Search

CN-122000463-A - Nonaqueous electrolyte and lithium ion battery containing same

CN122000463ACN 122000463 ACN122000463 ACN 122000463ACN-122000463-A

Abstract

The invention relates to a non-aqueous electrolyte and a lithium ion battery containing the same. In order to solve the problem that the existing lithium ion battery is difficult to consider high temperature, low temperature, multiplying power and safety performance, the invention provides a non-aqueous electrolyte which comprises lithium salt, an additive and an organic solvent, wherein the additive comprises a compound with a specific structure, the compound can form a stable protective film on a negative electrode and form a protective film on a positive electrode through oxidization, a silicon oxygen structure of the compound can inhibit LiPF 6 from hydrolysis and remove corrosive HF, and the damage of acidic substances to CEI and SEI is reduced, so that the high-temperature storage and circulation performance of the lithium ion battery is improved, and the low-temperature multiplying power discharge and overcharge safety performance of the battery are improved.

Inventors

  • CHEN LI
  • WANG TINGTING
  • LI XIAOBO
  • GAN CHAOLUN

Assignees

  • 张家港市国泰华荣化工新材料有限公司

Dates

Publication Date
20260508
Application Date
20241105

Claims (10)

  1. 1. A non-aqueous electrolyte comprising an organic solvent, a lithium salt and an additive, wherein the additive comprises one or more of the compounds of formula a and formula B, formula a being as follows: m, n are independently 1, 2, 3, 4, 5 or 6, R 1 、R 2 are each independently H or And at least one is R 3 、R 4 、R 5 is each independently alkyl of 1 to 6 carbon atoms; Formula B is as follows: f. q is independently 1, 2,3, 4, 5 or 6, R 6 is alkyl of 1 to 6 carbon atoms or alkenyl of 2 to 6 carbon atoms, R 7 、R 8 is each independently H or And at least one is R 3 、R 4 、R 5 is each independently an alkyl group of 1 to 6 carbon atoms.
  2. 2. The nonaqueous electrolyte according to claim 1, wherein in formula a, R 3 、R 4 、R 5 is a methane group, respectively; and/or, in formula a, m, n are independently 1, 2 or 3; And/or, in the formula B, R 6 is methyl, ethyl, propyl or propenyl, and R 3 、R 4 、R 5 is methane respectively; And/or, in formula B, f, q are independently 1, 2 or 3; And/or, in formula B, R 7 、R 8 is respectively
  3. 3. The nonaqueous electrolyte according to claim 1, wherein the compound represented by formula a comprises: The compounds of formula B include:
  4. 4. the nonaqueous electrolyte according to claim 1, wherein the additive accounts for 0.05% -5% of the total mass of the nonaqueous electrolyte.
  5. 5. The nonaqueous electrolyte according to claim 1, wherein the organic solvent comprises one or more of a substituted or unsubstituted carbonate, a substituted or unsubstituted carboxylate, a substituted or unsubstituted ether, a substituted or unsubstituted sulfone, a substituted or unsubstituted sulfoxide, and a substituted or unsubstituted benzene; And/or the organic solvent accounts for 60% -90% of the total weight of the electrolyte.
  6. 6. The nonaqueous electrolytic solution according to claim 5, wherein the organic solvent comprises an alkyl carbonate and an alkylene carbonate, and the mass ratio of the alkyl carbonate to the alkylene carbonate is 1 (2 to 3).
  7. 7. The nonaqueous electrolyte according to claim 1, wherein the lithium salt comprises one or more of lithium hexafluorophosphate, lithium bistrifluoromethylsulfonyl imide, lithium bistrifluorosulfonate, lithium tetrafluoroborate, lithium dioxalate borate, lithium oxalyldifluoroborate, lithium difluorooxalate phosphate, lithium tetrafluorooxalate phosphate, lithium fluorosulfonate, and lithium 4, 5-dicyano-2-trifluoromethylimidazole; and/or the lithium salt accounts for 8% -30% of the total weight of the electrolyte.
  8. 8. The nonaqueous electrolyte according to claim 1, further comprising other additives selected from one or more of a cyclic carbonate having a double bond, a cyclic carbonate having a halogen, a sultone, a sulfonate, a sulfate, a sulfite, a benzene compound, a fluorobenzene compound, a nitrile compound, a boron compound, a phosphorus compound, an amine compound, a silicon-containing compound, and a heterocyclic compound, wherein the other additives account for 0.3 to 10% of the total weight of the electrolyte.
  9. 9. The non-aqueous electrolyte of claim 8, wherein the other additives include at least vinyl sulfate.
  10. 10. A lithium ion battery comprising a positive electrode, a negative electrode, and an electrolyte, characterized in that the electrolyte is the nonaqueous electrolyte according to any one of claims 1 to 9.

