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CN-115706262-B - Electrolyte additive, electrolyte containing electrolyte additive, lithium ion secondary battery and application of electrolyte additive

CN115706262BCN 115706262 BCN115706262 BCN 115706262BCN-115706262-B

Abstract

The invention provides an electrolyte additive, an electrolyte containing the electrolyte additive, a lithium ion secondary battery and application thereof. The electrolyte additive comprises a substance represented by the following formula (1), wherein R 1 is a substituted or unsubstituted C 1‑6 alkyl group, and R 2 is selected from the group consisting of a substituted or unsubstituted C 1‑6 aliphatic hydrocarbon group, a 6-10 membered substituted or unsubstituted carbocyclic or heterocyclic aromatic group, wherein the heterocyclic aromatic group comprises 1 to 3 heteroatoms selected from N, S, O or any combination thereof.

Inventors

  • Zhong haoyue
  • CHEN YINGTAO
  • ZHU CHENG
  • XUE MANLI
  • YANG FAN

Assignees

  • 株式会社村田制作所

Dates

Publication Date
20260508
Application Date
20210805

Claims (11)

  1. 1. An electrolyte additive for a lithium ion secondary battery, characterized by comprising a substance represented by the following formula (1): (1) Wherein the method comprises the steps of R 1 is substituted or unsubstituted C 1-6 alkyl, and R 2 is selected from the group consisting of a substituted or unsubstituted C 1-6 alkylene group, a 6-10 membered substituted or unsubstituted carbocyclic or heterocyclic aromatic group, wherein the heterocyclic aromatic group contains 1 to 3 heteroatoms selected from N, S, O or any combination thereof.
  2. 2. The electrolyte additive of claim 1 wherein R 1 is a halogen substituted C 1-3 alkyl or C 1-3 alkyl.
  3. 3. The electrolyte additive of claim 1 wherein R 2 is selected from the group consisting of C 1-6 alkylene, halogen or C 1-3 alkyl substituted C 1-6 alkylene, phenylene, halogen or C 1-3 alkyl substituted phenylene, benzothiazolylene, and halogen or C 1-3 alkyl substituted benzothiazolylene.
  4. 4. The electrolyte additive according to claim 1, wherein the substance represented by formula (1) is any one of the following: 、 And 。
  5. 5. An electrolyte comprising an organic solvent, a lithium salt, and the electrolyte additive of any one of claims 1 to 4.
  6. 6. The electrolyte according to claim 5, wherein the amount of the electrolyte additive is in the range of 0.1 to 1 part by weight based on 100 parts by weight of the total weight of the organic solvent and the lithium salt.
  7. 7. The electrolyte of claim 6, wherein the amount of the electrolyte additive ranges from 0.1 to 0.5 parts by weight based on 100 parts by weight of the total weight of the organic solvent and the lithium salt.
  8. 8. The electrolyte of claim 5, wherein the lithium salt is selected from the group consisting of LiPF 6 、LiBF 4 、LiAsF 6 、LiCF 3 SO 3 、LiN(SO 2 F) 2 、LiN(SO 2 CF 3 ) 2 、LiC(SO 2 CF 3 ) 3 、Li 2 SiF 6 、 or any combination of the above.
  9. 9. The electrolyte of claim 5 wherein the organic solvent is selected from the group consisting of propylene carbonate, butylene carbonate, fluoroethylene carbonate, diethyl carbonate, dipropyl carbonate, methylethyl carbonate, ethylene carbonate, dimethyl carbonate, or any combination thereof.
  10. 10. A lithium ion secondary battery, characterized by comprising: The positive electrode plate is provided with a plurality of grooves, A negative electrode sheet, A diaphragm, and The electrolyte of any one of claims 5 to 9.
  11. 11. Use of the electrolyte additive according to any one of claims 1 to 4 for preparing an electrolyte for a lithium ion secondary battery or a lithium ion secondary battery.

