Additives for electrolytes in lithium-ion batteries

Abstract

To provide a method of improving the performance and safety of a lithium-ion battery.SOLUTION: The method includes using a nitrile-based low-molecular-weight organic compound of the general formula I, V or IX in the figure for the electrolyte.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates generally to additives for lithium ion batteries, and more particularly to nitrile-based additives for use with lithium ion battery electrolytes. [Background technology]

[0002] Lithium-ion batteries are widely used as energy sources, and their demand is increasing. Typically, such batteries include a negative electrode or anode, a positive electrode or cathode, and an electrolyte provided between the two spaced apart electrodes. The electrolyte may include organic molecules or polymers and generally also includes a lithium salt such as LiPF6, LiTFSI, or LiFSI. Additionally, the electrolyte may include linear carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC), or ethyl methyl carbonate (EMC), or cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC), or butylene carbonate (BC).

[0003] Various studies related to the properties and composition of electrolytes and aimed at improving the performance and safety of lithium-ion batteries have been reported in the art. For example, the use of additives containing one or more nitrile groups has been reported [Non-Patent Documents 1-3]. In fact, it is known in the art that organic compounds containing nitrile groups exhibit good electrochemical properties and stability at high voltages and temperatures.

[0004] There remains a need for methods to improve the performance and safety of lithium-ion batteries, particularly nitrile-based organic compounds for use as additives in electrolytes. Summary of the Invention [Means for solving the problem]

[0005] The present inventors have designed and prepared an additive for use with the electrolyte of a lithium-ion battery. The additive of the present invention is an organic compound described below, which contains at least one nitrile group. The organic compound is compatible with the electrolyte as well as other components of the battery.

