CN-119253068-B - Electrolyte and preparation method and application thereof

Abstract

The invention discloses an electrolyte, a preparation method and application thereof. The electrolyte comprises lithium salt, a gas production inhibiting additive, a solvent and a negative electrode film forming additive, wherein the gas production inhibiting additive comprises at least one of phenylvinyl sulfone and disilane compounds containing olefin groups. According to the electrolyte for reducing the gas production of the lithium ion battery, at least one of the disilane compound containing the olefin group and the phenyl vinyl sulfone is used as an additive to be added into the electrolyte, and the prepared electrolyte can effectively inhibit the gas production of the battery.

Inventors

• SHAO JUNHUA
• Tong Denghui
• PANG XINRU
• YAN ZHEN
• ZHANG XIAOXU
• ZHANG ZHIQIANG
• ZHANG LIJUAN
• LI HAIJIE
• YAN GUOFENG
• WANG YAZHOU
• YANG CUITING
• DENG XIAOMEI
• SHENG ZHIYUAN

Assignees

• 湖南法恩莱特新能源科技有限公司
• 河南省法恩莱特新能源科技有限公司
• 安徽法恩莱特新能源科技有限公司

Dates

Publication Date

20260505

Application Date

20240912

Claims (9)

1. 1. The electrolyte is characterized by comprising, by weight, 12.5-15 parts of lithium salt, 1-3 parts of a gas production inhibiting additive, 77-86 parts of a solvent and 0.5-5 parts of a negative electrode film forming additive; the gassing-suppressing additive consists of 1 part of phenylvinyl sulfone and 2 parts of divinyl tetramethyl disilane.
2. 2. An electrolyte according to claim 1, wherein the lithium salt comprises lithium hexafluorophosphate.
3. 3. An electrolyte as in claim 1, wherein the solvent comprises at least one of a cyclic carbonate and a linear carbonate.
4. 4. An electrolyte according to claim 3, wherein the cyclic carbonate comprises at least one of ethylene carbonate and propylene carbonate.
5. 5. An electrolyte as in claim 3, wherein said linear carbonate comprises at least one of dimethyl carbonate, ethylmethyl carbonate and diethyl carbonate.
6. 6. The electrolyte of claim 1 wherein the negative film-forming additive comprises at least one of fluoroethylene carbonate and vinylene carbonate.
7. 7. The electrolyte according to claim 1, wherein the concentration of the lithium salt is 1.0-1.5 mol/L.
8. 8. A method for preparing an electrolyte according to any one of claims 1 to 7, comprising the steps of: And dissolving lithium salt in an organic solvent to obtain a mixed solution, and adding a negative electrode film-forming additive and a gas production inhibiting additive into the mixed solution to obtain the electrolyte.
9. 9. A lithium ion battery comprising a positive electrode, a negative electrode, a separator and an electrolyte according to any one of claims 1 to 7.

Description

Electrolyte and preparation method and application thereof Technical Field The invention belongs to the technical field of ion batteries, and particularly relates to an electrolyte and a preparation method and application thereof. Background The rapid development of portable devices, electric vehicles and energy storage facilities has placed higher demands on the cost, charging rate, service life, safety, etc. of lithium ion batteries. However, lithium ion batteries can produce gas during cycling and storage, causing cell volume expansion, pole piece/separator misalignment, and increased cell polarization, which are important causes of battery life degradation and even safety concerns. Common additive for inhibiting gas production are nitriles, sulfonates, etc. Sulfonate esters such as PS can be reduced to form a chemically and electrochemically stable SEI film on the surface of the anode in preference to EC, and further decomposition of electrolyte components is effectively inhibited. The SEI component formed by the participation of the PS reduction product accelerates the lithium intercalation kinetics of Li + on the graphite surface to a certain extent, effectively inhibits high-temperature side reaction, reduces gas production, but leads to the increase of the internal resistance of the battery. PS is used as an additive in the electrolyte with optimal effect of inhibiting gas production of the battery, and is controlled due to carcinogenicity. It is therefore desirable to provide an electrolyte that reduces gassing in lithium ion batteries. Disclosure of Invention The present invention aims to solve at least one of the technical problems in the prior art described above. Therefore, the invention provides an electrolyte for reducing gas production of a lithium ion battery, which uses at least one of disilane compounds containing olefin groups and phenyl vinyl sulfones as an additive to be added into the electrolyte, and the prepared electrolyte can effectively inhibit gas production of the battery. The invention also provides a method for preparing the electrolyte. The invention also provides a lithium ion battery, which comprises a positive electrode, a negative electrode, a diaphragm and the electrolyte. According to one aspect of the present invention, an electrolyte is provided comprising a lithium salt, a gassing-suppressing additive, a solvent, and a negative film-forming additive; the gas production inhibiting additive comprises at least one of phenylvinyl sulfone and disilane compounds containing olefin groups shown in a formula I; Wherein R 1～R4 is independently selected from a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms having a hetero atom, or a hydrosilylation group having 1 to 10 silicon atoms having a substituent, R 1～R4 may be bonded to each other to form a ring, N and m may be the same or different and are independently 1 to 6. Embodiments according to the first aspect of the invention have at least the following advantageous effects: compared with the prior art, the invention can effectively inhibit the gas production of the battery after using the disilane additive containing the phenylvinyl sulfone and the alkylene, and does not influence the stability of the battery performance. The disilane containing the olefin group can participate in positive and negative electrode film forming to form a silane polymer with high lithium ion conductivity, and meanwhile, the olefin group silicon base can also remove active oxygen and trace water in the electrolyte, so that the gas production of the battery and the impedance increase in the high-temperature storage process can be obviously inhibited. The phenylvinyl sulfone has a wide electrochemical window, and its existence changes the reaction path of the electroreduction reaction and the subsequent oxidation reaction, which helps to build a stable SEI interface and reduce SEI dissolution and regenerated gas production. Both substances have no carcinogenicity and have high safety. In some embodiments of the invention, the electrolyte comprises the following components, by weight, 12.5-15 parts of lithium salt, 3 parts of a gassing inhibitor additive, 77-86 parts of a solvent and 5 parts of a negative electrode film forming additive; The additive for inhibiting gas production comprises 2 parts by weight of divinyl tetramethyl disilane and 1 part by weight of phenyl vinyl sulfone. In some embodiments of the invention, the electrolyte comprises, by weight, 12.5-15 parts of lithium salt, 3 parts of a gassing inhibitor additive, 77-86 parts of a solvent and 0.5-5 parts of a negative electrode film forming additive. In some embodiments of the invention, the gassing-suppressing additive is a phenylvinyl sulfone and an alkylene containing disilane compound. In some embodiments of the invention, the lithium salt comprises lithium hexafluorophosphate. In some embodiments of the invention, the solvent comprises at least on