Preparation method of lithium iron phosphate

A lithium iron phosphate and ferrous phosphate technology, applied in electrical components, battery electrodes, circuits, etc., can solve the problems of small specific capacity, difficult to stabilize electrical properties, poor electrical conductivity of lithium iron phosphate, etc. The effect of stable chemical properties and high electrical conductivity

Active Publication Date: 2010-09-08
黄博
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] The purpose of the present invention is to provide a liquid-phase preparation method for lithium iron phosphate to overcome the shortcomings of poor electrical conductivity, small specific capacity and difficult to stabilize electrical properties of lithium iron phosphate, which is a positive electrode material for lithium ion batteries, by the method. The lithium iron phosphate products have excellent electrical conductivity, large specific capacity, and uniform grain size

Method used

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  • Preparation method of lithium iron phosphate
  • Preparation method of lithium iron phosphate
  • Preparation method of lithium iron phosphate

Examples

Experimental program
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Effect test

Embodiment 1

[0027] Dissolve 1 mol of ferric nitrate in water to form a ferric ion solution with a concentration of 1 mol / L, add ascorbic acid that is 100% of the molar percentage of ferric ions, and then add a concentration of 1.5 mol / L with a molar ratio of Fe:P of 1:0.6 Phosphoric acid solution, add sodium hydroxide solution to adjust the pH to 11, filter to obtain ferrous phosphate precipitate, and dry the ferrous phosphate precipitate at 150°C for 9 hours. Disperse ferrous phosphate in water, add a phosphoric acid solution with a molar ratio of Fe:P of 1:0.35, heat the mixed solution to 60°C, and stir for 2 hours; slowly add a molar ratio of Fe:Li to the mixed solution of 1:0.95 Lithium hydroxide solution, and stirred for 3 hours to obtain a suspension. Subsequently, glucose with a mass of 5% of the ferrous phosphate mass was dissolved in water, and slowly added to the suspension, stirred for 2 hours, and then spray-dried to obtain a lithium iron phosphate precursor. The lithium iron...

Embodiment 2

[0029] 1mol ferric chloride is dissolved in water, is configured as the iron ion solution that concentration is 2mol / L, adds the ascorbic acid that is 100% of iron ion molar percentage, then adds concentration is 1mol / L, and molar ratio Fe:P is 1:0.62 ammonium dihydrogen phosphate solution, and potassium hydroxide was added to adjust the pH value to 10, the ferrous phosphate precipitate was obtained by filtration, and the ferrous phosphate precipitate was dried at 150°C for 9 hours. Disperse ferrous phosphate in water, add a phosphoric acid solution with a molar ratio of Fe:P of 1:0.38, heat the mixed solution to 70°C, and stir for 3 hours; slowly add a molar ratio of Fe:Li to the mixed solution Lithium hydroxide solution, and stirred for 2 hours to obtain a suspension. Subsequently, sucrose whose mass is 10% of the mass of ferrous phosphate is dissolved in water, slowly added into the suspension, stirred for 3 hours, and then spray-dried to obtain a lithium iron phosphate pre...

Embodiment 3

[0031]1mol ferrous chloride is dissolved in water, is configured into the ferrous ion solution that concentration is 1.5mol / L, adds the ascorbic acid that is 3% of ferrous ion mole percentage, then adds concentration and is 1mol / L, molar ratio Fe:P Diammonium hydrogen phosphate solution of 1:0.7, adding sodium hydroxide to adjust the pH value to 11, filtering to obtain ferrous phosphate precipitate, and drying the ferrous phosphate precipitate at 170°C for 6 hours. Disperse ferrous phosphate in water, add a phosphoric acid solution with a molar ratio of Fe:P of 1:0.3, heat the mixed solution to 70°C, and stir for 3 hours; slowly add a molar ratio of Fe:Li to the mixed solution Lithium hydroxide solution, and stirred for 2 hours to obtain a suspension. Dextrin whose mass is 5% of the mass of ferrous phosphate is dissolved in water, and slowly added into the suspension. After stirring for 3 hours, the lithium iron phosphate precursor was obtained by spray drying. Lithium iron ...

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Abstract

The invention provides a preparation method of lithium iron phosphate, which comprises the following steps: 1, dissolving an iron source in water to obtain ferric ion/ferrous ion; adding ascorbic acid, phosphorus source solution and aqueous alkali and adjusting the pH value; and filtering to obtain ferrous phosphate sediment and drying the ferrous phosphate sediment; 2, dispersing the ferrous phosphate into the deionized water, adding phosphoric acid solution, heating and mixing the solution and stirring; and adding a lithium source solution into the mixed solution for reaction to obtain suspension; 3 dissolving a sugar source into the water and adding into the suspension obtained in step 2, stirring and drying to obtain the precursor of lithium iron phosphate; and 4, under the protection of inert gas, increasing, keeping and then reducing the temperature of the lithium iron phosphate obtained in step 3, to obtain lithium iron phosphate; and crushing lithium iron phosphate until the particle size is less than 15 mu m, to obtain the finished product. The lithium iron phosphate product prepared by the method of the invention has perfect electrical conductivity, large specific capacity and uniform particle size.

Description

Technical field: [0001] The invention relates to a preparation method of an energy functional material, in particular to a preparation method of lithium iron phosphate which is a cathode material of a lithium ion battery. Background technique: [0002] Lithium-ion batteries have the advantages of high platform voltage, good cycle performance, wide operating temperature range, high energy density, and no memory effect. They are widely used in mobile communications, portable electronic products, power tools, and weapon assembly. They are currently used in power vehicles It also has broad application prospects. Therefore, it is of great theoretical significance and use value to develop new lithium-ion batteries with excellent electrochemical performance and safety, and the key is to prepare stable and usable cathode materials for lithium batteries. [0003] At present, the most commercialized lithium battery on the market is lithium cobalt oxide battery. However, due to the cr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/1397
CPCY02E60/122Y02E60/10
Inventor 黄博
Owner 黄博
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