[0006] The present invention therefore provides the following in accordance with its aspects: (1) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with the battery electrolyte, the compound having the following general formula I: [ka] During the ceremony: Q is a 5- to 12-membered ring or bicyclic ring, optionally containing one or more heteroatoms, the same or different, selected from the group consisting of N, O, and S; preferably, Q is a 5- to 10-membered ring, or a 5-membered ring, or a 6-membered ring, or a bicyclic ring; L is a linker, present or absent, comprising one or more of alkyl, alkene, and alkyne groups; A method in which m is an integer from 1 to 10, 1 to 6, 1 to 5, 1 to 4, or 1 to 3. (2) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with the battery electrolyte, the compound having the following general formula II: [ka] During the ceremony: X is C or N; L is a linker, present or absent, comprising one or more of an alkyl, alkene, and alkyne group; Each Ri is independently selected from the group consisting of H, alkyl, cycloalkyl, alkene, alkyne, aryl and alkylaryl, alkoxy, thioalkoxy, OH, SH, NH, halogen, halogenoalkyl, halogenoalkoxy, halogenothioalkoxy, cyanoalkyl, cyanoalkene, cyanoalkyne, CN, NO, SO, COOH, and acyloxycarbonyl; preferably selected from the group consisting of H, alkyloxy, halogen, halogenoalkyl, nitro, and cyano; more preferably selected from the group consisting of H, halogen, nitro, and cyano; m is an integer from 1 to 5, or from 1 to 4, or from 1 to 3; The method wherein m' is an integer from 0 to 5, 0 to 4, 0 to 3, 1 to 5, 1 to 4, or 1 to 3. (3) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with the battery electrolyte, the compound having the following general formula III: [ka] During the ceremony: X is C or N; Each Ri is independently selected from the group consisting of H, alkyl, cycloalkyl, alkene, alkyne, aryl and alkylaryl, alkoxy, thioalkoxy, OH, SH, NH, halogen atoms, halogenoalkyl, halogenoalkoxy, halogenothioalkoxy, cyanoalkyl, cyanoalkene, cyanoalkyne, CN, NO, SO, COOH, and acyloxycarbonyl; preferably, each Ri is independently selected from the group consisting of H, alkyloxy, halogen, halogenoalkyl, nitro, and cyano; more preferably, selected from the group consisting of H, halogen, nitro, and cyano; The method wherein m' is an integer from 0 to 5, 0 to 4, 0 to 3, 1 to 5, 1 to 4, or 1 to 3. (4) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with the battery electrolyte, the compound having the following general formula IV: [ka] During the ceremony: X is C or N; Each Ri is independently selected from the group consisting of H, alkyl, cycloalkyl, alkene, alkyne, aryl and alkylaryl, alkoxy, thioalkoxy, OH, SH, NH, halogen, halogenoalkyl, halogenoalkoxy, halogenothioalkoxy, cyanoalkyl, cyanoalkene, cyanoalkyne, CN, NO, SO, COOH, and acyloxycarbonyl; preferably selected from the group consisting of H, alkyloxy, halogen, halogenoalkyl, nitro, and cyano; more preferably selected from the group consisting of H, halogen, nitro, and cyano; The method wherein m' is an integer from 0 to 5, 0 to 4, 0 to 3, 1 to 5, 1 to 4, or 1 to 3. (5) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with the battery electrolyte, the compound having the following general formula A: [ka] wherein R1 to R5 are each independently selected from the group consisting of H, alkyl, cycloalkyl, alkene, alkyne, aryl and alkylaryl, alkoxy, thioalkoxy, OH, SH, NH2, halogen atom, halogenoalkyl, halogenoalkoxy, halogenothioalkoxy, cyanoalkyl, cyanoalkene, cyanoalkyne, CN, NO2, SO2, COOH, and acyloxycarbonyl; preferably, R1 to R5 are each independently selected from the group consisting of H, alkyloxy, halogen, halogenoalkyl, nitro, and cyano; more preferably, selected from the group consisting of H, halogen, nitro, and cyano. (6) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with the battery electrolyte, the compound having the following general formula B: [ka] During the ceremony: X is C and R3 is H; or X is N; R1 to R5 are each independently selected from the group consisting of H, alkyl, cycloalkyl, alkene, alkyne, aryl and alkylaryl, alkoxy, thioalkoxy, OH, SH, NH2, halogen atoms, halogenoalkyl, halogenoalkoxy, halogenothioalkoxy, cyanoalkyl, cyanoalkene, cyanoalkyne, CN, NO2, SO2, COOH, and acyloxycarbonyl; preferably, R1 to R5 are each independently selected from the group consisting of H, alkyloxy, halogen, halogenoalkyl, nitro, and cyano; more preferably, selected from the group consisting of H, halogen, nitro, and cyano. (7) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with a battery electrolyte, wherein the compound is A1, A2, A3, or A4 below: [ka] [ka] [ka] [ka] (8) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with a battery electrolyte, wherein the compound is B1, B2, B3, B4, B5, B6, B7, or B8 below. [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] (9) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with the battery electrolyte, the compound having the following general formula V: [ka] During the ceremony: L is a linker, present or absent, comprising one or more of an alkyl, alkene, and alkyne group; A method in which R1 to R3 are each independently an alkyl group; preferably a C1 to C6 or C1 to C3 alkyl group; more preferably at least one of R1 to R3 is CH3, or each of R1 to R3 is CH3. (10) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with the battery electrolyte, the compound having the following general formula VI: [ka] During the ceremony: n is an integer from 0 to 6, or from 0 to 5, or from 0 to 4, or from 0 to 3, or from 0 to 2; preferably, n is an integer from 0 to 3; more preferably, n is 0 or 1; A method in which R1 to R3 are each independently an alkyl group; preferably a C1 to C6 or C1 to C3 alkyl group; more preferably at least one of R1 to R3 is CH3, or each of R1 to R3 is CH3. (11) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with the battery electrolyte, the compound having the following general formula C: [ka] wherein n is an integer from 0 to 6, or from 0 to 5, or from 0 to 4, or from 0 to 3, or from 0 to 2; preferably, n is an integer from 0 to 3; more preferably, n is How to be 0 or 1. (12) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile organic compound in combination with a battery electrolyte, wherein the compound is C1 or C2 below: [ka] [ka] (13) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with the battery electrolyte, the compound having the following general formula IX: [ka] During the ceremony: R1 is CN or CH3; L1 and L2 are each independently present or absent and each independently a linker comprising an alkyl, alkene, and / or alkyne group; The method wherein Y is Na, K, or Li; preferably, Y is Na. (14) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with the battery electrolyte, the compound having the following general formula X: [ka] During the ceremony: L1 and L2 are each independently a linker that is present or absent and each independently includes one or more of an alkyl, alkene, and / or alkyne group; The method wherein Y is Na, K, or Li; preferably, Y is Na. (15) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with the battery electrolyte, the compound having the following general formula XI: [ka] During the ceremony: n1 and n2 are each independently 0 to 10, 0 to 6, or 0 to 3. are integers; preferably, at least one of n1 and n2 is 0, or both n1 and n2 are 0; The method wherein Y is Na, K, or Li; preferably, Y is Na. (16) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with the battery electrolyte, the compound having the following general formula D: [ka] wherein Y is Na, K or Li; preferably Y is Na. (17) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with a battery electrolyte, wherein the compound has the following general formula D1: [ka] (18) A compound having the following general formula VII: [ka] wherein R1 and R2 are each independently selected from the group consisting of H, alkyl, cycloalkyl, alkene, alkyne, aryl and alkylaryl, alkoxy, thioalkoxy, OH, SH, NH2, halogen atoms, halogenoalkyl, halogenoalkoxy, halogenothioalkoxy, cyanoalkyl, cyanoalkene, cyanoalkyne, CN, NO2, SO2, COOH, and acyloxycarbonyl; preferably selected from the group consisting of H, alkyloxy, halogen, halogenoalkyl, nitro, and cyano; more preferably selected from the group consisting of H, halogen, nitro, and cyano. (19) A compound having the following general formula VIII: [ka] A compound of the formula: wherein X is a halogen atom; preferably X is F. (20) A compound of the following formula B4 [ka] (21) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with a battery electrolyte, wherein the compound is defined in any one of (18) to (20) above. (22) The method of any one of (1) to (17), and (21), wherein the nitrile-based organic compound is added to an electrolyte; optionally, the amount of the additive (nitrile-based organic compound) is about 0.01 to about 5.0% by weight, or about 0.01 to about 5.0% by weight, or about 0.01 to about 3.0% by weight, or about 0.01 to about 1.0% by weight, or about 0.05 to about 1.0% by weight, or about 0.1 to about 1.0% by weight, or about 0.1 to about 0.8% by weight, or about 0.1 to about 0.5% by weight, or about 0.1 to about 0.3% by weight, or about 0.1% by weight, or about 0.5% by weight. (23) An electrolyte comprising a compound selected from the group consisting of I, II, III, IV, A, B, A1, A2, A3, A4, B1, B2, B3, B4, B5, B6, B7, B8, V, VI, C, C1, C2, IX, X, XI, D, and D1, as defined in any one of the methods (1) to (17) above. (24) An electrolyte comprising a compound defined in any one of (18) to (20) above. (25) A battery comprising an electrolyte defined in (23) or (24) above. (26) An additive for an electrolyte used in a lithium ion battery, comprising a compound selected from the group consisting of I, II, III, IV, A, B, A1, A2, A3, A4, B1, B2, B3, B4, B5, B6, B7, B8, V, VI, C, C1, C2, IX, X, XI, D, and D1, as defined in any one of the methods (1) to (17) above. (27) An additive for an electrolyte used in a lithium-ion battery, comprising a compound defined in any one of (18) to (20) above. (28) The lithium ion battery is a battery in which the cathode contains a lithium-containing material. The method, electrolyte, battery, or additive according to any one of (1) to (27). (29) The method, electrolyte, battery, or additive according to any one of (1) to (27) above, wherein the lithium-ion battery is a battery whose cathode comprises lithium cobalt oxide (LCO), lithium manganese oxide (LMO), lithium nickel oxide (LNO), and the like, including olivine, lithium oxide, and nickel manganese cobalt oxide (NMC). (30) The method, electrolyte, battery, or additive according to (28) or (30) above, which improves battery performance (capacity, reversibility).

