Method for preparing lithium hexafluorophosphate from organic solvent

Abstract

The invention discloses a method for preparing lithium hexafluorophosphate from an organic solvent. The method comprises the following steps: I, dissolving lithium fluoride into solvents such as triethylamine to obtain a solution A; II, filtering the solution A to obtain filtrate B, adding excessive phosphorus pentafluoride into the filtrate B; III, directly precipitating out a lithium hexafluorophosphate product, and filtering, cleaning and drying to obtain a product. Compared with a conventional organic solvent method, the method does not need use a surfactant, can truly dissolve lithium fluoride, and can effectively remove other impurities in lithium fluoride through filtration, and therefore, crude lithium fluoride can be adopted, and low-cost purifying can be realized. Meanwhile, a non-polar solvent is used for better stabilizing phosphorus pentafluoride, so that side reaction is not liable to occur.

Description

technical field [0001] The invention relates to the field of lithium hexafluorophosphate synthesis, in particular to a method for preparing lithium hexafluorophosphate with an organic solvent. Background technique [0002] In recent years, our country has vigorously developed new energy vehicles to achieve energy saving, emission reduction and pollution reduction. This policy has brought about a huge demand for power lithium-ion batteries and has led to insufficient supply of lithium hexafluorophosphate. The synthesis of lithium hexafluorophosphate has high technical difficulty. At present, some enterprises in my country have mastered the synthesis method of lithium hexafluorophosphate, and realized the domestic independent supply of lithium hexafluorophosphate. [0003] LiPF used in lithium battery electrolyte 6 Due to the unstable characteristics of heat and water, it is possible to prepare high-purity LiPF 6 The difficulty is higher. The current industrial production...

AI Technical Summary

Problems solved by technology

This policy has brought about a huge demand for power lithium-ion batteries and has led to insufficient supply of lithium hexafluorophosphate

The synthesis of lithium hexafluorophosphate has high technical difficulty

[0006] There are also some shortcomings in the existing organic solvent method: at first, the polar and weak polar solvents used react easily with phosphorus pentafluoride, producing impurities and consuming organic solvents; secondly, because the organic solvents used cannot dissolve fluorine Lithium chloride, so that the synthesis process is a liquid-solid two-phase reaction, the reaction speed is relatively slow, and the reaction is not complete; again, the obtained lithium hexafluorophosphate product is dissolved in an organic solvent, and the workload of evaporation and concentration is large, and lithium hexafluorophosphate is highly unstable, and it needs to be heated for a long time It will cause its decomposition and reduce the purity of the product; then, the traditional organic solvent method has higher requirements on the purity of lithium fluoride, which requires complex lithium fluoride purification, and the synthesis cost is higher; finally, because lithium fluoride cannot be dissolved in traditional solvents Among the solvents of the method, the impurity of lithium fluoride exists in the product, which increases the purification cost of lithium hexafluorophosphate

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