Ternary high-voltage lithium ion battery electrolyte and ternary high-voltage lithium ion battery

Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a ternary high-voltage lithium ion battery non-aqueous electrolyte and a ternary high-voltage lithiumion battery. The electrolyte comprises a non-aqueous organic solvent, an electrolyte lithium salt and additives, wherein the additives comprise a conventional additive and a sulfate additive with a structure as shown in the formula (I). Compared with the prior art, the combine defect of the conventional additive and the sulfate additive with a structure as shown in the formula (I) is utilized, sothat film forming can be achieved on the surface of the positive electrode material, the generation of cracks in the particles in the circulation process of the positive electrode material particlesis inhibited, and the dissolution of the transition metal elements at a high temperature is reduced; an SEI film can be formed on the surface of the negative electrode material, and the reduction reaction of the solvent on the negative electrode interface can be inhibited; and meanwhile, the interface impedance can be reduced, so that the cycling performance, the high-temperature storage performance and the low-temperature performance of the ternary high-voltage lithium ion battery are effectively improved.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a ternary high-voltage lithium-ion battery electrolyte and a ternary high-voltage lithium-ion battery. Background technique [0002] Lithium-ion batteries are widely used in 3C digital products, power tools, electric vehicles, aerospace and other fields due to their high operating voltage, high energy density, long life, wide operating temperature range, and environmental friendliness. Especially in the 3C digital field, in recent years, mobile electronic devices, especially smart phones, have been developing rapidly towards lighter and thinner, which puts forward higher requirements for the energy density of lithium-ion batteries. [0003] In order to increase the energy density of lithium-ion batteries, a common measure is to increase the charging medium voltage of the positive electrode material, such as the commercial lithium cobalt oxide battery voltage from 4....

AI Technical Summary

Problems solved by technology

However, there will be certain defects in the positive electrode material under high voltage. For example, the high-voltage positive electrode active material has a strong oxidation property in the lithium-deficient state, which makes the electrolyte easy to be oxidized and decomposed, and produces a large amount of gas; in addition, the high-voltage positive electrode The active material itself is also very unstable in the state of lithium deficiency, and some side reactions are prone to occur, such as the release of oxygen, the dissolution of transition metal ions, etc., causing the transition metal ions to break away from the crystal and enter the electrolyte as the reaction progresses to catalyze the decomposition and dissolution of the electrolyte. Damage the passivation film of the active material, and transition metal lithium ions will also occupy the lithium ion migration channel of the passive film on the surface of the negative electrode material, hindering the migration of lithium ions, thereby affecting the service life of the battery. This negative effect will be more pronounced when used under

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