Description

Nonaqueous electrolyte and lithium ion battery containing same Technical Field The invention relates to the technical field of lithium ion batteries, in particular to a nonaqueous electrolyte and a lithium ion battery containing the same. Background Lithium Ion Batteries (LIBs) are increasingly used in different fields such as electric automobiles, renewable energy storage, national defense, aerospace and the like. However, existing lithium ion batteries have significantly reduced performance under high and low temperature conditions, which is closely related to the properties of the positive electrode-electrolyte interface (CEI) and the negative electrode-electrolyte interface (SEI). The presence of the CEI and SEI layers is critical to the stability and structural integrity of the battery, and thus for LIBs, the formation of good-performing CEI and SEI by regulation of the electrolyte formulation is critical. Therefore, further researches on the electrolyte are needed to develop more electrolytes which can effectively improve the high-temperature storage and cycle performance of the lithium ion battery and simultaneously give consideration to the low-temperature rate discharge performance and the overcharge safety performance. Disclosure of Invention The invention aims to provide a nonaqueous electrolyte capable of improving high-temperature storage, cycle performance, low-temperature rate discharge and overcharge safety performance of a lithium ion battery. Another object of the present invention is to provide a lithium ion battery having excellent overall performance, which contains the above nonaqueous electrolytic solution. In order to achieve the above purpose, the invention adopts the following technical scheme: The invention provides a nonaqueous electrolyte, which comprises an organic solvent, lithium salt and an additive, wherein the additive comprises one or more of compounds shown in a formula A and a formula B, and the formula A is as follows: m, n are independently 1, 2, 3, 4, 5 or 6, R 1、R2 are each independently H or And at least one isR 3、R4、R5 is each independently alkyl of 1 to 6 carbon atoms; Formula B is as follows: f. q is independently 1, 2,3, 4, 5 or 6, R 6 is alkyl of 1 to 6 carbon atoms or alkenyl of 2 to 6 carbon atoms, R 7、R8 is each independently H or And at least one isR 3、R4、R5 is each independently an alkyl group of 1 to 6 carbon atoms. Further, in formula a, R 3、R4、R5 is each a methane group. Further, in formula a, m, n are independently 1, 2 or 3. Further, in formula B, R 6 is methyl, ethyl, propyl or propenyl, and R 3、R4、R5 are each methane. Further, in formula B, f, q are independently 1, 2 or 3. Further, in formula B, R 7、R8 is each In an embodiment of the present invention, the compound of formula a includes: The compounds of formula B include: Further, the additive accounts for 0.05% -5% of the total mass of the nonaqueous electrolyte. Still further, the additive accounts for 0.1% -2% of the total mass of the nonaqueous electrolyte. Further, the additive accounts for 0.3% -1% of the total mass of the nonaqueous electrolyte. Further, the organic solvent includes one or more of a substituted or unsubstituted carbonate, a substituted or unsubstituted carboxylate, a substituted or unsubstituted ether, a substituted or unsubstituted sulfone, a substituted or unsubstituted sulfoxide, and a substituted or unsubstituted benzene. Still further, the organic solvent is two or more of fluoroethylene carbonate, difluoroethylene carbonate, fluoroethylsulfone, dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, methylethyl carbonate, ethylene glycol dimethyl ether, r-butyrolactone, methyl acetate, ethyl acetate, difluoroethyl acetate, propyl acetate, butyl acetate, methyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, sulfolane, 1, 2-tetrafluoroethyl-2, 3-tetrafluoropropyl ether, methylethylsulfone, dimethylsulfoxide, fluorobenzene, and methyltrifluoroethyl carbonate. In the embodiment of the invention, the organic solvent comprises alkyl carbonate and ethylene carbonate, and the mass ratio of the alkyl carbonate to the ethylene carbonate is 1 (2-3). According to some specific embodiments of the invention, the organic solvent comprises (1-3): 2-5): 1 (4-8) by mass of ethylene carbonate, diethyl carbonate, propylene carbonate and methyl ethyl carbonate. Further, the organic solvent accounts for 60% -90% of the total weight of the electrolyte. Still further, the organic solvent accounts for 70% -85% of the total weight of the electrolyte. Further, the organic solvent accounts for 80% -85% of the total weight of the electrolyte. Further, the lithium salt includes one or more of lithium hexafluorophosphate, lithium bis (trifluoromethylsulfonyl) imide, lithium bis (fluorosulfonyl) imide, lithium tetrafluoroborate, lithium dioxaborate, lithium oxalato difluoroborate, lithium difluorooxalato phosphate, lithium tetrafluorooxalat