[0007] Other objects, advantages and features of the present invention will become more apparent upon understanding the following non-restrictive description of specific embodiments thereof, given by way of example only with reference to the accompanying drawings.

[0008] The patent or application file contains one or more drawings executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[0009] In the accompanying drawing: [Brief explanation of the drawings]

[0010] [Figure 1] Cycle data of LMFP-LTO battery (PC / EMC / DMC (4 / 3 / 3) + 1M LiPF6 according to the invention + 0.1 wt% additive (compounds of series A)) vs. reference after 300 cycles at 45°C. [Figure 2] Capacitance (0.05C) of LMFP-LTO battery (PC / EMC / DMC (4 / 3 / 3) + 1M LiPF6 + 0.1% by weight of additive according to the invention (compound of series A)) at 45°C vs. reference. [Figure 3] Nyquist plot of LMFP-LTO battery (PC / EMC / DMC (4 / 3 / 3) + 1 M LiPF6 + 0.1 wt% of additive according to the invention (compound of series A)) vs. reference at 0 and 100 cycles. [Figure 4] Cycle data of LMFP-LTO battery (PC / EMC / DMC (4 / 3 / 3) + 1M LiPF6 according to the invention + 0.5 wt% additive (compounds of series B)) vs. reference after 300 cycles at 45°C. [Figure 5] Capacitance (0.05C) of LMFP-LTO battery (PC / EMC / DMC (4 / 3 / 3) + 1M LiPF6 + 0.5% by weight of additive according to the invention (compound of series B)) at 45°C vs. reference. [Figure 6] Nyquist plot of LMFP-LTO battery (PC / EMC / DMC (4 / 3 / 3) + 1 M LiPF6 + 0.5 wt. % additive according to the invention (compound of series B)) vs. reference at 0 and 200 cycles. [Figure 7]Cycle data of LMFP-LTO battery (PC / EMC / DMC (4 / 3 / 3) + 1M LiPF6 according to the invention + 0.5 wt% additive (series C compound)) vs. reference after 300 cycles at 45°C. [Figure 8] Capacitance (0.05C) of LMFP-LTO battery (PC / EMC / DMC (4 / 3 / 3) + 1M LiPF6 + 0.5% by weight of additive according to the invention (compound of series C)) at 45°C versus reference. [Figure 9] Nyquist plot of LMFP-LTO battery (PC / EMC / DMC (4 / 3 / 3) + 1 M LiPF6 + 0.5 wt. % additive according to the invention (compound of series C)) vs. reference at 0 and 100 cycles. [Figure 10] Cycle data of LMFP-LTO battery (PC / EMC / DMC (4 / 3 / 3) + 1M LiPF6 according to the invention + 0.5 wt% additive (compound of series D)) vs. reference after 100 cycles at 45°C.

