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US-12620625-B2 - Electrolyte solution for lithium-ion battery and lithium-ion battery

US12620625B2US 12620625 B2US12620625 B2US 12620625B2US-12620625-B2

Abstract

The present disclosure relates to an electrolyte solution for a lithium-ion battery. The electrolyte solution includes an organic solvent, a lithium salt, and an additive. The electrolyte solution provided in the present disclosure includes a 6-membered heterocyclyl carboxylic anhydride additive, and can effectively inhibit gas production and the increase of interface impedance in the battery, improve the high-temperature stability of the battery, and prolong the service life of the battery.

Inventors

  • FEIYAN QIAO
  • Ping Lu
  • Haijun Wang
  • Rong HAO
  • Yi Pan

Assignees

  • BYD COMPANY LIMITED

Dates

Publication Date
20260505
Application Date
20221221
Priority Date
20200623

Claims (12)

  1. 1 . An electrolyte solution for a lithium-ion battery, wherein the electrolyte solution for a lithium-ion battery comprises an organic solvent, a lithium salt, and an additive; and the additive comprises a first additive represented by formula (1): wherein in the formula (1), X 1 , X 2 , X 3 and X 4 are each independently selected from CR or N, and at least one of X 1 , X 2 , X 3 or X 4 is N; and R in X 1 , X 2 , X 3 and X 4 are each independently selected from H, halogen, C 1 -C 4 alkyl, C 1 -C 4 substituted alkyl, C 4 -C 7 cycloalkyl, or C 1 -C 3 alkoxy, and wherein the additive further comprises a second additive, and the second additive comprises vinyl carbonate.
  2. 2 . The electrolyte solution according to claim 1 , wherein R in X 1 , X 2 , X 3 and X 4 is H.
  3. 3 . The electrolyte solution according to claim 1 , wherein any one or two of R in X 1 , X 2 , X 3 and X 4 is N.
  4. 4 . The electrolyte solution according to claim 1 , wherein based on the total weight of the electrolyte solution, a content of the organic solvent is 50%-90% by weight, a content of the lithium salt is 1%-20% by weight, and a content of the additive is 0.1%-10% by weight.
  5. 5 . The electrolyte solution according to claim 4 , wherein, based on the total weight of the electrolyte solution, the content of the organic solvent is 60%-85% by weight, the content of the lithium salt is 5%-15% by weight, and the content of the additive is 0.5%-8% by weight.
  6. 6 . The electrolyte solution according to claim 1 , wherein in the additive, based on the total weight of the additive, a content of the first additive is 30%-100% by weight.
  7. 7 . The electrolyte solution according to claim 6 , wherein in the additive, based on the total weight of the additive, the content of the first additive is 50%-100% by weight.
  8. 8 . The electrolyte solution according to claim 6 , wherein the second additive further comprises one or more of lithium boroxalate, or lithium difluorosulfonimide.
  9. 9 . The electrolyte solution according to claim 1 , wherein the first additive is 2,3-pyridine dicarboxylic anhydride, 3,4-pyridine dicarboxylic anhydride, 2,3-pyrazine dicarboxylic anhydride, or 4,5-pyridazine dicarboxylic anhydride.
  10. 10 . The electrolyte solution according to claim 1 , wherein the organic solvent is one or more of ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate, ethylene sulfite, propylene sulfite, diethyl sulfite, γ-butyrolactone, dimethyl sulfoxide, ethyl acetate, or methyl acetate.
  11. 11 . The electrolyte solution according to claim 1 , wherein the lithium salt is one or more of LiPF 6 , LiBF 4 , LiClO 4 , LiAsF 6 , Li CF 3 SO 3 , LiN(CF 3 SO 2 ) 2 , LiN(C 2 F 5 SO 2 ) 2 , LiC(CF 3 SO 2 ) 3 , or LiB(C 2 O 4 ) 2 .
  12. 12 . A lithium-ion battery, comprising the electrolyte solution according to claim 1 .

