Low-temperature synthesis method of high-purity sodium hexafluorophosphate

Abstract

The invention discloses a low-temperature synthesis method of high-purity sodium hexafluorophosphate, which comprises the following steps: dissolving sodium fluoride in an organic solvent solution of Freon to obtain a solution; introducing phosphorus pentafluoride gas into the solution, carrying out low-temperature vacuum reaction for a set time, recovering to normal pressure, and evaporating Freon and the organic solvent to obtain sodium hexafluorophosphate; the reaction temperature of the low-temperature vacuum is-50 to 10 DEG C, and the reaction pressure is-0.2 to 0 MPa. Freon is adopted as a solvent, conditions are mild, the process is simple, and the cost can be effectively reduced; in addition, the Freon liquid can be evaporated by controlling the pressure, and the purity of the sodium hexafluorophosphate can be greatly improved. The reaction process and the subsequent solvent evaporation process are both carried out at low temperature, so that the decomposition of sodium hexafluorophosphate at high temperature can be effectively avoided, and the yield is improved.

Description

technical field [0001] The invention belongs to the technical field of batteries, and in particular relates to a low-temperature synthesis method of high-purity sodium hexafluorophosphate. Background technique [0002] The statements herein merely provide background related to the present invention and do not necessarily constitute prior art. [0003] New energy vehicles and large-scale energy storage are in urgent need of secondary batteries with high energy density and high safety. Na-ion batteries have promising application prospects in the field of energy storage due to their potential cost advantages. Sodium hexafluorophosphate is an important electrolyte salt in the electrolyte of sodium ion battery, which requires high purity. If the impurity content is too high, the internal resistance of the battery will increase, the capacity will decay rapidly, the cycle life will be reduced, and even the safety of the battery will be affected. However, the inventor found that ...

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Problems solved by technology

Excessive impurity content in it will increase the internal resistance of the battery, rapidly decay the capacity, reduce the cycle life, and even affect the safety of the battery

But the contriver finds, the purity of sodium hexafluorophosphate product in the prior art is on the low side, can't meet the requirement of the further development of sodium ion battery