Electrolyte with high flame retardation performance and electrochemical performance and lithium ion battery

Abstract

The invention discloses electrolyte with a high flame retardation performance and an electrochemical performance for a lithium ion battery. The electrolyte comprises a solvent, lithium salt, a flame retardant and an additive, wherein the additive is one or several of halogenated organic compound, cyclic carbonate compound comprising unsaturated bonds or non-symmetrical chain carbonate ester compound comprising unsaturated bonds, the dosage of the lithium is 0.6-1.5mol/L, the dosage of the flame retardant occupies 1-70% of the total mass of the electrolyte, and the dosage of the additive occupies 0.1-15% of the total mass of the electrolyte. According to the electrolyte disclosed by the invention, by adding the flame retardant in the electrolyte for the lithium ion battery and adding the additive which can be used for restraining the flame retardant from degrading the electromechanical performance of the electrolyte at the same time, thus the electrolyte has the flame retardation performance or non-inflammability, the safety performance of the battery is improved, the influence on the electromechanical performance of the battery due to the flame retardant is overcome, and the battery performance is excellent.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to an electrolyte with high flame retardancy and electrochemical performance and a lithium ion battery using the electrolyte. Background technique [0002] Due to the advantages of high energy density, high output voltage, long cycle life, and low environmental pollution, lithium-ion batteries have extremely important applications in the fields of electronic products, electric vehicles, aerospace, and energy storage. However, in recent years, there have been frequent reports of fires and even explosions caused by lithium-ion batteries, and the safety of lithium-ion batteries has attracted widespread attention. At the same time, safety issues are also a bottleneck restricting the development of lithium-ion batteries in the direction of large-scale and high-energy. [0003] The most important components of a lithium-ion battery are the positive and negative electrode mat...

AI Technical Summary

Problems solved by technology

US patents US 6,589,697, US 6,924,061, and US 6,589,697 reported that flame retardants such as trimethyl phosphate (TMP), tributyl phosphate (TBP), triphenyl phosphate (TPP), and trifluoroethyl phosphate were added to the electrolyte , but these additives cannot be used alone as a solvent in large quantities due to their shortcomings such as high viscosity and high freezing point. Even when used as an additive in a small amount, the amount should be controlled within a certain limit

When its dosage is large, although it has a good flame retardant effect on the flame retardant performance of the electrolyte, it will cause a large negative impact on the electrochemical performance of the electrolyte; US Patent US 6,455,200 uses hexamethoxyphosphazene as the liquid flame retardant, but its flame retardant efficiency is low; Chinese patents CN 101017917A, CN 101079504B and CN 101079505B use dimethyl methyl phosphate (DMMP) as a flame retardant or solvent. When the mass percentage of DMMP is greater than 10%, It can make the electrolyte non-flammable, but it will obviously deteriorate the electrochemical performance of the battery (such as rate performance, cycle performance, etc.)

[0005] None of the above reports take into account the flame retardant performance of the electrolyte and overcome its damage to the electrochemical performance.

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