Carbonate-assisted preparation method for lithium iron phosphate

A carbonate and lithium source technology, applied in the field of hydrothermal preparation of lithium iron phosphate cathode materials, can solve the problems of poor high rate performance, poor consistency, poor cycle performance, etc., to improve cycle stability, batch Good stability and improved cycle performance

Active Publication Date: 2014-12-03
ZHANGJIAGANG HUASHENG CHEM CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a method for preparing lithium iron phosphate, a cathode material for lithium ion batteries, which overcomes the low yield, poor consistency, poor high-rate performance and cycle performance of the current hydrothermal method for preparing lithium iron phosphate materials poor disadvantage

Method used

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  • Carbonate-assisted preparation method for lithium iron phosphate
  • Carbonate-assisted preparation method for lithium iron phosphate
  • Carbonate-assisted preparation method for lithium iron phosphate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Take LiOH·H 2 O, H 3 PO 4 , FeSO 4 ·7H 2 O is the basic raw material, and according to the molar ratio Li:Fe:P=3.0~3.05:1:1~1.05, it is made into an aqueous solution and mixed and stirred evenly. The concentration of the reactant is 0.5mol / L in terms of lithium ion concentration. 2 SO 4 Adjust the pH value of the reactant to 8. In order to prevent the ferrous iron from being oxidized, the whole stirring process is carried out under the protection of Ar, and then the volume ratio is 50% ethylene carbonate (EC) and the above solution are fully mixed and stirred for 30 minutes, and then quickly moved into 500ml React at 180°C for 600 minutes in a hydrothermal reactor.

[0041] After the above reaction is completed, the resulting precipitate is washed with deionized water and ethanol until the pH of the solution is neutral, and the obtained precipitate is dried under vacuum at 100°C for 5 hours to obtain off-white LiFePO 4 powder. The above gray-white LiFePO 4 After...

Embodiment 2

[0043] Take LiOH·H 2 O, H 3 PO 4 , FeCl 2 As the basic raw material, according to the molar ratio of Li:Fe:P=3.0~3.05:1:1~1.05, it is made into an aqueous solution and mixed and stirred evenly. The concentration of the reactant is 1mol / L in terms of lithium ion concentration, and the pH of the reactant is adjusted by HCl The value is 10. In order to prevent the ferrous iron from being oxidized, Ar protective gas is introduced during the whole stirring process, and then the volume ratio is 20% propylene carbonate (PC) and the above solution are fully mixed and stirred for 30 minutes, and then quickly moved into 500ml of hydrothermal The reaction was carried out at 180° C. for 600 minutes in the reaction kettle.

[0044] After the above reaction is completed, the precipitate is washed with a mixture of deionized water and ethanol until the pH of the solution is neutral, and the obtained precipitate is vacuum-dried at 120°C for 5 hours to obtain off-white LiFePO 4 powder. Th...

Embodiment 3

[0046] With Li 2 CO 3 、H 3 PO 4 、Fe(Ac) 2 ) 2 As the basic raw material, according to the molar ratio of Li:Fe:P=3.0~3.05:1:1~1.05, it is made into an aqueous solution and mixed and stirred evenly. The concentration of the reactant is 0.5mol / L in terms of lithium ion concentration. 3 PO 4 Regulate reactant pH value to be 9, in order to prevent ferrous iron from being oxidized, pass into Ar protective gas during the whole stirring process, be that 50% diethyl carbonate (DEC) is mixed with above-mentioned solution fully then and stir quickly after 30 minutes by volume ratio Transfer to a 500ml hydrothermal reactor and react at 200°C for 600 minutes.

[0047] After the above reaction is completed, the product is washed with deionized water and ethanol until the pH of the solution is neutral, and the obtained precipitate is vacuum-dried at 120°C for 5 hours to obtain off-white LiFePO 4 powder. The above gray-white LiFePO 4 The powder product and ascorbic acid are fully mi...

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Abstract

A method for preparing a lithium-ion battery positive electrode material with the assistance of carbonic ester comprises: using a lithium source compound, a phosphorus source compound, an iron source compound at a molar ratio of Li：Fe：P=3.0-3.05：1：1-1.05 to form a mixed water solution; adding organic carbonic ester into the mixed water solution, and controlling a volume ratio between the organic carbonic ester and the water at 1: 1-10, a pH value at 6.0-12.0 and a lithium-ion concentration at 0.5-2mol / L, and stirring the mixed water solution under an inert protective atmosphere; performing reaction in a sealed contained for 5 to 24 hours at a temperature of 140 to 240 degrees centigrade; deionizing a reaction product and performing full washing, and performing drying, mixing the product with a carbonaceous organic material according to a mass ratio of 100: 1-20, performing tablet compressing, and performing thermal treatment under the protective atmosphere; and performing cooling, grinding and sieving to obtain a carbon-coated lithium iron phosphate positive electrode material. The particle size of the product prepared by using the method is uniform (100-400nm), the yield exceeds 98%, the phase purity exceeds 99.6%, electrochemical performance is outstanding, batch stability is good, and rate charging-discharging performance is greatly improved.

Description

technical field [0001] The invention provides a hydrothermal preparation method of a high-purity, high-yield and high-performance lithium iron phosphate positive electrode material, specifically, on the basis of the hydrothermal method, an organic carbonate solvent is used to assist the growth of a nanometer iron phosphate positive electrode material, especially The electrochemical performance of lithium iron phosphate was improved by adding different types and amounts of carbonates. Background technique [0002] Lithium iron phosphate, as the positive electrode material of a new generation of lithium-ion secondary batteries, has many advantages such as high open circuit voltage, high energy density, long cycle life, environmental friendliness, and high safety performance, making it a hot spot in the research of power and energy storage batteries. Energy storage batteries have higher and higher requirements for high-current charge-discharge performance and long-term cycle li...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58
CPCH01M4/1397H01M4/582H01M4/625H01M10/0525Y02E60/10
Inventor 郑洪河李靖张力沈鸣
Owner ZHANGJIAGANG HUASHENG CHEM CO LTD
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