Hydrothermal synthesis method of LiFePO4 of anode material of lithium ion battery with one-dimensional nanometer structure

A technology of lithium-ion batteries and hydrothermal synthesis, which is applied to battery electrodes, phosphorus compounds, structural parts, etc., can solve the problems of poor product rate performance, difficult wastewater treatment, difficult to control particle size, etc., to prolong cycle life and reduce equipment investment The effect of small size and increased compaction density

Inactive Publication Date: 2010-06-23
HEBEI UNIV OF TECH
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved by the present invention is to provide a hydrothermally synthesized lithium-ion battery for the problems existing in the current technology that the crystal morphology and particle size are difficult to control, the rate performance of the product is poor, and the wastewater containing surfactants is difficult to treat. Method for cathode material lithium iron phosphate

Method used

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  • Hydrothermal synthesis method of LiFePO4 of anode material of lithium ion battery with one-dimensional nanometer structure
  • Hydrothermal synthesis method of LiFePO4 of anode material of lithium ion battery with one-dimensional nanometer structure
  • Hydrothermal synthesis method of LiFePO4 of anode material of lithium ion battery with one-dimensional nanometer structure

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Experimental program
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Effect test

Embodiment 1

[0029] The first step, hydrothermal synthesis reaction (Li:Fe:P=3:1:1.03)

[0030] Will contain 223.4g Fe 2+ (that is, 4mol) of pure ferrous sulfate solution that is nearly saturated is diluted to 3.5L (the pH value of this solution is about 0.5); 475.0g of 85% phosphoric acid containing 4.12mol of pure phosphoric acid is diluted to 1L; 503.3g of 12mol of LiOH·H 2 O was dissolved in water and diluted to 3L.

[0031] Add above-mentioned phosphoric acid solution and lithium hydroxide solution in the autoclave of 10L band sealing feeding pipe and cooling coil, after purging the air in the dead volume in the still with inert gas (nitrogen), seal autoclave, under the stirring of rotating speed 200rpm from Heat at room temperature to 40°C, open the feed valve and exhaust valve, and add the ferrous sulfate solution prepared above under stirring at a feed rate of 300ml / min for 11.6 minutes. Seal the autoclave, after stirring for 20 minutes, open the feed valve and exhaust valve, th...

Embodiment 2

[0056] Change the amount of lithium hydroxide as the pH regulator in Example 1 to 8g, and the initial pH of the reaction system is 6.5, and the others are the same as in Example 1.

[0057] After the synthesis is completed, filter and wash to obtain 1080 g of filter cake and 7.4 L of mother liquor. The filter cake was vacuum-dried at 120°C for 12 hours to obtain 617g LiFePO 4 Off-white powder.

[0058] The particle shape of the product is a hexagonal sheet with indistinct edges and corners, the thickness of the sheet is about 100 nanometers, and there is basically no agglomeration between the particles. The electrochemical performance test results and particle size analysis results are shown in Table 1.

Embodiment 3

[0060] Change the amount of lithium hydroxide as the pH regulator in Example 1 to 22g, and the initial pH of the reaction system is 8.0, and the others are the same as in Example 1.

[0061] After the synthesis is completed, filter and wash to obtain 1091g filter cake and 7.4L mother liquor. The filter cake was vacuum-dried at 120°C for 12 hours to obtain 619g LiFePO 4Off-white powder.

[0062] The particle morphology of the product is a hexagonal sheet with indistinct edges and corners, the thickness of the sheet is about 90 nanometers, and there is a small degree of agglomeration between the particles. The electrochemical performance test results and particle size analysis results are shown in Table 1.

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Abstract

The invention discloses a hydrothermal synthesis method of LiFePO4 of anode material of lithium ion battery with one-dimensional nanometer structure, which comprises the steps of: 1. respectively adding lithium hydroxide solution and phosphoric acid, evenly adding iron source solution with a certain speed, wherein the molar ratio of the proportion of the added materials Li: Fe: P is 3.0:1.0:1.0-1.15, stirring 10-30 for minutes, adding pH value adjusting agent, leading the initial pH value of a reaction system to be 6.5-8.0, and reacting for 60-480 minutes at 40-180 DEG C; 2. filtering, washing and drying resultant; and 3. packing carbon. The hydrothermal synthesis method can take raw material solution for generating ferrous sulfate as iron source, produces a product with good performance by adjusting the pH value of the reaction system and controlling the feeding speed, eliminates working procedures for crystallizing and drying the ferrous sulfate and the like, is good for reducing water electricity consumption, and has less equipment investment, simple and controllable technology and good batch stability of the product.

Description

technical field [0001] The invention belongs to the preparation of positive electrode materials of lithium ion batteries, in particular to a hydrothermal synthesis method of lithium iron phosphate, a positive electrode material of lithium ion batteries with a one-dimensional nanostructure. technical background [0002] Lithium iron phosphate has been reported as a cathode material for lithium-ion batteries for more than ten years, and has attracted great attention because of its safety, low cost, and environmental friendliness. In recent years, due to the gradual improvement of the shortcoming of the low electrical conductivity of the material, a certain amount of batteries with lithium iron phosphate as the positive electrode have been put into the market. However, the performance index of its high charge-discharge rate performance still has a certain gap compared with the actual requirements. Particle size reduction and carbon coating are the two most effective methods. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58H01M4/1397C01B25/45
CPCY02E60/12Y02E60/122Y02E60/10
Inventor 欧秀芹梁广川王丽张树涛郅晓科
Owner HEBEI UNIV OF TECH
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