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation application of PCT application No. PCT/CN2021/101245 filed on Jun. 21, 2021, which claims priority to and benefits of Chinese Patent Application No. 202010584645.X, filed on Jun. 23, 2020. The entire content of all of the above-referenced applications is incorporated herein by reference. FIELD The present disclosure relates to the field of lithium-ion batteries, and specifically to an electrolyte solution for a lithium-ion battery and a lithium-ion battery. BACKGROUND Lithium-ion batteries with high energy density have always been an indispensable battery system in the battery market. However, during use of such a battery system, gases are produced by parasitic reactions between the interface and the electrolyte solution, and the interface impedance increase, resulting in the expansion of the battery and the shortened service life of the battery. In particular, in the pursuit of batteries with higher energy density in recent years, positive electrode materials suitable for high-voltage applications have been continuously developed, and the research of electrolyte solutions for the materials for high-voltage applications has also become the top priority. The limit voltage of existing electrolyte solution systems is 4.2 V, and a voltage of above 4.2 V causes the electrolyte solution to be oxidized at the positive electrode, which leads to gas production and unduly quick consumption of the electrolyte solution, resulting in safety hazards of the battery and shortening the service life of the battery. Therefore, the research of electrolyte solutions suitable for high-voltage systems is now an urgent priority. A conventional solution is to use a fluorine-containing solvent to increase the oxidative decomposition potential of the electrolyte solution. Although the oxidative decomposition potential of the fluorine-containing solvent is high, the release of HF at a later stage of the electrolyte solution will damage the particles of the positive and negative electrode materials and affect the service life of the battery. SUMMARY In order to further increase the oxidative decomposition potential of the electrolyte solution, solve the current problem of electrolyte solution decomposition under high voltage, and improve the high-voltage and high-temperature stability of the lithium-ion battery, the present disclosure provides an electrolyte solution for a lithium-ion battery and a lithium-ion battery. To achieve the above objectives, a first aspect of the present disclosure provides an electrolyte solution for a lithium-ion battery. The electrolyte solution for a lithium-ion battery includes an organic solvent, a lithium salt, and an additive. The additive includes a first additive represented by formula (1): where in the formula (1), X1, X2, X3 and X4 are each independently selected from CR or N, and at least one of X1, X2, X3 or X4 is N; and R in X1, X2, X3 and X4 are each independently selected from H, halogen, C1-C4 alkyl, C1-C4 substituted alkyl, C4-C7 cycloalkyl, or C1-C3 alkoxy. The inventors of the present disclosure have unexpectedly discovered that the additive represented by formula (1) can preferentially undergo oxidation reaction to form a film at a high-nickel positive electrode interface, and the resulting positive electrode film layer has good ion-conductivity and well prevents the interface deterioration reaction between the positive electrode that promotes oxidation reaction and the electrolyte solution during the cycle and storage processes, thereby preventing or reducing the increased polarization caused by the continuous increase of the film layer at the interface and the expansion caused by gases produced by the reactions at the interface. Thus, the present application is obtained. A second aspect of the present disclosure provides a lithium-ion battery. The lithium-ion battery includes the electrolyte solution for a lithium-ion battery provided in the first aspect of the present disclosure. Through the above technical solutions, the present disclosure provides an electrolyte solution for a lithium-ion battery and a lithium-ion battery, and the lithium-ion battery including the electrolyte solution provided in the present disclosure has better high-temperature stability and battery cycle performance at a high voltage. Other features and advantages of the present disclosure will be described in detail in the following detailed description. DETAILED DESCRIPTION Specific implementations of the present disclosure are described in detail below. It should be understood that the specific implementations described herein are merely used to describe and explain the present disclosure, but are not intended to limit the present disclosure. A first aspect of the present disclosure provides an electrolyte solution for a lithium-ion battery. The electrolyte solution for a lithium-ion battery includes an organic solvent, a lithium salt,