Preparation method of lithium iron phosphate positive electrode material precursor

A positive electrode material, lithium iron phosphate technology, applied in the field of lithium ion battery cathode material preparation, can solve the problems of poor uniformity, high energy consumption, long grinding time of lithium iron phosphate precursor, etc., achieve small particle size, save cost, and reduce synthesis Effects of Time and Energy Consumption

Inactive Publication Date: 2018-08-24
KUNMING UNIV OF SCI & TECH
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Problems solved by technology

[0005] In view of the disadvantages of long grinding time, high energy consumption, poor uniformity and repeated drying of iron phosphate raw materials in the preparation of lithium iron phosphate precursor by traditional high-temperature solid-phase synthesis method in the prior art, the present invention provides a lithium iron phosphate cathode material precursor body preparation method

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  • Preparation method of lithium iron phosphate positive electrode material precursor
  • Preparation method of lithium iron phosphate positive electrode material precursor
  • Preparation method of lithium iron phosphate positive electrode material precursor

Examples

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Embodiment 1

[0025] Such as figure 1 As shown, the preparation method of the lithium iron phosphate positive electrode material precursor, its specific steps are as follows:

[0026] Step 1. Mix iron source (iron powder) and phosphorus source (phosphoric acid, concentration 40wt%) according to the molar ratio of Fe:P 1:1 and then prepare a solution. Control the pH value of the solution to 2, and add 1.3 moles of Fe Double hydrogen peroxide, combined reaction at 60°C for 2 hours, aged at room temperature for 4 hours to obtain ferric phosphate precipitate, washed the ferric phosphate precipitate with water until the pH value of the filtered water was 7-8, and dried to obtain ferric phosphate powder;

[0027] Step 2. The lithium source (lithium carbonate) is prepared into a lithium source solution according to the molar ratio of Li:Fe:P in the iron source and phosphorus source of 1.03:1:1; the lithium source is 1:25g / mL according to the solid-liquid ratio Add deionized water, then pass in ca...

Embodiment 2

[0032] Such as figure 1 As shown, the preparation method of the lithium iron phosphate positive electrode material precursor, its specific steps are as follows:

[0033] Step 1. Mix iron source (ferrous sulfate heptahydrate) and phosphorus source (ammonium dihydrogen phosphate) according to the molar ratio of Fe:P 1:1, and add deionized water according to the solid-liquid ratio of 1:5g / mL to form Iron source solution and phosphorus source solution, drop the phosphorus source solution into the iron source solution, control the pH value of the solution to 2, add hydrogen peroxide with 1.3 times the molar number of Fe, and react at a temperature of 70°C for 2 hours, and age at room temperature After 2 hours, ferric phosphate precipitate was obtained, and the ferric phosphate precipitate was washed until the pH value of the filtered water was 7-8, and dried to obtain ferric phosphate powder;

[0034] Step 2. The lithium source (lithium hydroxide) is prepared into a lithium source...

Embodiment 3

[0039] Such as figure 1 As shown, the preparation method of the lithium iron phosphate positive electrode material precursor, its specific steps are as follows:

[0040] Step 1. Iron source (a mixture of ferrous sulfate heptahydrate and ferrous oxalate with a mass ratio of 1:1) and a phosphorus source (a mixture of ammonium dihydrogen phosphate and diammonium hydrogen phosphate with a mass ratio of 1:1) according to Fe: The molar ratio of P is 1:1, and deionized water is added according to the solid-liquid ratio of 1:10g / mL to form iron source solution and phosphorus source solution. The phosphorus source solution is added dropwise to the iron source solution, and the pH of the solution is controlled to be 2. Add hydrogen peroxide with 1.2 times the molar number of Fe, react at 70°C for 2 hours, and age at room temperature for 4 hours to obtain iron phosphate precipitation, wash the iron phosphate precipitation until the pH value of the filtered water is 7-8, and dry to obtain...

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Abstract

The invention relates to a preparation method of a lithium iron phosphate positive electrode material precursor and belongs to the technical field of preparation of positive electrode materials for lithium-ion batteries. The method comprises the steps of carrying out combination reaction and ageing on an iron source and a phosphorus source, obtaining iron phosphate precipitates, washing the iron phosphate precipitates until the pH value of filtered water is 7-8 and drying to obtain iron phosphate powder; preparing a lithium source solution from a lithium source according to the molar ratio ofLi to Fe to P in the lithium source, the iron source and the phosphorus source being (0.95-1.10):1:1; dissolving a conductive additive into an additive solution; and adding the lithium source solutionand the additive solution to the iron phosphate powder, stirring evenly and then drying to obtain the lithium iron phosphate positive electrode material precursor. According to the method, various raw materials are dissolved into the solution, so that mixing at the atomic or molecular level is achieved; ball-milling and ultrafine grinding are not needed, the used raw materials are primary raw materials and iron phosphate, and the procedures, such as drying and packaging are not needed, so that the production cost can be reduced.

Description

technical field [0001] The invention relates to a preparation method of a lithium iron phosphate positive electrode material precursor, and belongs to the technical field of lithium ion battery positive electrode material preparation. Background technique [0002] With the wide application of new energy and new energy vehicles around the world, lithium-ion batteries and their cathode materials have also developed rapidly. At present, there are many researches on the positive electrode materials of lithium ion batteries, including lithium cobaltate, lithium nickelate, lithium manganate and lithium iron phosphate. Compared with these materials, the olivine-like lithium iron phosphate cathode material has its outstanding advantages: (1) The theoretical capacity is higher, with 170mAh / g; (2) It has a discharge platform of 3.4V, which enables organic electrolysis The application range of the liquid is greatly expanded, and the discharge platform is stable; (3) The reversibility ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58H01M10/0525
CPCH01M4/5825H01M10/0525Y02E60/10
Inventor 姚耀春杨斌马文会杨桂玲梁风戴永年
Owner KUNMING UNIV OF SCI & TECH
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