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Positive electrode material of lithium ion cell and its preparation method

A technology for lithium ion batteries and positive electrode materials is applied in the field of positive electrode materials for lithium ion batteries and their preparation, and can solve the problems of sacrificing volume energy density and mass energy density, particle size distribution range, low conductivity of lithium iron phosphate, etc. Achieve the effect of improving electrochemical activity, simple method and easy operation

Inactive Publication Date: 2009-01-07
CHINA UNIV OF GEOSCIENCES (WUHAN)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For powder materials synthesized by high-temperature solid phase, the particles are coarse and the particle size distribution range is wide, which often leads to a large drop in capacity after the first charge and discharge of the material.
The hydrothermal method is suitable for the synthesis of high-purity lithium iron phosphate powder, but it is not conducive to the modification of the material, and the reversible capacity of the material synthesized by the hydrothermal method has not exceeded 80% of the theoretical capacity so far
On the other hand, the problem of low conductivity of lithium iron phosphate needs to be solved
Although coating activated carbon on the surface of the material can achieve a breakthrough in the electrical conductivity of the material, it is at the expense of volumetric energy density and mass energy density.

Method used

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  • Positive electrode material of lithium ion cell and its preparation method
  • Positive electrode material of lithium ion cell and its preparation method
  • Positive electrode material of lithium ion cell and its preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] According to the Fe and P molar ratio of 1: 1, the ferrous phosphate aqueous solution with a mass percentage concentration of 11.2% and the lithium phosphate aqueous solution with a mass percentage concentration of 9.7% are mixed uniformly, and then the OP-10 aqueous solution with a mass percentage concentration of 10% is added to carry out Mixing and stirring, where each mole of PO 4 3+ Add 10g of OP-10, control the temperature at 45-55°C to make it precipitate, then filter, wash and dry the precipitate. Heat-treat the dried precursor in a nitrogen flow at 650-800°C for 8-12.5 hours to obtain a lithium iron phosphate precursor.

[0026] With 23.6% Cu(NO 3 ) 2 The aqueous solution is mixed with lithium iron phosphate particles, and the ratio of the two is to add 0.01 mole of copper nitrate per mole of lithium iron phosphate, and stir in vacuum for 0.5h to form a paste. Then add 40% vitamin C aqueous solution, add 2.5 moles of vitamin C per mole of copper nitrate, an...

Embodiment 2

[0037] The preparation of the lithium-ion battery cathode material and the fabrication and testing of the experimental battery are the same as in Example 1. But the following parameters have changed:

[0038] The mass percent concentration of the ferrous phosphate aqueous solution is 10.9%, the mass percent concentration of the lithium phosphate aqueous solution is 9.7%; the mass percent concentration of the stabilizer OP-10 aqueous solution is 17.5%, and its addition is per mole of PO 4 3+ Add 7.5g of OP-10; the mass percent concentration of the copper nitrate solution is 33%, and its addition is 0.08 moles of copper nitrate per mole of lithium iron phosphate; the mass percent concentration of the vitamin C aqueous solution is still 40%, and its addition Add 3.5 moles of vitamin C for every mole of copper nitrate.

[0039] The tap density of the prepared lithium-ion battery positive electrode material is 1.53g / cm 3 , its initial discharge specific capacity in the experimen...

Embodiment 3

[0041] The preparation of the lithium-ion battery cathode material and the fabrication and testing of the experimental battery are the same as in Example 1. But the following parameters have changed:

[0042] The mass percent concentration of the ferrous phosphate aqueous solution is 12.2%, the mass percent concentration of the lithium phosphate aqueous solution is 10.1%; the mass percent concentration of the stabilizer OP-10 aqueous solution is 12.2%, and its addition is per mole of PO 4 3+ Add the OP-10 of 9g; The mass percent concentration of copper nitrate solution is 27%, and its add-on is that every mole lithium iron phosphate adds 0.2 mole of copper nitrate; The mass percent concentration of vitamin C aqueous solution is still 40%, and its add-on is Add 1.9 moles of vitamin C per mole of copper nitrate.

[0043] The tap density of the prepared lithium-ion battery positive electrode material is 1.57g / cm 3 , its initial discharge specific capacity in the experimental b...

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Abstract

The invention discloses an electrode material of a lithium-ion battery and a preparation method thereof. The electrode material is lithium iron phosphate (LiFePO4) with the surface coated with nano-copper and is prepared by using the following method: water solution of ferrous phosphate and lithium phosphate is evenly mixed according to a chemical formula, and is added with a stabilizer OP-10 water solution for mixing and stirring, the mixed solution is controlled at a certain temperature for precipitation, and then the precipitate is filtered, rinsed and aired. Heat treatment is carried out for an aired precursor obtained from the previous step at high temperature, therefore a lithium iron phosphate semi-finished product is obtained. The problem of the imperfect particle size of the lithium iron phosphate is solved by controlling the process conditions. Copper nitrate solution is mixed with the lithium iron phosphate semi-finished product and is added with vitamin C for reducing to obtain the copper; metal copper is evenly clad on the surface of the lithium iron phosphate particles. The preparation method has simple operational procedure; the lithium-ion battery anode material of the prepared lithium-ion battery electrode material has high ionic conductivity and electron conductivity, the 1C initial specific capacity is not less than 162mAh / g and the lC tap density is not less than 1.5g / cm<3>.

Description

technical field [0001] The invention relates to a lithium ion battery cathode material and a preparation method thereof, belonging to the field of battery materials. Background technique [0002] Lithium iron phosphate currently used as the cathode material of lithium-ion batteries has the advantages of good safety performance, excellent cycle performance, and environmental friendliness. However, according to its lithium ion deintercalation migration model, the ion conductivity and electronic conductivity of pure lithium iron phosphate The rate is low, only suitable for charging and discharging with low current density, and Li + The diffusion coefficient between lithium iron phosphate and lithium phosphate is also low. According to literature reports, the diffusion coefficient (D Li+ ) with Li 1-x FePO 4 Lithium content in the change, for lithium iron phosphate and lithium phosphate, respectively, 1.8 × 10 -14 cm 2 / s and 2.2×10 -16 cm 2 / s. The reduction of specifi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/62H01M4/04C01B25/45B22F1/02H01M4/58
CPCY02E60/10
Inventor 王圣平吴金平陈艳玲皮振邦
Owner CHINA UNIV OF GEOSCIENCES (WUHAN)
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