Non-aqueous electrolyte solution of fluorine-containing compound

Abstract

The invention discloses a non-aqueous electrolyte solution of a fluorine-containing compound. The non-aqueous electrolyte solution comprises a lithium salt, the fluorine-containing compound, a carbonate and / ether organic solvent, and an additive having other functions, wherein the molar concentration of the lithium salt in the electrolyte solution is 0.001-2mol / L, the mass percentage of the fluorine-containing compound in the electrolyte solution is 0.01-90%, the mass percentage of the carbonate and / ether organic solvent in the electrolyte solution is 0-90%, and the molar concentration of the additive having other functions in the electrolyte solution is 0-0.5mol / L. The non-aqueous electrolyte solution provided in the invention can inhibit the decomposition of battery materials, increase the cycle life and the service life of a lithium battery, inhibit the improvement of the resistance of the battery, improve the capacity retention rate of the battery, and improve the capacity retention rate and the cycle life of the battery in a high temperature environment.

Description

technical field [0001] The invention relates to a nonaqueous electrolyte solution, which belongs to the technical field of chemical materials. Background technique [0002] At present, commercial lithium battery electrolytes are mainly composed of organic carbonates such as dimethyl carbonate (DMC for short), diethyl carbonate (DEC for short), ethylene carbonate (EC for short), etc., and conductive salts (mainly LiPF 6 )composition. The optimization and selection of organic carbonate non-aqueous electrolyte solutions is one of the important research directions to improve the comprehensive performance of lithium-ion batteries. Non-aqueous electrolyte solutions used in lithium-ion batteries should generally meet the following requirements: (1) high ion conductivity, generally should reach 10-3S / cm; (2) high lithium ion migration number to obtain high lithium ion conductivity (3) The electrochemical window is wide, that is, to meet the reversible intercalation and extraction ...

AI Technical Summary

Problems solved by technology

However, in the above-mentioned technologies, it is impossible to obtain a sufficient film effect relative to the increase in battery characteristics. First, the surface film deteriorates and the function decreases when it is used repeatedly; Different degrees of decomposition occur, leading to irreversible changes in the composition and properties of the coating, which seriously affects battery performance

In a series of patents such as CN101154753A, it is mentioned that adding compounds such as 1,3-dioxane to the electrolyte can inhibit the decomposition of the solvent and improve the cycle life of the battery, but the decomposition of compounds such as 1,3-dioxane It will significantly increase the interface impedance on the positive side, which will cause loss of battery performance

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