[0011] [Figure 11] Capacitance (0.05C) of LMFP-LTO battery (PC / EMC / DMC (4 / 3 / 3) + 1M LiPF6 + 0.5% by weight of additive according to the invention (compound of series D)) at 45°C vs. reference. DETAILED DESCRIPTION OF THE INVENTION

[0012] Before further describing the present invention, it is to be understood that the present invention is not limited to the specific embodiments described below, as variations of such embodiments may be made and still fall within the scope of the appended claims. It is also to be understood that the terminology employed is for the purpose of describing particular embodiments and is not intended to be limiting. Instead, the scope of the present invention will be determined by the appended claims.

[0013] In order to provide a clear and consistent understanding of the terms used herein, the following definitions are provided. Moreover, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0014] The use of the words "a" or "an" when used in conjunction with the word "comprising" in the claims and / or specification may mean "one," but is consistent with the meanings of "one or more," "at least one," and "one or more than one." Similarly, the word "another" may mean "at least a second or more."

[0015] As used in this specification and the claims, the words "comprising" (and all forms of compris- ing, such as "comprise" and "composites"), "having" (and all forms of having, such as "have" and "has"), "including" (and all forms of including, such as "include" and "includes"), or "containing" (and all forms of containing, such as "contain" and "contains") are inclusive or open-ended terms and do not exclude additional, unrecited elements or process steps.

[0016] As used herein when referring to a numerical value or percentage, the term "about" includes the variability, statistical deviation, and human error resulting from the method employed to determine the numerical value or percentage. Further, each numerical parameter in this application should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0017] The terms "alkyl" or "alk," as used herein, unless otherwise specified, refer to a monovalent group derived from a straight or branched chain saturated hydrocarbon of from 1 to 15 carbon atoms, examples of which include methyl, ethyl, n- and iso-propyl, n-, sec-, iso- and tert-butyl, neopentyl, and the like, and which may be optionally substituted with one, two, three, or, in the case of alkyl groups of two or more carbon atoms, four substituents.

[0018] The terms "alkoxy" or "alkyloxy," as used interchangeably herein, refer to an alkyl group attached to the parent molecular group through an oxygen atom.

[0019] The terms "alkylthio" or "thioalkoxy," as used interchangeably herein, refer to an alkyl group attached to the parent molecular group through a sulfur atom.

[0020] The term "alkylene," as used herein, refers to a saturated divalent hydrocarbon group derived from a straight or branched chain saturated hydrocarbon by removing two hydrogen atoms, examples of which are methylene, ethylene, isopropylene, and the like.

[0021] The term "alkenyl," as used herein, unless otherwise specified, refers to a monovalent straight or branched chain group of 2 to 15 carbon atoms, e.g., 2 to 6 carbon atoms, or 2 to 4 carbon atoms, containing one or more carbon-carbon double bonds, examples of which are ethenyl, 1-propenyl, 2-propenyl, 2-methyl-1-propenyl, 1-butenyl, 2-butenyl, and the like, which may be optionally substituted with 1, 2, 3, or 4 substituents.

[0022] The term "alkynyl," as used herein, refers to a monovalent straight or branched chain radical of 2 to 6 carbon atoms containing a carbon-carbon triple bond, exemplified by ethynyl, 1-propynyl, and the like, which may be optionally substituted with 1, 2, 3, or 4 substituents.

[0023] The term "cycloalkyl," as used herein, unless otherwise specified, refers to a monovalent saturated or unsaturated non-aromatic cyclic hydrocarbon radical of 3 to 8 carbon atoms, examples of which include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, bicyclo[2.2.1]heptyl, and the like.

[0024] The terms "halogen" or "halo", as used interchangeably herein, refer to F, Cl, Br, and I.

[0025] As used herein, the term "heteroatom" is understood to be oxygen, sulfur, or nitrogen.

