Electrolyte solution of fluorine-containing lithium sulfonimide salt and application thereof

Abstract

The invention provides an electrolyte solution of fluorine-containing lithium sulfonimide salt and application of the electrolyte solution. The electrolyte solution consists of the following four components: fluorine-containing lithium sulfonimide, other lithium salts, carbonate and / or ether organic solvent and other functional addictives, wherein the molar concentration of fluorine-containing lithium sulfonimide salt is 0.001-2 mole / L in the electrolyte solution, the molar concentration of other lithium salts is 0-2 mole / L in the electrolyte solution, and the molar concentration of other functional addictives is 0-0.5 mole / L; and the fluorine-containing lithium sulfonimide is an ion-type compound, wherein the cation is lithium ion. The fluorine-containing lithium sulfonimide is contained in the electrolyte solution provided by the invention, thus the low temperature property of the electrolyte solution is improved greatly; and after the electrolyte solution is applied to a lithium battery, the capacity percentage of the lithium battery is improved at the high temperature more than 50 DEG C or at the low temperature below minus 20 DEG C, which is beneficial to improving the cycle life and the storage life of the lithium battery.

Description

technical field [0001] The invention relates to an electrolyte solution containing fluorine-containing sulfonylimide lithium lithium salt and an application thereof, belonging 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 electrochemi...

AI Technical Summary

Problems solved by technology

[0005] In summary, using LiPF 6 The low-temperature performance of secondary lithium batteries that are conductive salts is difficult to meet actual needs

When the ambient temperature is as low as minus 40 degrees or even lower, the battery cannot fully release its full capacity, or even fail to work normally, thus limiting the application of secondary lithium batteries in extreme temperature conditions

When the temperature is lowered, the current LiPF 6 Part of the commercial electrolyte solution as a conductive salt will crystallize or solidify, the viscosity will increase, the conductivity will drop sharply, and the interface impedance between the electrolyte and the electrode will increase greatly, resulting in a sharp decline in battery performance and even causing the battery to fail to work.

Images