Preparation of micron-size spherical LiFePO4 material

A micron-scale, spherical technology, applied in the field of lithium battery material science and electrochemistry, can solve problems such as small tap density

Inactive Publication Date: 2010-06-23
BIOCHEM ENG COLLEGE OF BEIJING UNION UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the invention is to propose a micron-scale spherical LiFePO 4 The preparation method to solve the problem of its small tap density so as to meet the needs of power batteries

Method used

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  • Preparation of micron-size spherical LiFePO4 material
  • Preparation of micron-size spherical LiFePO4 material
  • Preparation of micron-size spherical LiFePO4 material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Prepare a diammonium hydrogen phosphate solution with a concentration of 1.0 mol / L and a mixed solution of 1.0 mol / L ferrous sulfate and ammonium citrate with a molar ratio of 1:1 with deaerated deionized water; The mixed solution of ferrous iron and ammonium citrate is used as the base liquid, the temperature is controlled at 30°C, and the diammonium hydrogen phosphate solution is added dropwise with a constant flow pump while stirring. When the reaction liquid turns milky, stop the dropwise addition, react for 10 minutes, and centrifuge to separate the product , and washed with double distilled water until the clear liquid is colorless, that is, to obtain (NH 4 )FePO 4 . Will (NH 4 )FePO 4 Added to a concentration of 1wt% methyl cellulose aqueous solution, and then added with (NH 4 )FePO 4 Equimolar LiOH, ultrasonically dispersed for 5 minutes to form (NH 4 )FePO 4 Dispersion at 10% by weight. Mix Span-80 and liquid paraffin in a mass ratio of 1:100, put it in...

Embodiment 2

[0023] Prepare the diammonium hydrogen phosphate solution with a concentration of 1.75 mol / L and the mixed solution of 1.75 mol / L ferrous sulfate and ammonium citrate with a molar ratio of 1:1 with deaerated deionized water; The mixed solution of ferrous iron and ammonium citrate is used as the base solution, and the temperature is controlled at 55°C. While stirring, the diammonium hydrogen phosphate solution is added dropwise with a constant flow pump. When the reaction solution turns milky, stop the dropwise addition, react for 30 minutes, and centrifuge to separate the product , and washed with double distilled water until the clear liquid is colorless, that is, to obtain (NH 4 )FePO 4 . Will (NH 4 ) FePO 4 Added to a concentration of 3wt% methyl cellulose aqueous solution, and then added with (NH 4 ) FePO 4 Equimolar LiOH, ultrasonically dispersed for 10 minutes to form (NH 4 ) FePO 4A dispersion with a content of 20% by weight. Mix Span-80 and liquid paraffin in a...

Embodiment 3

[0025] Prepare the diammonium hydrogen phosphate solution with a concentration of 2.5mol / L and the mixed solution of ferrous sulfate and ammonium citrate with a molar ratio of 1:1 with a concentration of 2.5mol / L and ammonium citrate with deaerated deionized water; The mixed solution of ferrous iron and ammonium citrate is used as the base liquid, and the temperature is controlled at 80°C. While stirring, the diammonium hydrogen phosphate solution is added dropwise with a constant flow pump. When the reaction solution becomes milky, stop the dropwise addition, react for 50 minutes, and centrifuge to separate the product , and washed with double distilled water until the clear liquid is colorless, that is, to obtain (NH 4 ) FePO 4 . Will (NH 4 ) FePO 4 Added to a concentration of 5wt% methyl cellulose aqueous solution, and then added with (NH 4 )FePO 4 Equimolar LiOH, ultrasonically dispersed for 15 minutes to form (NH 4 )FePO 4 A dispersion with a content of 30% by weig...

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Abstract

The invention provides a method for preparing micro-sized spherical LiFePo4, belonging to the lithium cell battery material science technical field and the electrochemistry technical field. In the method of the invention, a ferrous sulphate solution and the mixed liquid of diammonium phosphate and ammonium citrate are prepared respectively, while stirring, the ferrous sulphate solution is added in the mixed liquid of diammonium phosphate and ammonium citrate, when the reaction liquids is milk-white, the addition stops, after the reaction is kept for a certain time, reaction liquids are subjected to centrifugation and washing to obtain (NH4)FePO4 with thin grain size; (NH4)FePO4 and LiOH which are the same in mol number are added in a water solution of methyl cellulose and subjected to ultra sonic dispersion to obtain dispersions; the liquid paraffin and Span-80 are uniformly mixed according to a certain ratio, dispersions are added in the oil phase while stirring, after the high-speed uniform stirring, reactants are put in the aqueous thermostat and have water in the sphere slowly evaporated for 3 to 5h and subjected to suction filtering, washing and drying to obtain spherical particles; the spherical particles are subjected to high temperature roast to obtain spherical LiFePO4 materials with the diameter between 5 and 10mu m. For the micro-sized spherical LiFePo4 prepared bythe method of the invention, the tap density is 1.55g / cm<3>, and the stable discharge specific capacity reaches 163mAh / g.

Description

technical field [0001] The invention relates to a method for preparing micron-sized spherical LiFePO 4 The preparation method belongs to the field of lithium battery material science and technology and the field of electrochemical technology. Background technique [0002] The long-term use of fossil fuels represented by the three major energy sources of coal, oil, and natural gas has made the energy structure unreasonable and seriously polluted the environment, especially as the reserves of the three major energy sources are decreasing day by day, and the resulting global warming and ecological Environmental degradation is receiving increasing attention. Therefore, to maintain the sustainable development of human society, energy and the environment are two severe issues that must be faced in the 21st century, and the development of clean and renewable new energy is one of the most decisive technical fields in the world economy in the future. In energy development, it is of...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/45H01M4/58
CPCY02E60/10
Inventor 于春洋杨宏伟刘晓宇
Owner BIOCHEM ENG COLLEGE OF BEIJING UNION UNIV
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