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Preparation method of high-purity lithium hexafluorophosphate

A technology of lithium hexafluorophosphate and hexafluorophosphate, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of few production links, many production links, and difficult purification

Active Publication Date: 2013-12-25
CNOOC TIANJIN CHEM RES & DESIGN INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The present invention provides a high-purity lithium hexafluorophosphate preparation method with high safety, low production cost and few production links in order to overcome the disadvantages of high production cost, many production links and difficult purification in the existing process

Method used

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  • Preparation method of high-purity lithium hexafluorophosphate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Take 9.26g of LiF and 60.64g of anhydrous HF to prepare a lithium fluoride solution to form an absorption tank; at the same time, take 60.07g of potassium hexafluorophosphate and place it in a solution composed of 401.21g of hydrogen fluoride and 80.02g of trifluoromethanesulfonic acid In the process, a reaction tank is formed, and the two are connected by a polytetrafluoroethylene hose to form a closed system. After the closed system is formed, the reaction tank is heated, and the heating is slow heating, and the temperature is maintained above 80°C for 8 hours until the weight of the absorption tank does not change. After the reaction is over, lithium hexafluorophosphate is obtained by evaporation and crystallization in the absorption tank. The mass of LiF added is 9.26g, if all of it is converted into LiPF 6 The mass is 54.14g, and LiPF is obtained after drying 6 The mass is 53.67g, so the potassium hexafluorophosphate therein is considered to be completely converte...

Embodiment 2

[0036] Take 18.25g of LiF and 90.3g of anhydrous HF to prepare a lithium fluoride solution to form an absorption tank; at the same time, take 121.5g of potassium hexafluorophosphate and place it in a solution composed of 525g of hydrogen fluoride and 128g of trifluoromethanesulfonic acid. A reaction tank is formed, and the two are connected by a polytetrafluoroethylene hose to form a closed system. Then, the reaction tank is heated slowly, and at the same time, the temperature is maintained above 80°C for 8 hours until the weight of the absorption tank no longer changes. 121.5gKPF added during the test 6 If all decomposed, the available LiPF 6 The mass of 100.4g. After the end of the test, after evaporation and crystallization obtained in the absorption tank, LiPF was obtained. 6 The total mass of is 100.02g, so the potassium hexafluorophosphate therein is considered to be completely converted.

[0037] Table II

[0038] project

Embodiment 3

[0040] After the reaction tank was drained, the weight of the solid wet material was 176.84g, and 100g of acetone was added to remove trifluoromethanesulfonic acid, and the weight of the wet material was 120.32g. According to the complete decomposition of potassium hexafluorophosphate, 60.28g of phosphoric acid was added, and an excess of HF was added. The mass of HF is 321.27g, after stirring for 24 hours, it is filtered, and the resulting solid is sucked dry to obtain 134.24g of white crystals, which are then transferred to a vacuum oven for drying. The drying conditions are: 60°C, vacuum drying for 6 hours, Replace with nitrogen once every half hour, then raise the temperature to 190° C., and after drying for 24 hours, take out the material to obtain 107.2 g of solid material. The above experiments were repeated with the same experimental conditions. It can be seen from the experimental process that if the amount of LiF is assumed to remain unchanged during the KF recycling...

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Abstract

The invention provides a preparation method of high-purity lithium hexafluorophosphate, which is characterized in that the characteristic that PF5 generation is facilitated due to higher solubility of hexafluorophosphate MPF6 in a mixed solvent is utilized. MPF6 is dissolved in the mixed solvent in a reaction tank; MPF6 and anhydrous HF in the mixed solvent react to generate HPF6; HPF6 cannot exist stably under a heating condition, and is decomposed to form PF5; generated PF5 and anhydrous LiF react in an absorption tank to generate LiPF6; a cooling medium is supplied into a reflux condenser tube, so that a part of evaporated anhydrous HF in the reaction tank can be condensed, and MPF6 can be dissolved continuously and converted into HPF6; and finally a high-purity lithium hexafluorophosphate product is obtained by continuous drying under LiPF6 treated inert gas.

Description

technical field [0001] The invention relates to the technical field of manufacturing lithium ion battery materials, in particular to a method for preparing high-purity lithium hexafluorophosphate. More specifically relates to a simple, effective and safe and economical method for preparing PF 5 To produce high-purity lithium hexafluorophosphate. Background technique [0002] Lithium-ion secondary batteries are mainly composed of lithium oxide anodes (such as: LiMnO 4 etc.), carbon negative electrode materials (such as: graphite, etc.) and electrolyte, etc. Among them, the electrolyte solution of the lithium-ion secondary battery mainly contains organic solvents and electrolytes, and the organic solvents that form the electrolyte mainly include dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylene carbonate (EC) and the like. Lithium hexafluorophosphate is the most important electrolyte lithium salt used in lithium-ion secondary batteries due to its good conductivity...

Claims

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Application Information

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IPC IPC(8): C01B25/455
Inventor 刘红光王坤郭西凤叶学海刘大凡安峰袁莉张玥赵洪赵庆云
Owner CNOOC TIANJIN CHEM RES & DESIGN INST
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