Preparation method and application of low-temperature electrolyte additive

Abstract

The invention relates to a preparation method of a low-temperature electrolyte additive. The preparation method comprises the following steps: firstly, carrying out condensation reaction on aldehyde and triphenylphosphine salt to prepare a trifluoromethyl olefin derivative containing double bonds; oxidizing the double bonds of the trifluoromethyl olefin derivative by using an oxidation reaction of peroxide; then further conducting hydrolyzing under a strong alkali condition to prepare a trifluorodihydroxy alcohol molecule containing two ortho-hydroxyl groups; and finally, obtaining the low-temperature electrolyte additive through phosgene cyclization. The molecular structure of the multi-trifluoromethylation additive developed by the invention is relatively simple, especially when a synthetic route is designed, the fluorination reaction conditions are mild, the operation is simple and convenient, the requirements on instruments and equipment are low, long-chain alcohol is used as a reaction raw material, the price is low, the source is wide, the yield of the prepared compound is high, and when the multi-trifluoromethylation additive is used as the additive to be applied to a graphite-LiCoO2 battery system, the material has excellent high- and low-temperature resistance, and has good cyclicity in a range of -55 to 55 DEG C.

Description

technical field [0001] The invention relates to the technical field of lithium battery additive synthesis, in particular to a preparation method and application of a low-temperature electrolyte additive. Background technique [0002] With the increasing application fields of lithium-ion batteries, the working conditions that lithium-ion batteries need to face are becoming more and more stringent, such as working temperature, working voltage and working humidity. At present, the limit operating temperature of lithium-ion batteries is between -20 and 60°C, which just meets the requirements of low-power electrical equipment for the operating temperature of the power supply. However, there are large temperature differences between the north and the south of my country and seasonal changes. The lithium-ion batteries of electric vehicles and hybrid vehicles need to output stably in the temperature range of -30 to 70°C for a long time. However, in northern my country, the performa...

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Problems solved by technology

However, in northern my country, due to seasonal low temperature, the battery performance is reduced. To solve the problem of using lithium-ion batteries in a multi-temperature environment, we must start with the optimized design of the electrolyte.

However, in the researches reported so far, the electrolyte additives for lithium-ion batteries are all alkane derivative additives, and there is no obvious improvement in improving the performance of the electrolyte at wide temperature, especially at low temperature.

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