Lithium ion battery, non-aqueous lithium ion battery electrolyte and application of fluoro sulfonic anhydride in preparation of non-aqueous lithium ion battery electrolyte

Abstract

The invention discloses a lithium ion battery, a non-aqueous lithium ion battery electrolyte and application of fluoro sulfonic anhydride in preparation of the non-aqueous lithium ion battery electrolyte. The lithium ion battery comprises a positive electrode, a negative electrode, a separator and the non-aqueous lithium ion battery electrolyte, wherein the non-aqueous lithium ion battery electrolyte comprises a non-aqueous organic solvent, an electrolyte salt and fluoro sulfonic anhydride, where the fluoro sulfonic anhydride is used as a functional additive, such as trifluoromethyl sulfonic anhydride, pentafluoroethyl sulfonic anhydride and perfluorobutyl sulfonic anhydride. The fluoro sulfonic anhydride is introduced as the functional additive and is applied to the non-aqueous lithium ion battery electrolyte and the battery, a compact and uniform SEI membrane with high lithium ion conductivity can be formed during initial formation of the battery prepared from the non-aqueous lithium ion battery electrolyte, so that the current distribution during charge-discharge period of the battery is uniform, the ion conductivity of lithium ions is improved, and the normal-temperature cycle property, the high-temperature cycle property, the high-temperature storage performance and the low-temperature cycle property of the lithium ion battery are further improved.

Description

[0001] [technical field] [0002] The invention relates to lithium batteries, in particular to the application of lithium ion batteries, nonaqueous lithium ion battery electrolytes and fluorosulfonic anhydrides in preparing nonaqueous lithium ion battery electrolytes. [0003] [Background technique] [0004] With the pursuit of small volume and high energy density of the battery, the compaction density of the positive and negative electrodes is continuously increased or the high-capacity negative electrode material with poor cycle performance is used, which also brings a series of performance problems of the battery, such as poor cycle performance, Poor high-temperature performance, poor low-temperature performance and rate performance, easy to precipitate lithium during low-temperature charge and discharge. The cause analysis of the above problems found that a layer of SEI film will be formed on the surface of the negative electrode during the first charging process of the lit...

AI Technical Summary

Problems solved by technology

In a low-temperature environment, if the formed SEI film is too thick and the film resistance is high, lithium ions cannot migrate through, and lithium precipitation will occur; during high-temperature cycling, if the formed SEI film is not dense and stable, the SEI film will Gradually dissolve or rupture, causing the exposed negative electrode to continue to react with the electrolyte, which consumes the electrolyte and reduces the battery capacity

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