Electrolyte and lithium ion battery

Abstract

The invention discloses an electrolyte suitable for an NCM system and a battery. The electrolyte comprises an organic solvent, electrolyte lithium salt and additives, and the additives comprise ethylene sulfate accounting for 0.1%-10% of the total mass of the electrolyte, succinic anhydride accounting for 0.1%-5% of the total mass of the electrolyte, ethyoxyl (pentafluoro) cyclotriphosphazene accounting for 0.1%-15% of the total mass of the electrolyte and diphenyl carbonate accounting for 0.01%-5% of the total mass of the electrolyte. The electrolyte and the battery provided by the invention not only have excellent electrochemical performance at normal temperature and high temperature, but also are obviously improved in the aspects of overcharge and flame retardance; therefore, the material has a wide application prospect in batteries of high-energy density systems in the future.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to an electrolyte solution and a lithium ion secondary battery. Background technique [0002] Lithium-ion battery cathode materials, such as NCM ternary materials, have the advantages of high specific capacity, good cycle performance, good safety and low environmental pollution, etc., gradually attracting people's attention, and are expected to become one of the mainstream cathode materials for lithium-ion batteries in the future. In order to meet people's demand for high energy density, NCM ternary cathode materials are also developing in two directions: 1) high nickel, higher Ni content can bring higher capacity; 2) high voltage, increased voltage On the one hand, it can increase the capacity of the material, and on the other hand, it can also increase the voltage platform of the material. However, as the charging voltage increases, the stability of the positive ele...

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Problems solved by technology

[0005] Chinese patent CN104659417B discloses that the high-voltage electrolyte contains fluorocarbonate compounds, fluoroether compounds, lithium oxalate difluoroborate, and lithium hexafluorophosphate; It is easy to decompose and produce VC and hydrofluoric acid, and hydrofluoric acid will corrode the SEI film formed on the surface of the electrode, deteriorating the electrical performance of the battery

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