Electrolyte and secondary battery

Abstract

The invention provides an electrolyte and a secondary battery. The electrolyte comprises an electrolyte salt, an organic solvent and an additive. The additive comprises a cyclotriphosphazene compoundand vinyl ethylene carbonate. When the electrolyte is applied to a secondary battery, the normal temperature cycle performance, high temperature storage performance and high temperature thermal stability of the secondary battery can be improved simultaneously.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to an electrolyte solution and a secondary battery. Background technique [0002] Due to the characteristics of high energy density, long cycle life and no pollution, secondary batteries, especially lithium-ion secondary batteries, have broad application prospects in consumer electronics, power vehicle batteries and energy storage power supplies. [0003] Regardless of the application field, people have put forward higher requirements for the battery life of lithium-ion secondary batteries. In order to improve the energy density of lithium-ion secondary batteries, the development of positive electrode active materials with high specific capacity is one of the effective methods. At present, transition metal oxide cathode active materials have become a research hotspot due to their higher theoretical specific capacity than other cathode active materials. However, the transition me...

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Problems solved by technology

However, the transition metal oxide positive electrode active material has a strong oxidizing property in a high SOC state, which causes the electrolyte to easily undergo electrochemical oxidation reaction on the surface of the positive electrode, and at the same time causes a change in the structure of the transition metal oxide positive electrode active material, resulting in nickel, cobalt , manganese and other transition metals undergo a reduction reaction and dissolve, which causes the deterioration of the electrochemical performance of the lithium-ion secondary battery

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