Electrolyte and lithium ion battery comprising same

Abstract

The invention relates to an electrolyte and a lithium ion battery comprising the same. The electrolyte comprises a lithium salt, an organic solvent, an additive A and an additive B; the additive A isa phosphonic acid cyclic anhydride compound; and the additive B is an organic compound comprising one or more of an imide group, a carbodiimide group and a cyano group. The electrolyte comprises the additive A and the additive B, so that when the electrolyte is applied to the lithium ion battery, the cycle performance of the lithium ion battery is improved, and particularly, the cycle performanceof the lithium ion battery at a relatively high temperature of 45 DEG C is improved; and in addition, the storage performance of the lithium ion battery at a high temperature also can be improved.

Description

technical field [0001] The present application relates to the technical field of lithium ion batteries, and in particular, to an electrolyte and a lithium ion battery including the electrolyte. Background technique [0002] In recent years, with the rapid development of intelligent electronic products, higher requirements have been placed on the battery life of lithium-ion batteries. In order to improve the energy density of lithium-ion batteries, the development of high-voltage lithium-ion batteries is one of the effective methods. [0003] At present, lithium-ion batteries with working voltages above 4.35V have become the research hotspots of many scientific research institutes and enterprises. However, under high voltage, the oxidation activity of the cathode material increases and the stability decreases, which leads to the easy electrochemical oxidation reaction of the non-aqueous electrolyte on the surface of the cathode, and then decomposes to generate gas. At the s...

AI Technical Summary

Problems solved by technology

These additives can form a film on the positive electrode, but it will increase the interfacial impedance, resulting in a decrease in the kinetics of lithium ion migration and diffusion in the battery, which in turn will reduce the rate and cycle performance of the battery.