Preparation method of alkali metal difluorophosphate

A technology of difluorophosphoric acid base and hexafluorophosphoric acid base, applied in the direction of phosphorus halide/oxyhalide, etc., can solve problems such as high cost and unsafe process, and achieve the effects of reducing raw material cost, reducing cost and improving process safety.

Pending Publication Date: 2019-03-05
TIANJIN JINNIU POWER SOURCES MATERIAL
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Problems solved by technology

[0008] The purpose of the present invention is to provide a method for the preparation of alkali metal difluorophosphate, to solve the problems of high cost and unsafe process in the prior art, the solid phase reaction method can be adopted, and the non-aqueous solvent reaction method can also be adopted

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  • Preparation method of alkali metal difluorophosphate
  • Preparation method of alkali metal difluorophosphate

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example 1

[0036] Weigh 42.23g of battery-grade lithium hexafluorophosphate and 30.35g of lithium dihydrogen phosphate with a purity of 99.0% under argon environment protection, and add them to a 500ml jacketed three-neck flask, then add 300g of ethylene glycol dimethyl ether with a purity of 99.0%, and the upper part of the flask Connect the serpentine reflux condenser, and then connect the lye absorption device and the drying tower emptying device in sequence. The reaction was stirred at 80° C. for 6 hours, and naturally cooled to room temperature after the reaction. Filtrate under reduced pressure, take the filtrate and rotary evaporate, white crystals are gradually precipitated, and the obtained crystals are gradient vacuum-dried at 80°C to obtain the target product lithium difluorophosphate with a purity of 99.4%.

example 2

[0038]Weigh 33.87g of sodium hexafluorophosphate with a purity of 98.0% and 30.06g of sodium monohydrogen phosphate with a purity of 97.0% under the protection of argon gas and add them to a 200ml volume two-necked stainless steel reaction bottle, and place them on the rollers for mixing after initial mixing Machine mixing for 0.5 hours, so that the reaction raw materials are evenly mixed. React at a temperature of 100°C for 6 hours. During the reaction process, the stainless steel reaction bottle leads to the exhaust pipe, the lye absorption device, and the drying tower emptying device. After the reaction, cool naturally to room temperature, add the reaction solid to 300 g of ethylene glycol dimethyl ether extractant with a purity of 99.0%, stir for 1 hour and filter under reduced pressure, take the filtrate and concentrate it under reduced pressure, and with the volatilization of the extractant, crystals After continuous precipitation, the concentrated crystallization sample...

example 3

[0042] Weigh 35.19g of battery-grade lithium hexafluorophosphate and 25.30g of lithium dihydrogen phosphate with a purity of 99.0% under the protection of argon gas, and put them in a stainless steel reaction bottle connected with an alkali absorption device and a drying tower emptying device, and mix the materials with a roller machine After 0.5 hour, place it at 220° C. for 8 hours to react. Naturally cool to room temperature after the reaction is finished, use 300g of absolute ethanol with a purity of 99.7% as an extractant to dissolve the reaction mixture, stir and extract for 8 hours, so that the target product is extracted completely; then filter under reduced pressure, add an inert solvent after the filtrate is concentrated, and then After a solid-liquid separation operation, the obtained solid was transferred to a vacuum drying device, and dried by a gradient temperature raising method to obtain lithium difluorophosphate with a purity of 99.6%.

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Abstract

The invention relates to a preparation method of alkali metal difluorophosphate. The preparation process is as follows: evenly mixing alkali metal hexafluorophosphate with corresponding dihydrogen phosphate and monohydrogen phosphate, carrying out a reaction, after the solid phase reaction is completed, performing extraction on the reaction mixture by a non-aqueous solvent for a period of time, carrying out filtration to obtain a clarified extract, after a solvent reaction is completed, carrying out filtration, and performing concentration, crystallization and drying on the obtained extract toobtain an alkali metal difluorophosphate solid. The method can also be as follows: uniformly mixing the alkali metal hexafluorophosphate with the corresponding dihydrogen phosphate and monohydrogen phosphate, carrying out a reaction in a non-aqueous solvent, after the reaction is finished, carrying out filtration, and performing concentration, crystallization and drying on the obtained filtrate to obtain the alkali metal difluorophosphate solid. The preparation method of the invention greatly reduces the cost of raw materials, improves the process safety, and has good industrial prospects.

Description

technical field [0001] The invention relates to a method for preparing alkali metal difluorophosphate by reacting alkali metal hexafluorophosphate with corresponding dihydrogen phosphate and monohydrogen phosphate, which is suitable for electrolyte salts or additives in the field of lithium ion batteries. Background technique [0002] In recent years, lithium-ion power batteries have developed rapidly. Under the current lithium-ion battery material system, nickel-cobalt-manganese ternary (Ni x co y mn z ) in the positive electrode material system, adding an appropriate amount of lithium difluorophosphate (LiPO 2 f 2 ) into the electrolyte can reduce the internal resistance of the battery, and form a protective film on the positive electrode of the battery, so that the cycle performance of the battery is significantly improved; in the case of lithium iron phosphate (LiFePO 4 ) In the positive electrode system, lithium difluorophosphate is added as an electrolyte salt int...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/10
CPCC01B25/10C01P2006/80
Inventor 孙培亮赵庆云刘大凡桑俊利袁莉张丽红
Owner TIANJIN JINNIU POWER SOURCES MATERIAL
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