Synthesis method of lithium hexafluorophosphate

Abstract

The invention discloses a synthesis method of lithium hexafluorophosphate, aiming to provide a lithium hexafluorophosphate synthesis method with low cost, safety and high efficiency. The method comprises the following steps of: firstly, adding dried lithium chloride and potassium hexafluorophosphate to an organic solvent and stirring; secondly, adding a catalyst to the organic solvent; then, heating while stirring at a controlled temperature of 30-80 DEG C for 2-16 h, controlling the temperature to 20-80 DEG C and the heating time of 2-16 h; and finally, filtering insoluble matter to obtain an organic lithium hexafluorophosphate solution. The invention can be applied to the preparation field of the lithium hexafluorophosphate in a lithium ion battery electrolyte.

Description

technical field [0001] The invention relates to a synthesis method of lithium hexafluorophosphate. Background technique [0002] Lithium hexafluorophosphate (LiPF6) relative molecular mass: 190.11, white crystal or powder, relative density 1.50. Strong deliquescence; easily soluble in water, also soluble in low-concentration methanol, ethanol, acetone, carbonates and other organic solvents. Decomposes on exposure to air or heating. When exposed to air or heated, lithium hexafluorophosphate decomposes rapidly in the air due to the action of water vapor, releasing PF5 and producing white smoke. Lithium hexafluorophosphate is mainly used as an electrolyte material for lithium-ion batteries. Lithium hexafluorophosphate electrolyte is mainly used in the manufacture of lithium-ion batteries. [0003] Currently, there are two methods commonly used in the synthesis of lithium hexafluorophosphate (LiPF6): one is to react phosphorus pentachloride (PCl5) and hydrogen fluoride (HF) ...

AI Technical Summary

Problems solved by technology

[0003] Currently, there are two methods commonly used in the synthesis of lithium hexafluorophosphate (LiPF6): one is to react phosphorus pentachloride (PCl5) and hydrogen fluoride (HF) to generate phosphorus pentafluoride (PF5) and hydrogen chloride (HCl), and then use hydrogen fluoride ( HF) is a solvent, and phosphorus pentafluoride (PF5) reacts with LiF to generate lithium hexafluorophosphate (LiPF6), wherein hydrogen fluoride (HF) and hydrogen chloride (HCl) are very corrosive, equipment investment and maintenance costs are high, and a large amount of waste salt is generated in recycling. It is harmful to the environment and prone to safety accidents;

[0004] The other is to generate phosphorus pentafluoride (PF5) by the reaction of phosphorus (P) and fluorine gas (F2), and then use hydrogen fluoride (HF) as a solvent to react phosphorus pentafluoride (PF5) and LiF to generate lithium hexafluorophosphate (LiPF6), Among them, hydrogen fluoride (HF) is very corrosive, and the equipment investment and maintenance costs are high, and a large amount of waste salt is produced after recycling, which is harmful to the environment, and the reaction of phosphorus (P) and fluorine gas (F2) is prone to safety accidents.

[0005] Therefore, the deficiencies in the prior art are: solvents are highly corrosive, equipment investment and maintenance costs are high, environmental hazards are large, and safety accidents are likely to occur