Preparation method of lithium tetrafluoroborate

Abstract

The invention relates to a preparation method of lithium tetrafluoroborate. According to the technical scheme, the preparation method comprises the following steps that 1, under the ambient temperature and pressure, lithium fluoride is added into an esters solvent to obtain a lithium fluoride turbid liquid; 2, boron trifluoride gas is introduced into the lithium fluoride turbid liquid, and reaction is carried out for 1-2 h to obtain a lithium tetrafluoroborate solution; 3, unreacted trace lithium fluoride of the solution obtained in step 2 is filtered through a microporus filter; 4, the liquidafter filtration in step 3 is completed is subjected to concentration and degassing; 5, the solution after concentration is completed in step 4 is subjected to cooling crystallization, filtration anddrying to obtain a lithium tetrafluoroborate finished product. The preparation method of the lithium tetrafluoroborate has the advantages that adopted boron trifluoride is an industrial grade raw material, and is low and easy to obtain; the lithium fluoride forms the turbid liquid in the esters solvent, so that reaction is easily carried out, the operation is simple and convenient, the safety isimproved, and the problems of the risk in reaction and preparation when hydrogen fluoride is adopted as a solvent, excessive amount of free acid of the product, high energy consumption of ultralow-temperature crystallization and the like are avoided.

Description

technical field [0001] The invention relates to a preparation technology of an electrolyte material for a lithium ion battery, in particular to a preparation method of lithium tetrafluoroborate. Background technique [0002] In recent years, as the country vigorously promotes new energy vehicles and restricts the use of traditional fuel vehicles, the demand for energy other than non-petrochemical energy has increased significantly. As a green and clean energy explored and developed in the 21st century, lithium-ion batteries are widely used in the automotive field. It has been vigorously promoted and applied. With the rapid development of the application of power lithium-ion batteries, the different requirements for the environment, temperature and safety factors have put forward strict requirements on the electrolyte system. [0003] Lithium salts used in lithium-ion battery electrolytes are generally divided into lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiB...

AI Technical Summary

Problems solved by technology

The problem is that anhydrous hydrogen fluoride is a highly reactive substance, which can react with various substances, and is highly toxic, corrosive and irritating.

The existing problems are: the boron trifluoride complex is used to add lithium fluoride to the reaction, and the solid addition is difficult to control accurately, which makes the reaction process difficult to control and the safety is not high; Crystallization is extracted with a weak polar solvent, so the amount of solvent used is large, and the extracted solvent is difficult to separate and difficult to recycle.