A kind of preparation method of porous carbon-coated lithium iron phosphate cathode material

A technology of carbon-coated lithium iron phosphate and positive electrode materials, which is applied in electrode manufacturing, battery electrodes, electrode heat treatment, etc., can solve problems such as unfavorable Li+ movement and obstruction of full contact, so as to reduce ion diffusion resistance and improve low-temperature performance. The effect of increasing the amount of diffusion

Active Publication Date: 2018-03-30
江西智锂科技股份有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the carbon layer formed by the existing carbon coating process is improving the LiFePO 4 The conductivity of the cathode material hinders the LiFePO 4 Full contact with the electrolyte is not conducive to Li + exercise

Method used

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  • A kind of preparation method of porous carbon-coated lithium iron phosphate cathode material
  • A kind of preparation method of porous carbon-coated lithium iron phosphate cathode material
  • A kind of preparation method of porous carbon-coated lithium iron phosphate cathode material

Examples

Experimental program
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Effect test

Embodiment 1

[0026] Weigh 136.2g of absolute ethanol (Tianjin Sunon Chemical Reagent Co., Ltd.) and dissolve it in 136.2g of deionized water, pour it into the reactor; weigh 157g of LiFePO 4 (1mol, 0.2um≤D 50≤1um), 19.4g glucose (0.098mol, because it contains a crystal water, the molecular weight is calculated according to 198, and the corresponding carbon molarity is 0.098*6=0.59mol, Tianjin North Tianyi Chemical Reagent Factory) and 88.2g ammonium carbonate (Tianjin Longyu Chemical Co., Ltd.) After mixing evenly, put it into the reaction kettle, and stir the mixture thoroughly for 1h. The evenly stirred slurry was put into a vacuum freeze dryer (Shanghai Bilang Instrument Co., Ltd.), frozen at -10°C for 1 h, and then dried in a vacuum environment of 13 Pa for 5 h. The dried solid was crushed into small pieces and placed in an oven at 100°C for 1 hour, and then sintered at 750°C for 2 hours under a nitrogen atmosphere. Cool to room temperature, pass through a 325-mesh sieve after grindi...

Embodiment 2

[0029] Weigh 136.2g of absolute ethanol (Tianjin Sunon Chemical Reagent Co., Ltd.) and dissolve it in 136.2g of deionized water, pour it into the reactor; weigh 157g of LiFePO 4 (1mol, 0.2um≤D 50 ≤1um), 19.4g of glucose (0.098mol, Tianjin North Tianyi Chemical Reagent Factory) and 88.2g of ammonium bicarbonate (Tianjin Longyu Chemical Co., Ltd.) were evenly mixed and put into the reaction kettle, and the mixture was fully stirred for 1h. The evenly stirred slurry was put into a vacuum freeze dryer (Shanghai Bilang Instrument Co., Ltd.), frozen at -10°C for 1 h, and then dried in a vacuum environment of 13 Pa for 5 h. After drying, the solid was put into an oven at 100°C, dried for 1 hour, and then sintered at 750°C for 2 hours under a nitrogen atmosphere. Cool to room temperature, pass through a 325-mesh sieve after grinding, and obtain porous carbon-coated LiFePO 4 / C. A button cell was prepared in a glove box (Lab2000 type, manufactured by Etelux Company). Fully charged ...

Embodiment 3

[0031] Weigh 24.7g absolute ethanol (Tianjin Sunon Chemical Reagent Co., Ltd.) and dissolve it in 247.6g deionized, pour into the reaction kettle; weigh 157gLiFePO 4 (1mol, 0.2um≤D 50 ≤1um), 19.4g glucose (0.098mol, Tianjin North Tianyi Chemical Reagent Factory) and 35.3g ammonium bicarbonate (Tianjin Jinhui Taiya Chemical Reagent Co., Ltd.) were mixed evenly and put into the reaction kettle, and the mixture was fully stirred for 1h . The slurry after stirring evenly was placed in a vacuum freeze dryer (Shanghai Bilang Instrument Co., Ltd.), frozen at -10°C for 1h, then dried in a vacuum of 13Pa for 5h, and the dried solid was placed in an oven and heated at 100°C for 1h, nitrogen Sinter at 750°C for 2h in a protective atmosphere. Cool to room temperature, grind and pass through a 325-mesh sieve to obtain the target product.

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Abstract

The invention relates to a preparation method of a porous carbon-coated lithium iron phosphate anode material. The preparation method comprises the following steps: (1) mixing LiFePO4 with a carbon source to obtain a mixture A, and mixing the mixture A with volatile ammonium salt so as to obtain a mixture B; mixing deionized water with absolute ethanol to obtain a solution C; finally, mixing the mixture B with the solution C, so as to prepare slurry; (2) stirring the slurry obtained in the step (1), freezing the slurry at minus 50-minus 10 DEG C for 1-2 hours, drying and grinding at a vacuum state, and heating at 50-120 DEG C for 1-2 hours; and (3) sintering at 400-750 DEG C for 2-4 hours in the presence of nitrogen, and cooling to the room temperature, so as to obtain the porous carbon-coated LiFePO4 / C. By forming holes by virtue of inorganic salt which can be directly decomposed in a gas phase, the preparation method has the special advantages that the process is simple, the cost is low, impurities are not introduced, and the like; and the preparation method is applicable to large-scale industrial production.

Description

technical field [0001] The invention relates to the field of preparation of positive electrode materials for lithium ion batteries, in particular to a method for preparing porous carbon-coated lithium iron phosphate positive electrode materials. Background technique [0002] Lithium iron phosphate (LiFePO 4 ) has become the focus of the development of cathode materials for next-generation lithium-ion batteries due to its abundant raw material reserves, environmental friendliness, good stability, high specific capacity, and good safety performance. However, the low electrical conductivity and the small diffusion coefficient of lithium ions lead to poor rate charge-discharge performance and low-temperature performance, which seriously restrict LiFePO 4 wide application. Therefore, how to improve LiFePO 4 conductivity and Li + Diffusion coefficient is an important target for the improvement of this material. [0003] At present, carbon coating technology is to improve LiFe...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/58H01M4/62H01M4/04H01M10/0525
CPCH01M4/0471H01M4/366H01M4/5825H01M4/625H01M10/0525Y02E60/10
Inventor 梁广川李永胜
Owner 江西智锂科技股份有限公司
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