[0026] The present inventors have designed and prepared an additive for use with the electrolyte of a lithium-ion battery. The additive of the present invention is an organic compound described below, which contains at least one nitrile group. Furthermore, the organic compound is compatible with the electrolyte as well as other components of the battery.

[0027] More specifically, the additives of the present invention used in conjunction with the electrolyte are nitrile-based organic compounds having the general formulas I-XI, A, B, C, and D described herein and illustrated below. [ka] [ka] [ka] [ka] [ka]

[0028] Examples of such organic compounds are those defined in Table 1 below, namely, compounds A1 to A4, B1 to B8, C1 to C2, and D1. Table 1. Organic compounds according to the invention (series A, B, C, D)

[0029] [Table 1-1] [Table 1-2] [ka] [ka]

[0030] The present invention is described in further detail by the following non-limiting examples. Nitrile organic compounds used as additives in lithium-ion electrolytes

[0031] Example 1 - General procedure for preparing compounds. To a solution of aldehyde (1 eq.) in 15 mL of chloroform, molonodinitrile (1.5 eq.) and a few drops of triethylamine are added. The mixture is refluxed overnight under nitrogen. After returning to room temperature, dichloromethane is added, and the solution is washed twice with water and dried over MgSO4. After removing the solvent, the residue is chromatographed (silica gel / dichloromethane) to give a solid.

[0032] Example 2 - Compound B1 [ka]

[0033] Bright yellow solid (70%). NMR 1 H (400 MHz,CDCl3) δ: 7.69 (d,1H,J = 4Hz); 7.64 (s,1H); 7.38 (dd,1H,J = 4Hz,J = 12Hz); 6.95 (d,1H,J = 12Hz); 3.99 (s,3H); 3.93 (s,3H).

[0034] Example 3-Compound B2

change

[0035] Yellow solid (40%). NMR 1 H (400 MHz, CDCl3) δ: 7.77 (s,1H).NMR 19 F (400 MHz, CDCl3) δ: -132.55 (s,2H); -143.68 (s,1H); -158.50 (s,1H).

[0036] Example 4-Compound B3

change

[0037] White solid. NMR 1 H (400 MHz, CDCl3) δ: 8.60 (d,1H,J = 4Hz); 8.25 (dd,1H,J = 4Hz,J = 12Hz); 8.18 (s,1H); 8.15 (d,1H,J = 12Hz).

[0038] Example 5-Compound B4

change

[0039] Fresh yellow solid. NMR 1 H (400 MHz, CDCl3) δ: 8.12 (d,1H,J = 4Hz); 8.03 (s,1H); 7.67 (dd,1H,J = 4Hz,J = 12Hz).NMR 19 F (400 MHz, CDCl3) δ: -63.65 (s, 3F).

[0040] Example 6-Compound B5

change

[0041] White solid. NMR 1 H (400 MHz, CDCl3) δ: 8.02 (d,2H,J = 12Hz); 7.83 (d,2H,J = 8Hz); 7.80 (s,1H).NMR 19 F (400 MHz, CDCl3) δ: -63.48 (s, 3F).

[0042] Example 7-Compound B6

change

[0043] White solid. NMR 1 H (400 MHz, CDCl3) δ: 7.99 (d,2H,J = 8Hz); 7.83 (d,2H,J = 8Hz); 7.74 (s,1H).

[0044] Example 8-Compound B7

change

[0045] Light orange solid. NMR 1 H (400 MHz, CDCl3) δ: 8.39 (d,2H,J = 12Hz); 8.07 (d,2H,J = 8Hz); 7.88 (s,1H).

[0046] Example 9 - Compound B8 [ka]

[0047] Pink solid. NMR 1 H (400 MHz,CDCl3) δ: 8.89 (d,2H,J = 12Hz); 7.81 (s,2H); 7.68 (d,2H,J = 8Hz).

[0048] Compounds in series A and C, as well as compound D1, were commercially available and used as received.

[0049] Referring to the figures, Figures 1-3 summarize the results obtained using compounds of Series A; Figures 4-6 summarize the results obtained using compounds of Series B; Figures 7-9 summarize the results obtained using compounds of Series C; and Figures 10-11 summarize the results obtained using compounds of Series D. It is important to note that neither the inventive battery nor the reference battery contains vinylene carbonate (VC), which explains the poor stability after 300 cycles. Nevertheless, as can be seen, the battery containing the additive of the present invention exhibits much better stability.

[0050] As can be seen from Figure 2, the use of 0.1 wt% of compound A1 or A4 allows for better reversibility along with improved battery capacity. Furthermore, an overall decrease in battery resistance is observed (Figure 3).

