Superlow-temperature lithium ion battery electrolyte and lithium ion battery using same

Abstract

The invention discloses a superlow-temperature lithium ion battery electrolyte. The electrolyte is prepared from the following raw materials of organic solvents, lithium salt and a film forming additive, wherein the organic solvents comprise carbon disulfide, ethyl butyrate, diglyme and N,N-dimethylformamide; the lithium salt is lithium tetrafluoroborate; the film forming additive consists of vinylene carbonate and any one of ethylene sulfate, lithium difluorophosphate and imidodisulfuryl fluoride. Compared with t traditional carbonate solvents, the electrolyte has the advantages that the melting point of the used organic solvent is very low, and the higher ion conductivity is still maintained at superlow temperature of -40 DEG C; the additive forms a film at the surface of a cathode, andcan form a stable SEI (solid electrolyte interface) film with low impedance, so as to quickly intercalate and de-intercalate the lithium ions at low temperature. The invention also discloses the lithium ion battery using the electrolyte. The lithium ion battery can reach excellent low-temperature discharge and cycle properties under the superlow-temperature environment.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to an ultra-low temperature lithium ion battery electrolyte and a lithium ion battery using the electrolyte. Background technique [0002] Due to its high operating voltage, high specific energy density, long cycle life, and environmental friendliness, lithium-ion batteries have become one of the indispensable and important chemical power sources in the fields of electronic digital, electric vehicles, energy storage applications, aerospace and other fields. Electrolyte is one of the four main materials of lithium-ion batteries. It is called the "blood" of lithium-ion batteries. It is usually composed of lithium salts, solvents and additives. It is important for the cycle performance, rate performance and safety performance of lithium-ion batteries. Impact. Since the electrolyte should meet the requirements of compatibility with positive and negative materials, physica...

AI Technical Summary

Problems solved by technology

However, the low-temperature electrolyte reported so far is still based on the existing carbonate-based solvents. Although it can improve battery performance under general low-temperature environmental conditions, it still cannot work effectively under ultra-low temperature conditions below -40°C. Therefore, the further development of a new type of ultra-low temperature electrolyte system is of great significance to broaden the application range of lithium-ion batteries and improve the application value under extreme conditions.

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