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CN-122000460-A - Lithium ion battery electrolyte and lithium ion battery

CN122000460ACN 122000460 ACN122000460 ACN 122000460ACN-122000460-A

Abstract

The application relates to a lithium ion battery electrolyte and a lithium ion battery. The electrolyte comprises a first additive and a second additive, wherein the first additive comprises a lithium sulfonate compound, the mass percentage of the first additive in the electrolyte is A% which is more than or equal to 0.1 and less than or equal to 4, the second additive comprises a boron-nitrile compound, the mass percentage of the second additive in the electrolyte is B% which is more than or equal to 0.2 and less than or equal to 2, the battery satisfies that A/B is more than or equal to 0.1 and less than or equal to 10, and (A+B)/X is more than or equal to 0.01 and less than or equal to 0.1, wherein X is the single-sided density of a negative electrode active material layer in a negative electrode, and the unit is g/m 2 , and X is more than or equal to 30 and less than or equal to 80. According to the scheme provided by the application, a compact and thinner organic-inorganic composite SEI film can be formed on the anode interface through the synergistic effect of the first additive and the second additive, so that the stability of the anode interface is effectively enhanced, and the comprehensive requirements of the high-low temperature cycle performance and the safety performance of the lithium ion battery under high voltage are comprehensively met.

Inventors

  • ZHANG GUILIN
  • Duan Kaijia
  • YU LIJUAN
  • HU DALIN
  • LIAO XINGQUN

Assignees

  • 深圳市豪鹏科技股份有限公司

Dates

Publication Date
20260508
Application Date
20260302

Claims (10)

  1. 1. The lithium ion battery electrolyte is characterized by comprising a first additive and a second additive, wherein the first additive comprises a lithium sulfonate compound, the mass percentage of the first additive in the electrolyte is A% which is more than or equal to 0.1 and less than or equal to 4, the second additive comprises a boron-nitrile compound, the mass percentage of the second additive in the electrolyte is B% which is more than or equal to 0.2 and less than or equal to 2, and the battery meets the following requirements: 0.1≤A/B≤10; 0.01≤(A+B)/X≤0.1; Wherein X is the single-sided density of the anode active material layer in the anode, and the unit is g/m 2 , and X is more than or equal to 30 and less than or equal to 80.
  2. 2. The lithium ion battery electrolyte of claim 1, wherein (a+b)/X is 0.015-0.08.
  3. 3. The lithium ion battery electrolyte of claim 1, wherein 0.5 +.a/B +.8.
  4. 4. The lithium ion battery electrolyte according to claim 1, wherein A is 0.5≤A≤4, and/or B is 0.2≤B≤1.
  5. 5. The lithium ion battery electrolyte according to claim 1, wherein the lithium sulfonate compound has the following structural formula: wherein R1 is selected from one of fluorine atom, fluorocarbon alkyl, amino and fluorine amino.
  6. 6. The lithium ion battery electrolyte according to claim 5, wherein the lithium sulfonate compound is selected from at least one of the following compounds: Compound 1 Compound 2 Compound 3 Compound 4 Compound 5 Compound 6 Compound 7 Compound 8.
  7. 7. The lithium ion battery electrolyte according to claim 1, wherein the boron-nitrile compound has the following structural formula: Wherein m, n 1 and n 2 are natural numbers greater than or equal to 0, when m=0, R2 and R3 are each independently selected from-CH 3, -F, fluoroalkyl, nitrile and fluorine-containing nitrile, R7-R9 are each independently selected from-CH 3, -C=O, -O-, fluoroalkyl, nitrile and fluorine-containing nitrile, and at least one side chain of R2, R3, R7-R9 contains a nitrile group, and when m >0, R2-R9 are each independently selected from-CH 3, -C=O, -O-, fluoroalkyl, nitrile and fluorine-containing nitrile, and at least one side chain of R2-R9 contains a nitrile group.
  8. 8. The lithium ion battery electrolyte according to claim 7, wherein the boron-nitrile containing compound is selected from at least one of the following compounds: Compound a Compound b Compound c Compound d Compound e Compound f Compound g Compound h A compound i.
  9. 9. A lithium ion battery comprising a negative electrode, a positive electrode, and an electrolyte, wherein the electrolyte is the electrolyte according to any one of claims 1 to 8.
  10. 10. The lithium ion battery of claim 9, wherein the negative electrode comprises a negative electrode current collector, and a negative electrode active material layer coated on at least one side of the negative electrode current collector, the negative electrode active material layer comprising a negative electrode active material comprising at least one of natural graphite, artificial graphite, mesophase micro carbon spheres, hard carbon, soft carbon, silicon, a silicon-carbon composite, a Li-Sn alloy, a Li-Sn-O alloy, sn, snO, snO 2 , lithiated TiO 2 -Li 4 Ti 5 O 12 of spinel structure, and a Li-Al alloy.

