Non-aqueous electrolyte of silicon-based anode lithium ion battery

Abstract

The invention aims to provide a non-aqueous electrolyte of a silicon-based anode lithium ion battery with excellent charging and discharging cycle and high-temperature storage performance. The non-aqueous electrolyte consists of a solvent, a lithium salt, an unsaturated siloxanes additive A and a fluoro-sulfimide additive B, wherein the proportion, relative to the total weight of the non-aqueous electrolyte, of the additive A is 0.1% to 3%; the proportion, relative to the total weight of the non-aqueous electrolyte, of the additive B is 0.1% to 10%; the solvent comprises cyclic carbonate and / or chain carbonate; and the molar concentration of the lithium salt in the solvent is 0.8 to 1.5 mol / L. According to the non-aqueous electrolyte provided by the invention, the high and low temperature performance and the cycle performance of the silicon-based anode lithium ion battery can be comprehensively promoted. The non-aqueous electrolyte can be applied to the field of lithium ion batteries.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a non-aqueous electrolytic solution of a silicon-based negative electrode lithium ion battery. Background technique [0002] Lithium-ion batteries are widely used in 3C electronic devices due to their high working voltage, high energy density, environmental friendliness, stable cycle and safety, and their applications in pure electric and hybrid vehicles are growing rapidly. The demand for lithium-ion battery capacity in new applications continues to increase. Silicon-based anode materials are one of the effective ways to solve this problem. Its lithium storage capacity is higher than that of pure graphite anodes and the raw materials are very abundant. [0003] In actual use, the silicon-based negative electrode material of a lithium-ion battery is accompanied by a huge volume change due to the intercalation and extraction of lithium, which will cause material pulverization,...

AI Technical Summary

Problems solved by technology

[0003] In actual use, the silicon-based negative electrode material of lithium-ion batteries is accompanied by a huge volume change due to the intercalation and extraction of lithium, which will cause material pulverization, cracks, and peeling off from the conductive agent, which directly affects the cycle performance of silicon-based negative electrode lithium-ion batteries. rapid descent

In order to improve the cycle of silicon-based negative electrode lithium-ion batteries, fluorocarbonate additives are usually added for negative electrode film formation, but the film structure will be broken during the cycle, resulting in the rapid consumption of fluorocarbonate during the continuous film formation process.

In addition, the high-temperature performance of fluorocarbonate additives is poor, and gas is easily generated after high-temperature storage, which leads to battery expansion and a decrease in the capacity retention rate and capacity recovery rate of the battery.

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