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A kind of method for preparing lithium difluorophosphate

A technology of lithium difluorophosphate and boric acid, which is applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of difficult purification, high requirements for reaction conditions, and many by-products, so as to improve cycle stability and reaction The effect of mild conditions and good interfacial compatibility

Active Publication Date: 2020-09-15
SHANGHAI ROLECHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, published patent WO2012004187A2 proposes a method for producing lithium difluorophosphate, wherein LiHPO 4 Gas-solid reaction occurs with HF at 140°C to form a mixture of lithium difluorophosphate, lithium monofluorophosphate and lithium fluoride, which is difficult to separate; published patent WO2012004188A1 proposes another method for producing lithium difluorophosphate, wherein P 2 o 5 A solid-solid reaction occurs with LiF at 300°C to form a solid solution mixture of lithium difluorophosphate and lithium phosphate. A small amount of lithium difluorophosphate can only be separated after grinding and extraction for a long time; Japanese Patent Laid-Open 2014- 62036 uses LiPF 6 Lithium difluorophosphate is obtained by mixing with LiCl and then passing water vapor. Although this method has cheap raw materials, the reaction is not easy to control, and there are many by-products, which are difficult to purify and are not suitable for large-scale production.
Japanese Patent Special Table 2013-534511 adopts P 4 o 10 The powder reacts with LiF powder. Due to the solid-solid reaction, the resulting mixture is extracted with an organic solvent. This method has high requirements on the reaction conditions, which is not conducive to safe production, energy saving and emission reduction, and the yield is low, the operation is complicated, and it is easy to form by-product
[0004] It can be seen from the above that there are various defects in the existing preparation method, or the process is complicated, the cost is high, it is difficult to industrialize production, or the yield is low, there are many by-products, it is not easy to purify, and the prepared difluorophosphate has low purity, which affects the product performance.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] Embodiment 1 provides the method for preparing lithium difluorophosphate, comprises the following steps:

[0048] At room temperature, add 69.6g (1.0mol) of diboron trioxide into 720g of anhydrous acetonitrile, slowly add 239.3g (1.575mol) of lithium hexafluorophosphate solid with a solid feeder under stirring, then raise the temperature to 70°C for 5 hours, Lower the temperature to normal temperature to filter out a small amount of insoluble matter, then concentrate the filtrate under normal pressure until it is thicker with stirring, add 720g of dry 1,2-dichloroethane, and then slowly cool the system to 20°C, the product gradually turns white and fine Precipitate in the form of granular solids, filter the mother liquor, and wash the product with 240g of dry acetonitrile and 1,2-dichloroethane mixed solvent (mass ratio: 1:4), and dry the obtained product in vacuum at 60°C for 5 hours, 152.0 g of white powder lithium difluorophosphate was obtained, the molar yield was 9...

Embodiment 2

[0050] Embodiment 2 provides the method for preparing lithium difluorophosphate, comprises the steps:

[0051] At normal temperature, 24.85g (0.5mol) of lithium metaborate and 76.0g (0.5mol) of lithium hexafluorophosphate were added to 380g of dry tetrahydrofuran, the temperature was raised to reflux for 5 hours under stirring, and a small amount of insoluble matter was filtered off at normal temperature. Concentrate the filtrate under normal pressure until it is relatively viscous when stirring, add 380g of dry dichloromethane, then slowly cool the system to 20°C, the product gradually precipitates in the form of white fine particle solids, filter the mother liquor, and use 76g of dry tetrahydrofuran Wash the product with a mixed solvent of dichloromethane (mass ratio is 1:4), and dry the resulting product in vacuum at 60°C for 5 hours to obtain 47.3g of white powdery lithium difluorophosphate, with a molar yield of 87.7%. Chromatographically determined purity was 99.0%.

Embodiment 3

[0053] Embodiment 3 provides the method for preparing lithium difluorophosphate, comprises the steps:

[0054] At room temperature, 84.6g (0.5mol) of anhydrous Li 2 B 4 o 7 Add 265.8g (1.75mol) of lithium hexafluorophosphate to 797g of dry ethylene glycol dimethyl ether, heat up to 60°C under stirring and react for 6 hours, drop to normal temperature and filter out a small amount of insoluble matter, and concentrate the filtrate under normal pressure until it is relatively viscous when stirred 797g of dry toluene was added, then the system was slowly cooled to 20°C, the product gradually precipitated, the mother liquor was filtered off, and the product was washed with 266g of dry ethylene glycol dimethyl ether and toluene mixed solvent (mass ratio: 1:4), The obtained product was vacuum-dried at 60° C. for 5 hours to obtain 166.3 g of white powdery lithium difluorophosphate, the molar yield was 88.1%, and the purity determined by ion chromatography was 99.5%.

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PUM

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Abstract

The invention relates to the field of lithium battery electrolyte additives and in particular to an economic preparation method suitable for industrially producing lithium difluorophosphate. The method at least comprises the following steps: (1), enabling an oxidized boron compound to react with lithium hexafluorophosphate, to obtain a lithium difluorophosphate mixture; and (2), concentrating thelithium difluorophosphate mixture, adding a poor solvent, crystallizing, and separating to obtain the lithium difluorophosphate.

Description

technical field [0001] The invention relates to the field of lithium battery electrolyte additives, in particular to an economical preparation method of lithium difluorophosphate suitable for industrial production. Background technique [0002] With the technological development and commercialization of lithium-ion batteries, lithium-ion batteries are widely used in consumer electronics, power products, and energy storage products. In the next few years, lithium-ion batteries will become an expanding global industry. At the same time, with the expansion of its application field, the demand for further improvement of battery characteristics is also increasing. As a conductive salt, lithium difluorophosphate can form a film on the electrode interface to improve high and low temperature cycle performance and effectively reduce the amount of lithium hexafluorophosphate used in batteries and batteries. Therefore, in the context of the continuous expansion of the market size of ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/455
CPCC01B25/455
Inventor 刘俊张东全
Owner SHANGHAI ROLECHEM CO LTD
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