Silicon-based anode lithium-ion battery electrolyte

Abstract

The invention provides silicon-based anode lithium-ion battery electrolyte which comprises an organic solvent, lithium salt, a film formation additive and a function additive, wherein the film formation additive comprises fluoro carbonic ester and tri-(pentafluorophenyl)borane, and the additive amounts of fluoro carbonic ester and tri-(pentafluorophenyl)borane respectively take 1%-15% and 0.1%-5% of the total mass of the electrolyte. According to the electrolyte, a stable, uniform and flexible SEI (solid electrolyte interface) film is formed on the surface of a silicon-based anode and can endure volume expansion of the silicon-based anode in repeated charging and discharging processes, so that the cycle performance of a battery is enhanced.

Description

[0001] 【Technical field】

[0002] The invention belongs to the technical field of lithium ion batteries, and in particular relates to an electrolyte solution for a silicon-based negative electrode lithium ion battery.

[0003] 【Background technique】

[0004] Silicon-based materials are currently the anode materials for lithium-ion batteries with the highest gram capacity. The stress caused by the large volume expansion and contraction during the lithium-deintercalation process causes a large number of microcracks in the anode, resulting in a large number of microcracks between the active material and the gap between the active material and the current collector. Poor inter-contact, which causes the peeling of the active material and the collapse of the structure, leads to a decrease in conductivity and an increase in the internal resistance of the battery. Therefore, silicon-based negative electrode lithium-ion batteries have problems such as low initial Coulombic efficiency, po...

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