Preparation method of positive electrode material LiFePO4/C of lithium ion battery

A lithium-ion battery, cathode material technology, applied in battery electrodes, circuits, electrical components, etc., can solve the problems of high rate discharge and low temperature performance, coarse particles, coarse product particles and other problems, to achieve excellent electrochemical performance, control and Easy operation and uniform particle size distribution

Inactive Publication Date: 2011-01-19
XINJIANG JINSHENGDA NONFERROUS METAL MATERIALS CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, LiFePO 4 There are also two major defects: one is low electrical conductivity, and the other is low ion diffusion coefficient, resulting in poor high-rate discharge and low-temperature performance of the material
Although this method is easy to synthesize LiFePO 4 /C, but there are also large defects: if the sintering temperature is low, LiFePO 4 The crystallinity is not high, which affects the electrochemical performance of the material; if the reaction and sintering temperature is to be increased, the product particles will be coarse and the particle size distribution will be uneven; and amorphous carbon often cannot be

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Lithium carbonate, ferrous oxalate and ammonium dihydrogen phosphate are uniformly mixed according to the molar ratio of Li:Fe:P element 1.02:1:1, and then 334.9kg of the resulting mixture and 10kg of polystyrene balls with a particle size of 1000nm are put into the ball In the tank (zirconia balls, the ball-to-material ratio is 3:1); then add 300kg of deionized water to ball mill for 4 hours, and dry the ball-milled slurry in an oven at 60°C to make a precursor powder.

[0021] In a nitrogen protective atmosphere, first raise the temperature to 350°C and keep it for 3h, then raise the temperature to 550°C and keep it for 8h. In-situ synthesis of LiFePO with a particle size of 200-300nm and a coating carbon content of 1.9% by solid-state reaction 4 / C cathode material.

Embodiment 2

[0023] Lithium carbonate, iron oxide and ammonium dihydrogen phosphate are evenly mixed according to the molar ratio of Li:Fe:P element 1.03:1.01:1, and then 233.9kg of the resulting mixture and 10kg of polystyrene balls with a particle size of 150nm are put into a spherical tank medium (zirconia balls, the ball-to-material ratio is 3:1); then 300 kg of deionized water was added for ball milling for 4 hours, and the ball-milled slurry was dried in an oven at 60° C. to make a precursor powder.

[0024] In a nitrogen protective atmosphere, first raise the temperature to 350°C and keep it for 3h, then raise the temperature to 600°C and keep it for 8h. In-situ synthesis of LiFePO with a particle size of 200-300nm and a coating carbon content of 1.5% by solid-state reaction 4 / C cathode material.

Embodiment 3

[0026] Lithium hydroxide, ferrous oxalate and ammonium dihydrogen phosphate are evenly mixed according to the molar ratio of Li:Fe:P element 1.05:1.02:1, and then 342.8kg of the resulting mixture and 30kg of polystyrene balls with a particle size of 150nm are put into the In a spherical tank (zirconia balls, the ball-to-material ratio is 3:1); then add 600kg of deionized water and ethanol (volume ratio 1:1) for ball milling for 4 hours, and the ball-milled slurry is spray-dried at 200°C Make precursor powder.

[0027] In an argon protective atmosphere, first raise the temperature to 350°C and keep it for 3h, then raise the temperature to 650°C and keep it for 8h. In-situ synthesis of LiFePO with a particle size of 250-400nm and a coating carbon content of 3.2% by solid-state reaction 4 / C cathode material.

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Abstract

The invention discloses a method for preparing the positive electrode material LiFePO4/C of a lithium ion battery by adopting carbon sources of the polystyrene sphere series. A carbon thermal reduction and solid phase sintering method is adopted in the preparation process. The method comprises the following concrete steps: firstly, uniformly mixing a lithium source, an iron source and a phosphorus source, and then, mixing the mixture with a carbon source; then, adding a solvent for ball milling, and drying to obtain a precursor; and pretreating and calcining the precursor in the protective atmosphere, and then, cooling the precursor in a furnace to synthesize the LiFePO4/C of which the particle size distribution is uniform and the particle diameter is 200-500nm. The invention has the advantages of wide sources of raw materials, simple preparation method, convenient control and operation, good carbon coating effect, excellent electrochemical performance and the like.

Description

technical field [0001] The present invention relates to the preparation method of lithium-ion battery cathode material, especially the lithium-ion battery cathode material LiFePO 4 / C preparation method. Background technique [0002] Cathode materials are an important part of lithium-ion batteries, and the development of new cathode materials has become one of the keys to the development of lithium-ion batteries. Olivine structure LiFePO 4 It has the advantages of low cost, environmental friendliness, high capacity, good safety performance, stable cycle, and stable discharge voltage. However, LiFePO 4 There are also two major defects: one is low electrical conductivity, and the other is low ion diffusion coefficient, which leads to poor high-rate discharge and low-temperature performance of the material. To overcome this shortcoming, technologies such as carbon coating, particle size reduction and ion doping are often used to improve. [0003] Currently, LiFePO 4 The m...

Claims

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Application Information

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IPC IPC(8): H01M4/139
CPCY02E60/122Y02E60/10
Inventor 涂江平周云叶向果关勇辉张文魁穆鑫封国富马育新方智三刘葵郁
Owner XINJIANG JINSHENGDA NONFERROUS METAL MATERIALS CO LTD
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