Silicon negative electrode lithium battery electrolyte

Abstract

The invention relates to a silicon negative electrode lithium battery electrolyte comprising a lithium salt, a solvent and an additive, the molar concentration of the lithium salt is 0.005-3 mol / L, the additive comprises following components by mass: 10-30 parts of triethoxy methyl trimethoxysilane isocyanate, 10-20 parts of sodium ethoxylated alkyl sulfate, 5-10 parts of biphenyl, 5-10 parts of cyclohexyl benzene, 2-8 parts of fatty alcohol polyoxyethylene ether, 2-8 parts of tert amylbenzene and 2-6 parts of adiponitrile; and the solvent is a mixture of one or a plurality of substances of fluoro carboxylic ester, a carbonate organic solvent and an ether organic solvent. The silicon negative electrode lithium battery electrolyte can improve the cycle life of an electrode, reduces side reaction, thereby reducing battery gas expansion and prolonging the cycle life of a battery.

Description

technical field [0001] The invention relates to an electrolyte solution for a silicon negative electrode lithium battery, belonging to the technical field of lithium batteries. Background technique [0002] Lithium-ion batteries have the advantages of high working voltage, large specific energy, no pollution, no memory effect, and long life. They are widely used in portable electrical devices such as mobile phones, digital cameras, and notebook computers. At the same time, they are used as an alternative energy source for petroleum in electric vehicles. And hybrid vehicles will also be applied on a large scale. Silicon anode has a large lithium storage capacity and is abundant in the earth, making it an ideal anode material for lithium-ion batteries. Using a silicon negative electrode as the negative electrode of a lithium-ion battery, during the charge-discharge cycle, the reversible formation and decomposition of the Li-Si alloy is accompanied by a huge volume change, whi...

AI Technical Summary

Problems solved by technology

Using a silicon negative electrode as the negative electrode of a lithium-ion battery, during the charge-discharge cycle, the reversible formation and decomposition of the Li-Si alloy is accompanied by a huge volume change, which will cause the powdering or cracking of the alloy, resulting in the collapse of the silicon material and the electrode material. The peeling off of the electrode material causes the electrode material to lose electrical contact, resulting in a sharp decline in the cycle performance of the silicon negative lithium-ion battery

At the same time, due to the occurrence of side reactions, a large amount of gas will be generated during the charging and discharging process, and it is easy to swell inside the battery.