[0051] Figure 5 shows the results obtained for compounds B1 and B4. The use of 0.5 wt% additive allows for an improvement in the battery capacity. An overall decrease in the battery resistance is observed (Figure 6).

[0052] Figure 7 shows the results obtained for compounds C1 and C2. The use of 0.5 wt% additive provides good stability after 300 cycles at 45°C. As can be seen, better results are obtained for compound C1 (short carbon chain).

[0053] The results obtained for compound D1 are shown in Figure 10. As can be seen from Figure 11, the use of 0.5 wt% of compound D1 allows for better reversibility along with improved battery capacity.

[0054] As will be appreciated by those skilled in the art, the additive used in conjunction with the electrolyte will be adapted to be compatible with the components of the battery, including the electrolyte and the cathode active material.

[0055] The present invention is described in the context of a lithium manganese iron phosphate (LMFP)-lithium titanium oxide (LTO) battery. As will be understood by those skilled in the art, other lithium-ion batteries may also be used. In other words, any battery in which the cathode active material comprises a lithium-containing material may be used. Such lithium-containing materials may include olivine, lithium oxide, nickel manganese cobalt oxide (NMC), lithium cobalt oxide (LCO), lithium manganese oxide (LMO), lithium nickel oxide (LNO), and the like.

[0056] Additionally, as will be appreciated by those skilled in the art, the anode material can be of any suitable type, such as, for example, lithium alloys, Si, SiOx, mixtures of graphite and carbon, titanates, lithium titanate, and the like.

[0057] The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be accorded the broadest interpretation consistent with the description as a whole.

[0058] This specification references several documents, the contents of which are incorporated herein by reference in their entireties. References

[0059] 1.Rohan R.et al.J.Phys.Chem.C(2016),120(12),6450-6458. 2.Kim Y.-S.et al.ACS Appl.Mater.Interfaces(2014),6(11),8913-8920. 3.Pohl B.et al.J.Electrochem.Soc.(2015),162(3),A460-A464.

