Preparation method of lithium hexafluorophate

Abstract

The invention discloses a preparation method of lithium hexafluorophate. The preparation method includes preparing gas mixture of phosphorus pentafluoride and hydrogen chloride; preparing anhydrous hydrogen fluoride mixed liquor containing lithium fluoride; realizing combination reaction of the gas mixture and the mixed liquor; realizing quick cooling crystallization of lithium hexafluorophate liquor; separating solid from liquid; realizing rotary vacuum drying; and finally obtaining lithium hexafluorophate crystal. The preparation method is a high-efficiency gas, solid and liquid three-phasereaction method, purity of the quality of products is guaranteed, simultaneously, yield further can be increased, the yield of the products can reach 90% at least, moisture and metal impurities in the products are effectively reduced, zero emission of the phosphorus element can be realized in aftertreatment, requirements of current national environmental protection policy are met, byproducts of hydrochloric acid and hydrofluoric acid can be sold to bring certain income, production cost is further lowered, the quality of the products is further improved by means of adopting high-specification equipment and materials, requirements of high-end electrolyte products can be met, and the preparation method has excellent practicality and can produce good economic benefit and social benefit.

Description

technical field [0001] The invention belongs to the technical field of lithium batteries, and in particular relates to a method for preparing lithium hexafluorophosphate. Background technique [0002] Lithium-ion batteries have outstanding advantages such as high working voltage, high energy density, light weight, low self-discharge rate, no memory effect, long cycle life and no pollution, and are widely used in mobile phones, notebook computers, small cameras, electric vehicles, etc. . With the industrialization of electric vehicles, the amount of lithium-ion batteries will also increase. Lithium hexafluorophosphate is an important electrolyte salt of lithium-ion battery electrolyte, and its demand is bound to increase greatly. [0003] There are usually three methods for producing lithium hexafluorophosphate: dry method, wet method and solvent method, and wet method is generally used now. The process is relatively simple, but there are also many problems such as relativ...

AI Technical Summary

Problems solved by technology

The process is relatively simple, but there are also many problems such as relatively low product purity (the purity requirement for electrolytes should reach more than 99.5%), many impurities, and high acidity; there are also many problems such as environmental protection and phosphorus emissions during the production process.