Description

Electrolyte additive, electrolyte containing electrolyte additive, lithium ion secondary battery and application of electrolyte additive Technical Field The invention relates to the field of lithium ion secondary batteries, in particular to an electrolyte additive, an electrolyte containing the electrolyte additive, a lithium ion secondary battery and application of the electrolyte additive. Background With the rapid development of economy and society, more urgent demands are also put on lithium ion batteries with high energy density and long cycle life. High nickel/silicon carbon type lithium ion batteries are considered as viable solutions to the current problem. However, the high nickel type positive electrode and the silicon carbon type negative electrode have insufficient structural stability in an electric cycle, and thus may cause serious deterioration of the battery under high temperature, high rate conditions. During charge and discharge of a lithium ion battery, a solvent may be decomposed and the decomposed substance will form a positive electrode electrolyte interface film (CEI film) on the positive electrode surface of the battery and a solid electrolyte interface film (SEI film) on the negative electrode surface. The CEI film and the SEI film can effectively inhibit the solvent from further reacting with the electrode. However, during the electric cycle, the structure of the high nickel positive electrode is unstable, and the CEI film is easily broken, thereby causing elution of transition metal ions. In addition, the silicon anode material is easy to expand in volume in the charge and discharge process, so that an SEI film is broken, an electrode structure is collapsed, and the battery performance is greatly reduced. At present, a method for improving battery performance is generally used in which a plurality of film-forming additives are added to an electrolyte solution so that stable protective interfaces (CEI film and SEI film) are formed on the surfaces of a positive electrode and a negative electrode, respectively. In the prior art, such film forming additives include phosphate esters, nitriles, sulfonate compounds. During the first charge-discharge cycle, the film-forming additive undergoes a decomposition reaction in preference to the solvent, and its decomposition product forms a stable dense CEI film on the positive electrode surface. In addition, in order to protect the negative electrode, it is necessary to add a film-forming additive such as borate, nitrogen-containing lithium salt, carbonate, etc., so that a stable negative electrode SEI film is formed on the surface of the negative electrode during the first charge-discharge cycle. However, in order to protect both the positive and negative electrodes, it is necessary to use various additives in combination at the same time, which brings more impurities, causes side reactions, and increases uncontrollability of the reaction process. The reduction of the types of additives as much as possible and the control of the amount of additives are key points for improving the battery performance. Therefore, in order to solve the aforementioned problems, there is still a need to develop an electrolyte additive capable of effectively forming an SEI film and a CEI film and ensuring electrical properties of a lithium ion secondary battery. Disclosure of Invention The invention mainly aims to provide an electrolyte additive, an electrolyte containing the electrolyte additive, a lithium ion secondary battery and application thereof, so as to solve the problems that more impurities are brought in, side reactions are caused and uncontrollability of a reaction process is increased when a plurality of electrolyte additives are used in combination in the prior art. In order to achieve the above object, according to one aspect of the present invention, there is provided an electrolyte additive comprising a substance represented by the following formula (1): Wherein R 1 is a substituted or unsubstituted C 1-6 alkyl group and R 2 is selected from the group consisting of a substituted or unsubstituted C 1-6 aliphatic alkylene group, a 6-10 membered substituted or unsubstituted carbocyclic or heterocyclic aromatic group, wherein the heterocyclic aromatic group comprises 1 to 3 heteroatoms selected from N, S, O or any combination thereof. Further, in the above electrolyte additive, R 1 is a halogen-substituted C 1-3 alkyl group or C 1-3 alkyl group. Further, in the above electrolyte additive, R 2 is selected from the group consisting of C 1-6 alkylene, halogen or C 1-3 alkyl substituted C 1-6 alkylene, phenylene, halogen or C 1-3 alkyl substituted phenylene, benzothiazolylene, and halogen or C 1-3 alkyl substituted benzothiazolylene. Further, in the above electrolyte additive, the substance represented by formula (1) is any one of the following: According to another aspect of the present invention, there is provided an electrolyte comprising an organic so