Electrolyte solution and lithium-ion secondary battery

Abstract

The invention discloses an electrolyte solution and a lithium-ion secondary battery. The electrolyte solution comprises an aprotic organic solvent, electrolyte lithium salt and an additive, wherein the additive is cyclic phosphoric anhydride; and the mass of the additive accounts for 0.01-10 percent of the total mass of the electrolyte solution. The lithium-ion secondary battery comprising the electrolyte solution can be subjected to electrochemical oxidation polymerization under the voltage of over 4.4V (vs.Li / Li+). By forming a polymer on the surface of a positive pole material, a good barrier is formed to cover strongly-oxidative active points of the positive pole material, and decomposition of a main solvent of the lithium-ion secondary battery is inhibited, so that the stability of the electrolyte solution under a high-voltage state and the high-voltage cycle and storage performances of a lithium-ion battery are improved.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and in particular relates to an electrolyte and a lithium ion secondary battery using the electrolyte. Background technique [0002] Lithium-ion battery is currently the most promising high-energy green secondary battery. The non-aqueous electrolyte is a key component of lithium-ion batteries, which contains aprotic solvents, electrolyte lithium salts, and additives. It plays the role of transporting lithium ions in lithium-ion secondary batteries and is the link between the positive and negative electrode materials in the battery system. bridge. At present, the market has put forward higher and higher requirements for the energy density of lithium-ion batteries, but because the electrolyte of ordinary lithium-ion batteries is >4.5V (vs.Li / Li + ) voltage, the main solvent is strongly decomposed to generate a large amount of gas, which deteriorates the cycle performance of the lithium-ion...

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Problems solved by technology

[0003] Specifically, in order to improve the cycle performance and storage characteristics of positive and negative materials, Chinese patents 200710198735.X and 201010003990.6 propose the use of ester compounds, carboxylic anhydrides, sulfone compounds, disulfonic anhydrides, cyclic sulfonic anhydrides, phosphoric acid compounds, etc.), but none of them It does not relate to the application of a kind of cyclic phosphoric anhydride in electrolyte and lithium-ion secondary battery, especially it is not used as high-voltage lithium-ion secondary battery electrolyte additive to improve high-voltage positive electrode materials (such as LiNi 0.5 mn 1.5 o 4 ) high temperature cycle performance and charge retention

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