Electrolyte additive, high-voltage electrolyte and lithium ion battery containing electrolyte additive

Abstract

The invention discloses an electrolyte additive, a high-voltage electrolyte and a lithium ion battery containing the electrolyte additive. The high-voltage electrolyte is prepared by adding the electrolyte additive into the conventional electrolyte; the conventional electrolyte comprises a non-aqueous organic solvent and lithium salt, wherein the content of the non-aqueous organic solvent is 80-85 percent of the total mass; the mass of the electrolyte additive is 0.01-10 percent of the total mass; and the electrolyte additive is maleic anhydride C4H2O3 or one of derivatives thereof and has the structure formula as shown in the abstract. According to the high-voltage electrolyte, a stable interfacial film can be formed on the surfaces of a positive electrode and a negative electrode, the reaction activity on the electrode surface is inhibited, oxidative decomposition of the electrolyte is reduced, and gas swelling is effectively inhibited, so that the safety performance and the cycle performance of the lithium ion battery under normal pressure and high voltage are improved and the service life of the lithium ion battery under normal pressure and high voltage is prolonged. The electrolyte is simple in preparation process and is suitable for industrial production.

Description

technical field [0001] The present invention relates to a kind of can improve lithium ion battery in 3~4.5VLi / Li + Electrolyte additives with low cycle performance and service life and high-voltage electrolytes and lithium-ion batteries containing the electrolyte additives. Background technique [0002] In recent years, with the popularization of portable electronic devices, the development of electric tools and electric vehicles, lithium-ion batteries as a new generation of high-energy power sources have attracted extensive attention. At present, the positive electrode materials of commercial lithium-ion batteries mainly include lithium manganese oxide, lithium cobalt oxide, ternary materials, lithium iron phosphate, etc., and the charging cut-off voltage generally does not exceed 4.2V. However, the development of the market has put forward higher requirements for lithium-ion batteries - on the basis of ensuring or improving the original energy density, it is increasingly ...

AI Technical Summary

Problems solved by technology

However, as the voltage increases, the conventional electrolyte will oxidize and decompose on the surface of the positive electrode material in addition to its own oxidative decomposition reaction. The positive electrode material containing transition metal elements plays a catalytic role to promote the oxidation of the electrolyte. Eventually, the internal resistance of the battery will increase, the cycle performance will be destroyed, and the service life of the battery will be shortened.

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