A joint preparation method of lithium difluorophosphate and lithium tetrafluoroborate

A technology of lithium difluorophosphate and lithium tetrafluoroborate, which is applied in tetrafluoroboric acid, chemical instruments and methods, phosphorus compounds, etc., can solve the problems of unstable decomposition and release, large impedance, etc.

Active Publication Date: 2019-09-03
SHANGHAI CHEMSPEC CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But LiPF 6 It is too sensitive to moisture, and the solid electrolyte interfacial film (SEI film) formed at low temperature has too high impedance, and when the temperature rises, it will decompose unstablely and release PF5, which will cause the decomposition of the solvent

Method used

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Examples

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preparation example Construction

[0025] One aspect of the present invention provides a joint preparation method of lithium difluorophosphate and lithium tetrafluoroborate, comprising the following steps: reacting lithium hexafluorophosphate, lithium carbonate, and boron trifluoride in the presence of a reaction solvent to prepare difluoroborate Lithium phosphate and lithium tetrafluoroborate, the reaction equation is as follows:

[0026] LiPF 6 +2Li 2 CO 3 +4BF 3 →LiPO 2 f 2 +4LiBF 4 +2CO 2 ↑.

[0027] In the combined preparation method provided by the present invention, the reaction is usually carried out in the presence of a reaction solvent, which is usually an organic solvent with a certain polarity, so that the reaction substrate has a certain solubility in the solvent, such as , the reaction solvent may be one or more combinations including but not limited to carbonate solvents, carboxylate solvents, nitrile solvents, ketone solvents or ether solvents, etc., more specifically may include but No...

Embodiment 1

[0039] Under nitrogen protection, add 200 g of dimethyl carbonate, Li 2 CO 3 98g, add 100g LiPF dropwise when the temperature rises to 80~85℃ 6 and 500g of dimethyl carbonate, the dropwise addition was completed, and the mixture was kept stirring at 80-85° C. for 6 hours. Through the airway, BF is passed at this temperature 3 Gas, common into BF 3 185g. Continue to insulate and stir at 80-85°C for 2 hours. 19 F NMR to follow the reaction progress, LiPF 6 The integral ratio of F is less than 0.5%, and the reaction ends, and a part of the reaction solvent is started to be distilled under reduced pressure. After steaming 380g dimethyl carbonate, the distillation is stopped. The system was cooled to about 5°C, stirred at this temperature for 1 hour, and filtered to obtain 89.5 g of filter cake and 532 g of filtrate. The filter cake was recrystallized from dimethyl carbonate and dried to obtain LiPO 2 f 2 , weight 65.3g, yield 91.9% (with LiPF 6 ) (detected by ion chroma...

Embodiment 2

[0041] Under nitrogen protection, add 600 g of 2-methyltetrahydrofuran, Li 2 CO 3 98g, heated up to 75-80°C. Add LiPF alternately 6 and BF 3 ·Et 2 O complex (BF 3 ≥46.5%), 10g LiPF each time 6 , 40g BF 3 ·Et 2 O, a total of 10 times were added, and a total of 100g LiPF was added 6 、400g BF 3 ·Et 2 O. During the feeding process, diethyl ether was separated through a thorn-shaped fractionating column to maintain the reaction temperature. After the feeding was completed, the micro-reflux stirring reaction was continued for 9 hours. 19 F NMR to follow the reaction progress, LiPF 6 The integral ratio of F is less than 0.5%, the reaction is over, and a part of the reaction solvent is started to be distilled under reduced pressure. After 250g of 2-tetrahydrofuran is distilled off, the distillation is stopped. The system was cooled to about 5°C, stirred at this temperature for 1 hour, and filtered to obtain 102.6 g of filter cake and 568 g of filtrate. The filter cake ...

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Abstract

The invention relates to the field of chemical synthesis, in particular to a preparation method of two kinds of fluorine-containing lithium salts (lithium difluorophosphate and lithium tetrafluoroborate). The invention provides a combined preparation method of lithium difluorophosphate and lithium tetrafluoroborate. The method comprises the following steps that lithium hexafluorophate, lithium carbonate and boron trifluoride react under the condition of reaction solvent existence; the lithium difluorophosphate and the lithium tetrafluoroborate are obtained through preparation. The novel combined preparation method of the lithium difluorophosphate and the lithium tetrafluoroborate provided by the invention has the advantages that two kinds of high-quality lithium salt products are obtained through one-step reaction and simple separation purification; the reaction solvents are properly recovered and repeatedly recovery can also be realized; three wastes are basically not generated; the environment-friendly effect is achieved; the preparation method is suitable for industrial production.

Description

technical field [0001] The invention relates to the field of chemical synthesis, in particular to two fluorine-containing lithium salts (lithium difluorophosphate (LiPO 2 f 2 ) and lithium tetrafluoroborate (LiBF 4 )), more specifically relates to a joint preparation method of lithium difluorophosphate and lithium tetrafluoroborate. Background technique [0002] Since Lithium-ion batteries were commercialized by Sony in the 1990s, they have been widely used in all aspects of modern production and life because of their advantages such as high working voltage, high energy density, small memory effect, low self-discharge rate, and long cycle life. . [0003] Electrolytes and additives are two important basic raw materials that affect the performance of lithium-ion batteries. Lithium hexafluorophosphate (LiPF 6 ) is currently the preferred electrolyte for lithium-ion battery electrolytes because of its good electrical conductivity, good electrochemical stability, effective ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/455C01B35/06H01M10/0567H01M10/42H01M10/0525
CPCC01B25/455C01B35/066H01M10/0525H01M10/0567H01M10/4235Y02E60/10
Inventor 杨东刘辉何立
Owner SHANGHAI CHEMSPEC CORP
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