Preparation method of high-purity lithium tetrafluoroborate

A technology of lithium tetrafluoroborate and high-purity lithium fluoride, which is applied in the directions of tetrafluoroboric acid, borate, boron oxide, etc., can solve the difficulty of increasing the production control process, the low yield of lithium tetrafluoroborate, and the acidic substances in the product. Exceeding the standard and other problems, to achieve the effect of convenient transportation and storage, abundant source of raw materials, and reducing the viscosity of the system

Active Publication Date: 2012-12-19
GUANGZHOU TINCI MATERIALS TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The above method uses gaseous BF3 to enter the system to participate in the reaction, which involves the preparation and transportation of BF3 gas, which increases the corrosion resistance requirements of the equipment and the complexity of system design; BF3 can undergo complexation reactions with almost all the above-mentioned organic solvents, and the heat of reaction Larger, which increases the difficulty of production control process; the reaction ends with the clarification of the LiF complete reaction solution, and BF3 is easily added in excess. If the complex formed by excess BF3 and organic solvent is not completely removed, the acidic substance of the product will exceed the standard and affect the use. performance
[0008] Other LiBF4 synthetic methods also have the method that Chinese patent CN101648963A discloses and obtain lithium tetrafluoroborate and lithium difluorooxalate borate simultaneously, and this method lithium tetrafluoroborate productive rate is lower

Method used

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  • Preparation method of high-purity lithium tetrafluoroborate
  • Preparation method of high-purity lithium tetrafluoroborate
  • Preparation method of high-purity lithium tetrafluoroborate

Examples

Experimental program
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Effect test

Embodiment 1

[0048] The molar ratio of high-purity lithium fluoride to boron trifluoride complex is 1.1, the reaction temperature is 8°C, and the reaction time is 23h;

[0049] After the reaction is completed, unreacted lithium fluoride is removed by filtration, and the filtrate is heated and concentrated under vacuum or under the protection of a dry inert gas until the LiBF4 content in the concentrate is 70%;

[0050] Add a low-polarity solvent to the concentrate, extract the remaining chain carbonate organic solvent, and promote the precipitation of lithium tetrafluoroborate in the system;

[0051] After extraction and crystallization, filter, and then wash with an organic solvent to remove the residual linear carbonate solvent. The organic solvent for washing can be cyclohexane, cyclopentane, hexane, pentane, carbon tetrachloride, diethyl ether, propyl ether, butyl ether One or more mixtures of , toluene, xylene or styrene, the wet product obtained after washing is dried under the prote...

Embodiment 2

[0053] Same as Example 1, except that the molar ratio of high-purity lithium fluoride to boron trifluoride complex is 1.2, the reaction temperature is 35° C., and the reaction time is 15 h;

[0054] After the reaction is completed, unreacted lithium fluoride is removed by filtration, and the filtrate is heated and concentrated under vacuum or under the protection of a dry inert gas until the LiBF4 content in the concentrate is 65%.

Embodiment 3

[0056] Same as Example 1, except that the molar ratio of high-purity lithium fluoride to boron trifluoride complex is 1.4, the reaction temperature is 12°C, and the reaction time is 5h;

[0057] After the reaction is completed, unreacted lithium fluoride is removed by filtration, and the filtrate is heated and concentrated under vacuum or under the protection of a dry inert gas until the LiBF4 content in the concentrate is 45%.

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Abstract

The invention provides a preparation method of high-purity lithium tetrafluoroborate; and the method comprises the following steps that high-purity lithium fluoride and a boron trifluoride coordination compound react in chain carbonate organic solvent, and lithium tetrafluoroborate is obtained after filtration, concentration, extractive crystallization, washing and drying. In the preparation method of high-purity lithium tetrafluoroborate, the boron trifluoride coordination compound has wide sources of raw materials and is low in price, the linear carbonate organic solvent has low toxin and is environment-friendly, the synthetic reaction conditions are mild, the operation is simple, the equipment investment is low, the lithium tetrafluoroborate productivity is high, the yield is high, the energy consumption is low, the post-treatment is simple, and the method is applicable to large-scale production.

Description

technical field [0001] The invention relates to the technical field of preparation of electrolyte salts used in lithium ion batteries, in particular to a preparation method of high-purity lithium tetrafluoroborate. Background technique [0002] The chain and cyclic carbonate solution of LiPF6 is the most typical electrolyte system for commercial lithium-ion batteries at present. The system has high conductivity and can form a stable SEI film to protect the electrode. However, LiPF6 is sensitive to moisture, unstable to heat, and decomposes. The generated PF5 and HF will cause continuous damage to various materials in the battery, resulting in a continuous decline in battery performance. Compared with LiPF6, LiBF4 has the advantages of insensitivity to environmental moisture, strong thermal stability, effective prevention of common Al current collector corrosion, and good low-temperature performance, so it has been widely used in electrolyte formulations that require better l...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B35/12
CPCC01B35/066
Inventor 陈晓军张若昕徐金富孙伏恩陈春才胡咬初
Owner GUANGZHOU TINCI MATERIALS TECH
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