[0060] According to a preferred embodiment of the present invention, for example, the following is provided: (Section 1) 1. A method for improving the performance and safety of a lithium-ion battery comprising using a nitrile-based organic compound in combination with the battery's electrolyte, said compound having the following general formula I: [ka] During the ceremony: Q is a 5- to 12-membered ring or bicyclic ring, optionally containing one or more heteroatoms, the same or different, selected from the group consisting of N, O, and S; preferably, Q is a 5- to 10-membered ring, or a 5-membered ring, or a 6-membered ring, or a bicyclic ring; L is a linker, present or absent, comprising one or more of alkyl, alkene, and alkyne groups; A method in which m is an integer from 1 to 10, 1 to 6, 1 to 5, 1 to 4, or 1 to 3. (Section 2) 1. A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with the battery's electrolyte, the compound having the following general formula II: [ka] During the ceremony: X is C or N; L is, present or absent, a linker comprising one or more of alkyl, alkene, and alkyne groups; each Ri is independently selected from the group consisting of H, alkyl, cycloalkyl, alkene, alkyne, aryl and alkylaryl, alkoxy, thioalkoxy, OH, SH, NH, halogen atoms, halogenoalkyl, halogenoalkoxy, halogenothioalkoxy, cyanoalkyl, cyanoalkene, cyanoalkyne, CN, NO, SO, COOH, and acyloxycarbonyl; preferably selected from the group consisting of H, alkyloxy, halogen, halogenoalkyl, nitro, and cyano; more preferably selected from the group consisting of H, halogen, nitro, and cyano; m is an integer from 1 to 5, or from 1 to 4, or from 1 to 3; The method wherein m' is an integer from 0 to 5, 0 to 4, 0 to 3, 1 to 5, 1 to 4, or 1 to 3. (Section 3) 1. A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with the battery's electrolyte, the compound having the following general formula III: [ka] During the ceremony: X is C or N; each Ri is independently selected from the group consisting of H, alkyl, cycloalkyl, alkene, alkyne, aryl and alkylaryl, alkoxy, thioalkoxy, OH, SH, NH, halogen atoms, halogenoalkyl, halogenoalkoxy, halogenothioalkoxy, cyanoalkyl, cyanoalkene, cyanoalkyne, CN, NO, SO, COOH, and acyloxycarbonyl; preferably, each Ri is independently selected from the group consisting of H, alkyloxy, halogen, halogenoalkyl, nitro, and cyano; more preferably, H, halogen, nitro, and cyano. Selected from the group consisting of: The method wherein m' is an integer from 0 to 5, 0 to 4, 0 to 3, 1 to 5, 1 to 4, or 1 to 3. (Section 4) 1. A method for improving the performance and safety of a lithium-ion battery comprising using a nitrile-based organic compound in combination with the battery's electrolyte, the compound having the following general formula IV: [ka] During the ceremony: X is C or N; each Ri is independently selected from the group consisting of H, alkyl, cycloalkyl, alkene, alkyne, aryl and alkylaryl, alkoxy, thioalkoxy, OH, SH, NH, halogen, halogenoalkyl, halogenoalkoxy, halogenothioalkoxy, cyanoalkyl, cyanoalkene, cyanoalkyne, CN, NO, SO, COOH, and acyloxycarbonyl; preferably selected from the group consisting of H, alkyloxy, halogen, halogenoalkyl, nitro, and cyano; more preferably selected from the group consisting of H, halogen, nitro, and cyano; The method wherein m' is an integer from 0 to 5, 0 to 4, 0 to 3, 1 to 5, 1 to 4, or 1 to 3. (Section 5) 1. A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with the battery's electrolyte, the compound having the following general formula A: [ka] wherein R1 to R5 are each independently selected from the group consisting of H, alkyl, cycloalkyl, alkene, alkyne, aryl and alkylaryl, alkoxy, thioalkoxy, OH, SH, NH2, halogen atoms, halogenoalkyl, halogenoalkoxy, halogenothioalkoxy, cyanoalkyl, cyanoalkene, cyanoalkyne, CN, NO2, SO2, COOH, and acyloxycarbonyl; preferably, R1 to R5 are each independently selected from the group consisting of H, alkyloxy, halogen, halogenoalkyl, nitro, and cyano; more preferably, H, halogen, nitro, and cyano. A method selected from the group consisting of: (Section 6) 1. A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with the battery's electrolyte, the compound having the following general formula B: [ka] During the ceremony: X is C and R3 is H; or X is N; R1 to R5 are each independently selected from the group consisting of H, alkyl, cycloalkyl, alkene, alkyne, aryl and alkylaryl, alkoxy, thioalkoxy, OH, SH, NH2, halogen atoms, halogenoalkyl, halogenoalkoxy, halogenothioalkoxy, cyanoalkyl, cyanoalkene, cyanoalkyne, CN, NO2, SO2, COOH, and acyloxycarbonyl; preferably, R1 to R5 are each independently selected from the group consisting of H, alkyloxy, halogen, halogenoalkyl, nitro, and cyano; more preferably, selected from the group consisting of H, halogen, nitro, and cyano. (Section 7) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with a battery electrolyte, wherein the compound is A1, A2, A3, or A4 below. [ka] [ka] [ka] [ka] (Section 8) 1. A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with a battery electrolyte, wherein the compound is B1, B2, B3, B4, B5, B6, B7, or B8 below. [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] (Section 9) 1. A method for improving the performance and safety of a lithium-ion battery comprising using a nitrile-based organic compound in combination with the battery's electrolyte, the compound having the general formula V: [ka] During the ceremony: L is a linker, present or absent, comprising one or more of an alkyl group, an alkene group, and an alkyne group; A method in which R1 to R3 are each independently an alkyl group; preferably a C1 to C6 or C1 to C3 alkyl group; more preferably at least one of R1 to R3 is CH3, or each of R1 to R3 is CH3. (Section 10) 1. A method for improving the performance and safety of a lithium-ion battery comprising using a nitrile-based organic compound in combination with the battery's electrolyte, the compound having the following general formula VI: [ka] During the ceremony: n is an integer from 0 to 6, or from 0 to 5, or from 0 to 4, or from 0 to 3, or from 0 to 2; preferably, n