Preparation and purification method of lithium hexafluorophosphate

A technology of lithium hexafluorophosphate and purification method, which is applied in the field of preparation and purification of electrolyte salt lithium hexafluorophosphate, can solve problems such as affecting battery safety, increasing battery internal resistance, reducing moisture content, etc., and achieves the effects of shortening production cycle, reducing moisture and improving efficiency

Active Publication Date: 2017-06-23
东营石大胜华新能源有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] As an important electrolyte salt of lithium ion battery electrolyte, lithium hexafluorophosphate requires high purity (usually not less than 99.5%), and impurities such as water, alkali metals, heavy metals and other impurities such as PCl 3 and POCl 3 The content must be strictly controlled, otherwise it will lead to increased internal resistan

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] A preparation method of lithium hexafluorophosphate, comprising the following steps:

[0048] (1) Preparation of lithium fluoride solution

[0049] Take 1000kg of anhydrous hydrogen fluoride and add it to the synthesis reaction kettle, then add 50kg of high-purity lithium fluoride through an automatic closed feeder, stir well, and control the temperature at around -5°C.

[0050] (2)PF 5 Preparation and purification:

[0051] Add 405kg of phosphorus pentachloride to the stainless steel reactor using a vacuum feeder, and add 195kg of anhydrous hydrogen fluoride into the reactor through an automatic regulating valve. The product is PF 5 , hydrogen chloride, the mixed gas contains a small amount of unreacted hydrogen fluoride, which exists in gaseous form; the mixed gas enters the precision gas filter (filter accuracy 0.1 μm), that is, high-purity PF is prepared 5 Mixed gas with hydrogen chloride.

[0052] (3) After purification, it enters the reaction kettle added wit...

Embodiment 2

[0059] A preparation method of lithium hexafluorophosphate, comprising the following steps:

[0060] (1) Slowly feed fluorine gas and nitrogen gas into the mother liquor after crystallization separation and mix 1kg (F 2 : N 2 =1:4), while stirring, the process lasted for 30 minutes to remove trace moisture in the mother liquor. (F 2 +H 2 O=HF+HFO)

[0061] (2) Return 550kg of all the mother liquors after the removal of impurities in the reactor, then add 500kg of hydrogen fluoride raw material, then add 37kg of lithium fluoride, fully stir, and control the temperature at around -5°C;

[0062] (3) Add 300kg of phosphorus pentachloride to the stainless steel reactor using a vacuum feeder, and add 150kg of anhydrous hydrogen fluoride into the reactor through an automatic regulating valve. MPa, the reaction product is PF 5 , hydrogen chloride, the mixed gas contains a small amount of unreacted hydrogen fluoride, which exists in gaseous form; the mixed gas enters the precisio...

Embodiment 3

[0068] A preparation method of lithium hexafluorophosphate, comprising the following steps:

[0069] (1) Preparation of lithium fluoride solution

[0070] Take 1000kg of anhydrous hydrogen fluoride and add it to the synthesis reaction kettle, then add 50kg of high-purity lithium fluoride through an automatic closed feeder, stir well, and control the temperature at around -5°C.

[0071] (2)PF 5 Preparation and purification:

[0072] Add 405kg of phosphorus pentachloride to the stainless steel reactor using a vacuum feeder, and add 195kg of anhydrous hydrogen fluoride into the reactor through an automatic regulating valve. The temperature of the reaction process is controlled at about 150°C, the pressure is controlled at 0.05MPa, and the reaction product is PF. 5 , hydrogen chloride, the mixed gas contains a small amount of unreacted hydrogen fluoride, which exists in gaseous form; the mixed gas enters the precision gas filter (filter accuracy 0.1 μm), that is, high-purity PF ...

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Abstract

The invention discloses a preparation and purification method of lithium hexafluorophosphate. The method comprises the following steps of (1) preparing a lithium hexafluorophosphate solution by using PF5, LiF and hydrogen fluoride; (2) removing a trace amount of insoluble impurities from the lithium hexafluorophosphate solution obtained in the step (1), transferring the solution o an evaporation crystallizer, and heating and evaporating one part of hydrogen fluoride; and (3) stopping evaporating until the liquid level is 1/3 to 2/3 of initial liquid level, cooling to -20 DEG C to -40 DEG C according to a temperature gradient and filtering to obtain a crude product of lithium hexafluorophosphate and purifying to obtain a target product lithium hexafluorophosphate. The preparation method is simple in process and low in cost, and the obtained product is high in purity.

Description

technical field [0001] The invention belongs to the technical field of power lithium ion battery manufacturing, in particular to a method for preparing and purifying electrolyte salt lithium hexafluorophosphate. Background technique [0002] Lithium-ion batteries have outstanding advantages such as high working voltage, high energy density (light weight), low self-discharge rate, no memory effect, long cycle life and no pollution. It is used in well-known products such as mobile phones, notebook computers, small cameras, and electric vehicles. With the industrialization of electric vehicles, the amount of use is bound to increase. The application shows that lithium-ion battery is an ideal small green power source. Lithium hexafluorophosphate is the key core material for manufacturing lithium-ion batteries, and is the most widely used electrolyte lithium salt in commercial lithium-ion batteries. It has excellent electrochemical properties, good ion conductivity, and good sol...

Claims

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Application Information

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IPC IPC(8): C01D15/00H01M4/58H01M10/0525
CPCC01D15/005C01P2006/80C01P2006/82H01M4/5825H01M10/0525Y02E60/10
Inventor 贾风雷陈效飞吕蕾魏林埔马震袁磊谷洪闪季凯强
Owner 东营石大胜华新能源有限公司
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