication Nov. 17, 2011 Sheet 3 of 6 US 2011/0281177 A1 */ Y gs | SlE l / h 2 O a O| Yo? g || g L- O Patent Application Publication Nov. 17, 2011 Sheet 4 of 6 US 2011/0281177 A1 F s" E. - u C D N s 2 c5 O e ". E L 5. 9 s i s zuo IWu/ Patent Application Publication Nov. 17, 2011 Sheets of 6 US 2011/0281177 A1 }IeS (W)uopeanuosuojo Patent Application Publication Nov. 17, 2011 Sheet 6 of 6 US 2011/0281177 A1 s s d ad s g e 9 L US 2011/0281 177 A1 Nov. 17, 2011 NONAQUEOUSELECTROLYTE SOLVENTS potentials become focus of research efforts, and the passiva AND ADDITIVES tion layer formed by these solvents or additives of the con ventional solutions can no longer ensure the stable operation CROSS REFERENCE TO RELATED of the cell chemistry. APPLICATION 0001. This application claims the benefit of U.S. Provi SUMMARY sional Patent Application No. 61/334.265 filed on May 13, 2010, the complete disclosure of which, in its entirety, is 0009. In view of the foregoing, an embodiment herein herein incorporated by reference. provides an electrochemical device comprising a negative GOVERNMENT INTEREST electrode of a metal and an electrode active material that reversibly intercalates and de-intercalates cations; a positive 0002 The invention was made in a U.S. Army laboratory electrode comprising an electrode active material that revers and so the embodiments described herein may be manufac tured, used, sold, imported and/or licensed by or for the ibly intercalates and de-intercalates any of cations and United States Government without the payment of royalties anions; a barrier comprising any of a porous polyolefin sepa thereon. rator and a gellable polymer film separating the negative electrode from the positive electrode; and a nonaqueous elec BACKGROUND trolyte contacting the negative electrode and the positive elec trode, the nonaqueous electrolyte comprising at least one 0003 1. Technical Field 0004. The embodiments herein generally relate to non unsaturated molecule acting as a solvent or an additive and aqueous electrolytes that Support the operation of electro comprising any of the following structures (1) through (8): chemical devices with high cell Voltages, and more particu larly, to the solvents and additives that form the nonaqueous electrolytes and can stably support the cell chemistry of the (1) electrochemical devices with high cell Voltages. 0005 2. Description of the Related Art C X C 0006. The electrochemical devices that output high cell R1 NO O m\R2 voltages utilize nonaqueous and aprotic solvents to dissolve rt) the conducting salts, because these solvents are able to afford (2) the stability against the oxidative or reductive reactions H H incurred by electrode surfaces of extreme potentials. Because (e }-or-to-(-)-pi the electrolyte components are almost never thermodynami (O), cally stable on the strongly reductive surfaces of anode or strongly oxidative Surfaces of cathode, the electrochemical (CH2) stability is rather attained through the passivation of the elec trode surfaces. The above passivation is realized by the initial decompositions of solvents in trace amount and the concomi (3) H tant deposition of these decomposition products which deac R2 C R4 tivate the catalytic sites of the electrode surfaces. Generally, all electrochemical devices that produce cell Voltages higher than 3.0 V, and particularly in lithium-based battery chemis tries, certain solvents were developed in the conventional R Z R3 Solutions so that their decomposition products on anode and (4) cathode Surfaces are able to form dense and protective passi H vation layers. These solvents include ethylene carbonate R2 C R4 (EC), vinylene carbonate (VC), and other polar and aprotic Solvents and/or additives, and have become indispensable " components in commercial Li ion batteries. In other words, R Z R3 the conventional Liion batteries operate at high Voltages (3-5 (5) V), which were made possible by the passivation film formed R-Z-R2 on the surfaces of the anode and/or cathode. While providing protection, the film also presents resistance to the kinetics of (6) the cell chemistry, rendering poor power density as well as H poor low temperature performances. N =c-(-)- 0007. However, the passivation layers formed by the 2 (7) above-described solvents and/or additives in conventional R electrolytes also constitute the most resistive component in the electrochemical cells, which not only compromises the cell performances at low temperatures but also impose the R3-N=C ) kinetic restrictions on the power density of the devices at room temperature. } :)iii. 0008 Furthermore, as the battery chemistries of higher R1 energy density are being pursued, cathode materials of higher US 2011/0281 177 A1 Nov. 17, 2011 approximately 10% to 100% with respect to a total solvent -continued weight, wherein a concentration of the additive ranges from (8) approximately 0.005% to 10% with respect to the total sol vent weight, and wherein a concentration of the lithium salt CCEO A ranges from approximately 0.5 to 3.0 mole/liter. R2 0013 The active material of the negative electrode may comprise any of lithium metal, lithium alloys with other met wherein i, j, and k are integers independent from each other als, carbonaceous materials with various degrees of graphiti and range from 0 to 1, andl, m, and nare integers independent Zation, lithiated metal oxides, and chalcogenides. Also, the from each other and range from 0 to 2, respectively, wherein active material of the positive electrode may comprise any of R" are saturated substituents comprising hydrogen, C1-C10 transition metal oxides, metalphosphates, chalcogenides, and normal or C3-C10 branched alkyls, halogen radicals, carbonaceous materials with various degree of graphitization. alkoxyls, thioalkoxyls, aromatic radicals, and unsaturated Substituents comprising any of the radicals in the following 0014) Another embodiment provides an electrolyte solu structures (9) through (11): tion and a method of forming the same comprising at least one lithium salt and a solvent system mixed with at least one lithium salt, the solvent system of a plurality of polar and (9) aprotic organic molecules comprising at least one unsaturated \ /R5 functionality per molecule that is conjugated with a polar CFC functionality of the molecule, wherein at least one unsatur A. V R4 R6 ated functionality comprises any of a double bond and a triple (10) bond between any of a carbon-carbon chain, a carbon-het -CEC-R eroatom chain, and a hetroatom-heteroatom chain; at least (11) one cyclic carbonic diester; and at least one acyclic carbonic \ /R5 diester. Preferably, the solvent system comprises any of the CECEC A V structures (1) through (8): R4 R6 (0010 wherein Rare selected from any of H radical, (1) C1-C10 normal or C3-C10 branched alkyls, halogen radicals, alkoxyls, thioalkoxyls, and aromatic radicals. C X C 0011. The nonaqueous electrolyte may comprise at least R1 NO rto)O m\R2 one of the R' substituents selected from the structures (9) through (11). Additionally, the nonaqueous electrolyte may (2) comprise one of the structures (1), (2), (3), (4), (5), (6), or (7). H H and wherein at least one of l, m, and n equals Zero. Further R ( }-or-to-(-)-pi more, the nonaqueous electrolyte may comprise only struc (O), ture (1), wherein X comprises sulfonyl, and wherein one of i or equals Zero. Moreover, the nonaqueous electrolyte may (CH2) comprise one of the structures (1) or (2), wherein X comprises Sulfonyl, carbonyl, thionyl orphosphoryl, whereini, j, k, l, m, (3) and n equal zero, and wherein at least one of R' is selected H from radicals comprising any of structures (9) through (11).