Lithium-ion battery and its electrolyte

Abstract

The invention discloses a lithium ion battery and an electrolyte thereof. The electrolyte of the lithium ion battery comprises a non-aqueous organic solvent, a lithium salt, and an additive, wherein the additive comprises a linear sulfonate compound containing a cyano group and represented by the formula (I). In the formula (I), R represents an alkyl group or a halogenated alkyl group containing 1-8 carbon atoms, an aryl group containing 6-9 carbon atoms, or an aralkyl group containing 7-10 carbon atoms; and X and Y independently represent a cyano group, an ethylcyano group, and a propylcyano group, respectively. The electrolyte of the lithium ion battery can form a stable SEI membrane, and can form complexation with high-valence metal ions on an anode surface, thereby effectively slowing the decomposition reaction of the electrolyte on anode and cathode surfaces, and improving the storage performance of the lithium ion battery at a high temperature and under a high pressure.

Description

technical field [0001] The invention belongs to the field of lithium-ion batteries, and more specifically, the invention relates to a lithium-ion battery with ideal high-temperature and high-pressure storage performance and an electrolyte thereof. Background technique [0002] Lithium-ion batteries have the advantages of high working voltage, high specific energy, and good cycle performance, so they are widely used in various portable electronic devices such as mobile communications and digital cameras, and gradually expand to the application fields of energy storage power supply and power battery. . In recent years, the performance of electronic products such as smartphones and tablet computers has been greatly improved, and higher requirements have been placed on the energy density of lithium-ion batteries. [0003] The use of high-voltage cathode materials is an important direction to improve the energy density of lithium-ion batteries. However, an important problem fac...

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Problems solved by technology

[0008] The purpose of the present invention is to provide an electrolyte that can improve the high-temperature and high-pressure storage performance of lithium-ion batteries and a lithium-ion battery containing the electrolyte, so as to overcome the shortcomings of large thickness expansion and rapid capacity loss during high-temperature and high-pressure storage of existing lithium-ion batteries

[0009] The inventors of the present application have found through long-term careful research that by adding a linear sulfonate compound containing cyano groups to the non-aqueous electrolyte, the shortcomings of large thickness expansion and rapid capacity loss during high-temperature and high-pressure storage of existing lithium-ion batteries can be overcome

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