Wide-temperature type lithium ion battery electrolyte and lithium ion battery containing electrolyte

Abstract

The invention belongs to the technical field of lithium ion batteries, and discloses a wide-temperature type lithium ion battery electrolyte and a lithium ion battery containing the electrolyte. The wide-temperature type lithium ion battery electrolyte comprises a lithium salt, an organic solvent and an additive, and the additive comprises a chain-like acyl sulfonate compound with a structure shown in a formula I or a cyclic acyl sulfonate compound with a structure shown in a formula II, the acyl sulfonate additive can be simply regarded as an anhydride compound formed by dehydration of carboxylic acid and a sulfonic acid group, has both the anhydride group and the sulfonic acid group, can form an SEI membrane component with a lithium alkyl sulfonate or lithium alkyl sulfate structure, isresistant to high temperature, can improve the high-temperature stability of the lithium ion battery, is low in impedance and has a good low-temperature effect, and the normal-temperature and low-temperature cycle performance of the lithium ion battery can be improved.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a wide-temperature lithium-ion battery electrolyte and a lithium-ion battery containing the electrolyte. Background technique [0002] In lithium-ion battery electrolytes, sulfur-containing additives are widely used and have excellent performance, such as commonly used DTD, MMDS, PS, PST, TS and other electrolyte additives. ester group. According to literature (ACS Appl. Energy Mater. 2018, 1, 2582-2591), sulfur-containing additives are easily oxidized or reduced on the electrode surface to produce alkyl lithium sulfate, alkyl lithium sulfite, lithium sulfite, etc., which have good High temperature stability or lower impedance performance. However, it is difficult for the same sulfur-containing additive to meet the requirements of low temperature and high temperature at the same time. Such as PS, PST, etc., although they can improve the high temperature effect, b...

AI Technical Summary

Problems solved by technology

[0003] It is precisely because of the defects of the above-mentioned commonly used additives that a major problem faced by lithium-ion batteries is that they cannot take into account both high and low temperatures, that is, they cannot have excellent chemical properties at both high and low temperatures

Under high temperature conditions, because the electrolyte in lithium-ion batteries is easy to catalyze and decompose on the surface of the positive electrode, resulting in battery flatulence and reduced capacity, etc., it is necessary to add additives with excellent positive electrode film-forming properties to complex metal ions and passivate positive active sites. etc., but the addition of such additives will lead to a significant increase in battery impedance, seriously affecting the rate performance of the battery and the low-temperature use effect

Images