Lithium-ion battery electrolyte and preparation method thereof

Abstract

The invention discloses a lithium-ion battery electrolyte. The lithium-ion battery electrolyte is prepared from, by mass, 70-85% of an organic solvent, 5-15% of LiPF6 and 10-15% of an additive, wherein the total content of all the components accounts for 100%. The invention further discloses a preparation method of the lithium-ion battery electrolyte. The method comprises the steps that 1, the organic solvent, the LiPF6 and the additive are weighed respectively according to the mass percentage; 2, the organic solvent, the LiPF6 and the additive are sequentially added in a glove box inflated with argon gas and then sufficiently stirred to be uniform to obtain the lithium-ion battery electrolyte, wherein the concentration of H2O is smaller than 50 ppm. According to the method, the problem that battery electrolyte and graphite negative electrode are subjected to solvation lithium-ion cointercalation is solved, the first-time charging and discharging efficiency of a lithium-ion battery is improved, the battery cycle life is prolonged, and meanwhile a phosphate group is introduced into the additive, so that the electrolyte is retardant to fire, the safety of the electrolyte is improved, and the lithium-ion battery electrolyte is suitable for large-scale industrial production.

Description

technical field [0001] The invention belongs to the technical field of chemical power sources, and relates to a lithium-ion battery electrolyte, and also relates to a preparation method of the lithium-ion battery electrolyte. Background technique [0002] The rapid development of lithium-ion battery technology, especially the wide application in the electric vehicle industry, the high capacity, high voltage, long service life and safety issues of the battery have prompted the emergence of positive and negative electrodes, electrolytes, and diaphragm materials for lithium-ion batteries. out of diversity. At present, the preparation process of lithium-ion battery electrolyte uses high-purity LiPF 6 It is compounded with commonly used electrolyte systems, commonly used electrolyte systems include ethylene carbonate and dimethyl carbonate electrolyte systems, ethylene carbonate and diethyl carbonate electrolyte systems, ethylene carbonate and dimethyl carbonate electrolyte syst...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a lithium-ion battery electrolyte, which solves the problem of poor compatibility between the lithium-ion battery electrolyte and graphite-based negative electrode materials in the prior art, and the co-intercalation of solvated lithium ions is prone to occur, causing the graphite layer to peel off and affecting lithium ions. The first charge and discharge efficiency of the battery and the cycle life of the battery; at the same time, the addition of phosphate groups in the electrolyte greatly shortens the self-extinguishing time of the electrolyte when it burns, that is, the electrolyte becomes flammable and thus improves the safety of the electrolyte

[0004] Another object of the present invention is to provide the preparation method of the above-mentioned lithium-ion battery electrolyte, which solves the problems of low initial charge and discharge efficiency and poor cycle life of the battery electrolyte in the existing battery electrolyte preparation method