Method for preparing lithium hexafluorophosphate quickly

Abstract

The invention discloses a method for preparing lithium hexafluorophosphate quickly. The method comprises steps as follows: (1) performing distillation to obtain a hydrogen fluoride liquid with the purity higher than 99.99wt%; (2) reacting the hydrogen fluoride liquid with phosphorous pentachloride to obtain a mixed gas of phosphorus pentafluoride and hydrogen chloride; (3) feeding the mixed gas of the phosphorus pentafluoride and the hydrogen chloride into hydrogen fluoride and lithium fluoride to obtain a lithium hexafluorophosphate solution; (4) filtering the lithium hexafluorophosphate solution obtained in Step (3) to remove insoluble impurities, performing stirring crystallization on a filtrate at the stirring speed of 50-100 rpm, and performing rotary drying at the temperature of 120 DEG C-130 DEG C after stirring crystallization to directly obtain the lithium hexafluorophosphate product with the radius ranging from 100 meshes to 400 meshes. According to the method, the operation is convenient, the lithium hexafluorophosphate obtained through stirring crystallization is in uniform granule shape directly, repeated drying and crushing steps are omitted, and the crystallization time is shortened.

Description

technical field [0001] The invention relates to a method for rapidly 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. In recent years, it has quickly occupied many fields with its incomparable advantages over other batteries, and is widely used in well-known mobile phones, notebook computers, small cameras, electric vehicles and other products. With the industrialization of electric vehicles, the amount of lithium-ion batteries is bound to increase. The application shows that lithium-ion battery is an ideal small green power source. [0003] Lithium hexafluorophosphate is an important electrolyte salt of lithium-ion battery electrolyte, which requires high purity (usually not less than 99.5%), and impurities such as water, alkali metals, heavy metals and other imp...

AI Technical Summary

Problems solved by technology

[0003] As an important electrolyte salt of lithium ion battery electrolyte, lithium hexafluorophosphate requires high purity (usually not less than 99.5%), and impurities such as water, alkali metals, heavy metals and other impurities such as PCl 3 and POCl 3 The content must be strictly controlled, otherwise it will lead to increased internal resistance of the battery, rapid decay of battery capacity, shortened cycle life, and even affect the safety of the battery

[0006] (1), the first-level drying in step 4 is standing and drying, and the crystallization time generally takes about 48 hours, and it is easy to agglomerate. After crystallization, the lithium hexafluorophosphate product forms a larger crystal block as a whole, and it is difficult to remove from the crystallization tank. It is difficult to peel off and crush in the middle. After the primary drying, the lithium hexafluorophosphate product needs to be crushed according to the particle size requirements, which is time-consuming and laborious;

[0007] (2) Only a small amount of reaction raw materials can be processed each time, which cannot meet the production needs of large quantities

[0008] (3) It needs to go through two drying treatments, which takes a long time and is time-consuming and labor-intensive