Description

Lithium ion battery electrolyte and lithium ion battery Technical Field The application relates to the technical field of batteries, in particular to lithium ion battery electrolyte and a lithium ion battery. Background Lithium ion batteries have become a core power source for portable electronic devices and new energy automobiles because of their advantages of high energy density, low self-discharge rate, long cycle life, and the like. Its proper operation depends on the synergy between the positive electrode, the negative electrode, the electrolyte and the separator. During charge and discharge, a solid electrolyte interface film (SEI film) is formed on the surface of the negative electrode, and has a decisive influence on battery performance. However, the conventional SEI film has loose structure and poor stability, is easy to crack and reconstruct in the circulation process, not only causes continuous interface side reaction and electrolyte decomposition, but also can cause co-intercalation of solvent molecules into a graphite negative electrode to damage an electrode structure, thereby limiting the cycle life and safety of the battery under severe working conditions such as high voltage, high temperature, low temperature and the like. Disclosure of Invention In order to solve or partially solve the problems in the related art, the application provides the lithium ion battery electrolyte and the lithium ion battery, which can form a compact and thinner organic-inorganic composite SEI film on the interface of the negative electrode through the synergistic effect of the first additive and the second additive, effectively enhance the stability of the interface of the negative electrode and comprehensively meet the comprehensive requirements of the high-low temperature cycle performance and the safety performance of the lithium ion battery under high voltage. The first aspect of the application provides lithium ion battery electrolyte, which comprises a first additive and a second additive, wherein the first additive comprises a lithium sulfonate compound, the mass percentage of the first additive in the electrolyte is A percent, A is more than or equal to 0.1 and less than or equal to 4, the second additive comprises a boron-nitrile compound, the mass percentage of the second additive in the electrolyte is B percent, B is more than or equal to 0.2 and less than or equal to 2, and the battery meets the following conditions: 0.1≤A/B≤10; 0.01≤(A+B)/X≤0.1; Wherein X is the single-sided density of the anode active material layer in the anode, and the unit is g/m 2, and X is more than or equal to 30 and less than or equal to 80. In some embodiments of the invention, 0.015≤A+B)/X≤0.08. In some embodiments of the invention, 0.5≤A/B≤8. In some embodiments of the invention, 0.5≤A≤4, and/or 0.2≤B≤1. In some embodiments of the invention, the lithium sulfonate compound has the following structural formula: wherein R1 is selected from one of fluorine atom, fluorocarbon alkyl, amino and fluorine amino. In some embodiments of the invention, the lithium sulfonate compound is selected from at least one of the following compounds: Compound 1 Compound 2 Compound 3 Compound 4 Compound 5 Compound 6 Compound 7 Compound 8. In some embodiments of the invention, the boron-nitrile containing compound has the structural formula: Wherein m, n 1 and n 2 are natural numbers equal to or greater than 0. R2 to R9 are independently selected from-CH 3, -F, -C=O, -O-, fluoroalkyl, nitrile-containing alkyl and fluorine-containing nitrile-containing alkyl, and at least one side chain of R2 to R9 contains nitrile group. In some embodiments of the invention, the boron-nitrile containing compound is selected from at least one of the following compounds: Compound a Compound b Compound c Compound d Compound e Compound f Compound g Compound h A compound i. The second aspect of the application provides a lithium ion battery, which comprises a negative electrode, a positive electrode and electrolyte, wherein the electrolyte is the electrolyte. In some embodiments of the present invention, the anode includes an anode current collector, and an anode active material layer coated on at least one side of the anode current collector, the anode active material layer including an anode active material including at least one of natural graphite, artificial graphite, mesophase micro carbon spheres, hard carbon, soft carbon, silicon, a silicon-carbon composite, a Li-Sn alloy, a Li-Sn-O alloy, sn, snO, snO 2, a spinel structured lithiated TiO 2-Li4Ti5O12, a Li-Al alloy. The technical scheme provided by the application can comprise the following beneficial results: The application realizes the multidimensional accurate regulation and control of the cathode interface chemistry by limiting the specific numerical ranges of A (0.1% -4%), B (0.2% -2%), X (30 g/m 2~80g/m2) and introducing two key ratio constraints of 0.01-0.1 and 0.1-10, so that the two additives exert s