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Preparation method of lithium difluorophosphate

A technology of lithium difluorophosphate and lithium hexafluorophosphate, applied in chemical instruments and methods, phosphorus compounds, secondary batteries, etc., can solve problems such as being unsuitable for mass production, long preparation process, and high risk.

Inactive Publication Date: 2021-09-10
DO FLUORIDE CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the prior art, lithium hexafluorophosphate is generally reacted with halides such as lithium chloride and lithium bromide as raw materials, and a small amount of water is added to prepare lithium difluorophosphate. In this method, lithium hexafluorophosphate decomposes to produce hydrogen fluoride gas due to the presence of water, which affects product quality; Or use metaphosphoric acid and hydrogen fluoride to prepare monofluorophosphoric acid, react monofluorophosphoric acid with phosphorus oxyfluoride to obtain difluorophosphoric acid, and then react difluorophosphoric acid with alkali metals to prepare difluorophosphate. long, not suitable for mass production
[0004] Although LiPO 2 f 2 The preparation technology of has been studied by many researchers, but there are still many problems, such as low purity, complicated preparation process, difficult control of the reaction process, harsh reaction conditions and high risk, etc., it is urgent to optimize and improve it to obtain A kind of LiPO with simple preparation process and high product purity 2 f 2 Preparation

Method used

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  • Preparation method of lithium difluorophosphate
  • Preparation method of lithium difluorophosphate
  • Preparation method of lithium difluorophosphate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040]Under a nitrogen atmosphere, high-purity lithium hexafluorophosphate was dissolved in ethylene glycol dimethyl ether solvent at a concentration of 0.1mol / L to obtain solution 1; high-purity lithium difluorooxalate phosphate was dissolved in ethylene glycol dimethyl ether solvent, The concentration is 0.05mol / L to obtain solution 2; the molar ratio of lithium hexafluorophosphate and lithium difluorooxalate borate is 1:4; add solution 2 to solution 1 and react at 80°C for 24 hours; remove insoluble matter by filtration to obtain high-purity difluoro Lithium phosphate solution;

[0041] Concentrate the high-purity lithium difluorophosphate solution to a concentration of 0.8mol / L, induce crystallization by intermittent ultrasonication, ultrasonication for 1min, pause for 1min, and so on continuously alternately; the ultrasonic power is 50W, the ultrasonic frequency is 60KHZ, and the ultrasonic time is 10min; then, Cooling and crystallization by gradient cooling at a cooling ...

Embodiment 2

[0049] Under an argon atmosphere, high-purity lithium hexafluorophosphate was dissolved in ethylene glycol diethyl ether solvent at a concentration of 0.2 mol / L to obtain solution 1; high-purity lithium difluorooxalate phosphate was dissolved in ethylene glycol dimethyl ether solvent, The concentration is 0.1mol / L to obtain solution 2; the molar ratio of lithium hexafluorophosphate and lithium difluorooxalate borate is 1:4; add solution 2 to solution 1 and react at 100°C for 36 hours; remove insoluble matter by filtration to obtain high-purity difluoro Lithium phosphate solution;

[0050] Concentrate the high-purity lithium difluorophosphate solution to a concentration of 1.0 mol / L, and conduct intermittent ultrasonic-induced crystallization, with ultrasonication for 1 minute and pause for 1 minute, and so on continuously alternately; the ultrasonic power is 70W, the ultrasonic frequency is 80KHZ, and the ultrasonic time is 5 minutes; then, Cooling and crystallization by gradi...

Embodiment 3

[0053] Under an argon atmosphere, high-purity lithium hexafluorophosphate was dissolved in ethylene glycol diethyl ether solvent at a concentration of 0.4mol / L to obtain solution 1; high-purity lithium difluorooxalate phosphate was dissolved in ethylene glycol dimethyl ether solvent, The concentration is 0.025mol / L to obtain solution 2; the molar ratio of lithium hexafluorophosphate and lithium difluorooxalate borate is 1:4; add solution 2 to solution 1 and react at 120°C for 48 hours; remove insoluble matter by filtration to obtain high-purity difluoro Lithium phosphate solution;

[0054] Concentrate the high-purity lithium difluorophosphate solution to a concentration of 0.9 mol / L, and conduct intermittent ultrasonic-induced crystallization, with ultrasonication for 1 minute and pause for 1 minute, and so on. The ultrasonic power is 60W, the ultrasonic frequency is 70KHZ, and the ultrasonic time is 8 minutes; then, Cooling and crystallization by gradient cooling at a cooling...

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Abstract

The invention provides a preparation method of lithium difluorophosphate, which comprises the steps of reacting lithium hexafluorophosphate and lithium oxalyldifluoroborate in an organic solvent to obtain a lithium difluorophosphate solution; and filtering, cooling, crystallizing and drying the lithium difluorophosphate solution to obtain the lithium difluorophosphate. According to the preparation method of the lithium difluorophosphate provided by the invention, the reaction process only relates to one-step reaction, so that the process is simple; toxic gases such as fluorine gas and rare resource fluorinating agents such as bismuth fluoride do not need to be adopted in the reaction process, so that the reaction process is low in risk and easy to operate; the reaction is liquid-liquid reaction, and compared with solid-solid / solid-liquid reaction, the reaction is more complete, and the product purity is higher; and no water is introduced into the whole reaction system, so that impurities are prevented from being introduced by hydrolysis of raw materials or products.

Description

technical field [0001] The invention relates to the technical field of lithium difluorophosphate, in particular to a preparation method of lithium difluorophosphate. Background technique [0002] In recent years, under the guidance of national policies, the electric vehicle industry has developed rapidly, and the technical guarantee for the development of electric vehicles lies in the research and development of power batteries, among which lithium-ion power batteries have high hopes for their excellent comprehensive performance. Under the current technical conditions, the high and low temperature cycle performance of lithium-ion batteries directly determines the cruising range and service life of electric vehicles. Lithium difluorophosphate (LiPO 2 f 2 ) as an additive can significantly increase the high-temperature cycle performance of the battery. [0003] With the expansion of the electric vehicle market and the increase in demand for power battery electrolytes, LiPO ...

Claims

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Application Information

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IPC IPC(8): C01B25/455H01M10/0567
CPCC01B25/455H01M10/0567C01P2004/03C01P2006/80C01P2006/82C01P2004/52Y02E60/10
Inventor 薛旭金李洁赵璐云国利云小桂常志强菅玉航张二斌张三成王怀
Owner DO FLUORIDE CHEM CO LTD