Preparation method of lithium difluorophosphate

Abstract

The invention discloses a preparation method of lithium difluorophosphate. The preparation method comprises the following steps: (1) carrying out esterification reaction on phosphorus oxychloride and monohydric alcohol to obtain dichlorophosphate; (2) carrying out a fluorination reaction on the dichlorophosphate and a fluorination reagent in the presence of a solvent to obtain difluorophosphate; and (3) carrying out lithiation reaction on the difluorophosphate and a lithiation reagent in the presence of a solvent to prepare the lithium difluorophosphate. The preparation method of the lithium difluorophosphate has the advantages of easily available preparation raw materials, low cost, simple and feasible method, mild reaction conditions, low equipment requirements and high reaction safety, and is suitable for large-scale industrial production.

Description

A kind of preparation method of lithium difluorophosphate technical field [0001] The present invention relates to the technical field of batteries, and more particularly to a method for preparing lithium difluorophosphate. Background technique [0002] With the growing demand for new energy vehicles and energy storage devices, the demand for lithium-ion batteries increases year by year; Sub-battery is mainly used in digital products, electric vehicles, power storage and other fields. Lithium-ion batteries require high energy density It has the characteristics of high temperature, long cycle life, good high and low temperature performance and good safety. can be added to lithium-ion battery electrolytes Appropriate additives to optimize and improve the performance of lithium-ion batteries. As a lithium salt additive, lithium difluorophosphate has excellent electrochemical properties and can improve the cycle of the battery. life, high and low temperature performance...

AI Technical Summary

Problems solved by technology

[0004] The existing preparation of lithium difluorophosphate mainly involves the decomposition of lithium hexafluorophosphate to obtain lithium difluorophosphate. Chinese patent CN106829910A uses lithium hexafluorophosphate and lithium carbonate to react to prepare lithium difluorophosphate. This method will produce a large amount of lithium fluoride by-products, from the system It is relatively difficult to separate lithium fluoride from the lithium fluoride, and the atom economy is relatively poor; Chinese patent CN106976853A uses lithium hexafluorophosphate and siloxane to react to produce lithium difluorophosphate. Poor performance, expensive raw materials, high production cost

[0005] At present, phosphorus oxychloride is also used to prepare lithium difluorophosphate. For example, Chinese patent CN106458589A provides a synthesis of lithium difluorophosphate by using phosphorus oxychloride. The method has cheap raw materials and good atom economy, but the method needs to use high Dangerous anhydrous hydrofluoric acid has extremely high requirements on equipment and staff

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