is an integer from 0 to 3; more preferably, n is 0 or 1; A method in which R1 to R3 are each independently an alkyl group; preferably a C1 to C6 or C1 to C3 alkyl group; more preferably at least one of R1 to R3 is CH3, or each of R1 to R3 is CH3. (Section 11) 1. A method for improving the performance and safety of a lithium-ion battery comprising using a nitrile-based organic compound in combination with the battery's electrolyte, the compound having the following general formula C: [ka] wherein n is an integer from 0 to 6, or from 0 to 5, or from 0 to 4, or from 0 to 3, or from 0 to 2; preferably, n is an integer from 0 to 3; more preferably, n is 0 or 1. (Section 12) A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with a battery electrolyte, wherein the compound is C1 or C2 below: [ka] [ka] (Section 13) 1. A method for improving the performance and safety of a lithium-ion battery comprising using a nitrile-based organic compound in combination with the battery's electrolyte, the compound having the following general formula IX: [ka] During the ceremony: R1 is CN or CH3; L1 and L2 are each independently present or absent and each independently a linker comprising an alkyl, alkene, and / or alkyne group; Y is Na, K, or Li; preferably, Y is Na. (Section 14) 1. A method for improving the performance and safety of a lithium-ion battery comprising using a nitrile-based organic compound in combination with the battery's electrolyte, the compound having the general formula X: [ka] During the ceremony: L1 and L2 are each independently a linker that is present or absent and each independently includes one or more of an alkyl, alkene, and / or alkyne group; The method wherein Y is Na, K, or Li; preferably, Y is Na. (Section 15) 1. A method for improving the performance and safety of a lithium-ion battery comprising using a nitrile-based organic compound in combination with the battery's electrolyte, the compound having the following general formula XI: [ka] During the ceremony: n1 and n2 are each independently an integer from 0 to 10, or from 0 to 6, or from 0 to 3; preferably, at least one of n1 and n2 is 0, or both n1 and n2 are 0; The method wherein Y is Na, K, or Li; preferably, Y is Na. (Section 16) 1. A method for improving the performance and safety of a lithium-ion battery comprising using a nitrile-based organic compound in combination with the battery's electrolyte, said compound having the following general formula D: [ka] wherein Y is Na, K, or Li; preferably, Y is Na. (Section 17) Lithium-ion battery performance involving the use of nitrile-based organic compounds in conjunction with the battery electrolyte and a method for improving safety, wherein the compound has the following general formula D1: [ka] (Section 18) A compound having the general formula VII: [ka] wherein R1 and R2 are each independently selected from the group consisting of H, alkyl, cycloalkyl, alkene, alkyne, aryl and alkylaryl, alkoxy, thioalkoxy, OH, SH, NH2, halogen atoms, halogenoalkyl, halogenoalkoxy, halogenothioalkoxy, cyanoalkyl, cyanoalkene, cyanoalkyne, CN, NO2, SO2, COOH, and acyloxycarbonyl; preferably selected from the group consisting of H, alkyloxy, halogen, halogenoalkyl, nitro, and cyano; more preferably selected from the group consisting of H, halogen, nitro, and cyano. (Section 19) A compound having the following general formula VIII: [ka] A compound of the formula: wherein X is a halogen atom; preferably X is F. (Section 20) A compound of formula B4 below [ka] (Section 21) 21. A method for improving the performance and safety of a lithium-ion battery, comprising using a nitrile-based organic compound in combination with the battery's electrolyte, wherein the compound is defined in any one of paragraphs 18 to 20 above. (Section 22) 22. The method of any one of paragraphs 1 to 17 and 21, wherein the nitrile-based organic compound is added to an electrolyte; optionally, the amount of the additive (nitrile-based organic compound) is about 0.01 to about 5.0% by weight, or about 0.01 to about 5.0% by weight, or about 0.01 to about 3.0% by weight, or about 0.01 to about 1.0% by weight, or about 0.05 to about 1.0% by weight, or about 0.1 to about 1.0% by weight, or about 0.1 to about 0.8% by weight, or about 0.1 to about 0.5% by weight, or about 0.1 to about 0.3% by weight, or about 0.1% by weight, or about 0.5% by weight. (Section 23) 18. An electrolyte comprising a compound selected from the group consisting of I, II, III, IV, A, B, A1, A2, A3, A4, B1, B2, B3, B4, B5, B6, B7, B8, V, VI, C, C1, C2, IX, X, XI, D, and D1, as defined in the method according to any one of paragraphs 1 to 17 above. (Section 24) 21. An electrolyte comprising a compound as defined in any one of paragraphs 18 to 20 above. (Section 25) A battery containing an electrolyte as defined in paragraph 23 or 24 above. (Section 26) 18. An additive for an electrolyte used in a lithium ion battery, comprising a compound selected from the group consisting of I, II, III, IV, A, B, A1, A2, A3, A4, B1, B2, B3, B4, B5, B6, B7, B8, V, VI, C, C1, C2, IX, X, XI, D, and D1, as defined in the method according to any one of paragraphs 1 to 17 above. (Section 27) 21. An additive for an electrolyte used in a lithium-ion battery, comprising a compound as defined in any one of paragraphs 18 to 20 above. (Section 28) 28. The method, electrolyte, battery, or additive according to any one of items 1 to 27, wherein the lithium ion battery is a battery in which the cathode contains a lithium-containing material. (Section 29) Lithium-ion batteries are batteries whose cathodes include olivine, lithium oxide, nickel manganese cobalt oxide (NMC), lithium cobalt oxide (LCO), lithium manganese oxide (LMO), lithium nickel oxide (LNO), and the like. 28. The method, electrolyte, battery, or additive according to any one of items 1 to 27. (Section 30) 31. The method, electrolyte, battery or additive according to item 28 or 30, which improves battery performance (capacity, reversibility).

Claims

[Claim 1] The invention as described in the drawings.

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