Novel process for preparing battery-grade iron phosphate material by using iron hydroxide

A technology of iron oxyhydroxide and iron phosphate, applied in phosphorus compounds, inorganic chemistry, chemical instruments and methods, etc., can solve the problems of difficult composition control, large discharge of three wastes, and high production cost, and achieves simple and easy process, less impurities, low cost effect

Inactive Publication Date: 2013-01-30
ZHEJIANG NARADA POWER SOURCE CO LTD +2
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Both have the disadvantages of high production cost, complicated process, difficult component control, and large discharge of three wastes.

Method used

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  • Novel process for preparing battery-grade iron phosphate material by using iron hydroxide
  • Novel process for preparing battery-grade iron phosphate material by using iron hydroxide
  • Novel process for preparing battery-grade iron phosphate material by using iron hydroxide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Embodiment 1, with reference to Figure 1-4 :

[0026] Put 2.8g of reduced iron powder (98% iron content), 6g of glacial acetic acid and 10g of citric acid in 200 ml of primary water for 2 hours. After the reaction of the reduced iron powder is complete, slowly add hydrogen peroxide (mass fraction 10%) for 2 hours until the source of zero-valent iron disappears and the solution turns orange, at which point iron oxyhydroxide is formed. Then 0.14 g of sodium dodecylbenzenesulfonate was added to the solution. After diluting 5.65g of concentrated phosphoric acid to 2 times the volume, slowly add it into the solution under stirring conditions, add dilute ammonia water to adjust the pH value to 1.5, and obtain iron phosphate precipitation. Finally, wash 4 times with 52g of water once and dry in vacuum at 90°C for 4 hours to obtain the product FePO 4 2H 2 O. X-ray powder diffraction analysis was carried out after sintering at 600°C for 6 hours, and the results showed that...

Embodiment 2

[0028] Put 14g of reduced iron powder (98% iron content), 15g of dilute hydrochloric acid, 0.56g of ethylene acid and 26.3g of citric acid in 2000ml of primary water for 2 hours. Then slowly add hydrogen peroxide (mass fraction 10%), and add hydrogen peroxide for 3 hours until the reaction of the reduced iron powder is complete, at which time iron oxyhydroxide is formed. . Another 0.14 g of Tween-80 was added to the solution. After diluting 28.25g of concentrated phosphoric acid to 3 times the volume, slowly add it into the solution under stirring conditions, add dilute ammonia water to adjust the pH value to 1.8, and obtain iron phosphate precipitation. Finally, wash 3 times with 112g of water once and dry in vacuum at 50°C for 12 hours to obtain the product FePO 4 2H 2 O.

Embodiment 3

[0030] 14g of reduced iron powder (98% iron content), 45g of dilute sulfuric acid and 5g of citric acid were stirred and reacted in primary water 2000ml for 4 hours. Then slowly add hydrogen peroxide (mass fraction 10%), and add hydrogen peroxide for 3 hours until the reaction of the reduced iron powder is complete, at which time iron oxyhydroxide is formed. Another 0.3 g of sodium lauryl sulfate was added to the solution. After preparing 32 g of ammonium phosphate into a 1 mol / L solution, slowly add it into the solution under stirring conditions to obtain iron phosphate precipitation, and add dilute ammonia water to adjust the pH value to 1.6. Finally, wash 4 times with 150g of water once and dry in vacuum at 80°C for 10 hours to obtain the product FePO 4 2H 2 O.

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Abstract

The invention discloses a novel process for preparing a low-cost battery-grade iron phosphate material by using iron hydroxide. The process comprises the following steps: mixing a zero-valent iron source and corrosive acid in a molar ratio, and adding a certain amount of primary water and ammonia water; stirring to react for 0 to 24 hours, and slowly adding hydrogen peroxide until the iron source disappears and the solution turns to orange; adding surfactant which is 1 to 5 percent that of the mass of the iron source into the solution; adding a reagent containing phosphate radicals into the solution according to a certain molar ratio of iron element to phosphor element under a stirring condition to obtain iron phosphate precipitate; filtering and washing the product 3 to 5 times with the primary water which is 3 to 7 times the weight of the iron phosphate; drying in vacuum for 4 to 12 hours at 50 and 80 DEG C to obtain FePO4.2H2O. The process for preparing battery grade iron phosphate is simple and easy to carry out and low in cost; and the prepared product has good product crystal structure, few impurities and uniform granularity and is suitable for industrial scale production; moreover, the lithium iron phosphate prepared by the process has high specific capacity, low self-discharge, high tap density, stable product performance and good processing performance.

Description

technical field [0001] The present invention relates to a preparation method of iron phosphate, a positive electrode active material precursor of a lithium ion secondary battery, in particular to a lithium iron phosphate (LiFePO 4 ) preparation method of the precursor. Background technique [0002] Traditional lead-acid batteries, nickel-cadmium batteries, and nickel-metal hydride batteries, etc., can no longer meet the needs of the market due to problems such as low energy density and environmental pollution. Compared with other secondary batteries, lithium-ion batteries have high volume energy density and mass energy density, and have the advantages of no memory effect, low self-discharge rate, long cycle life and no pollution to the environment, so they have become an advanced secondary battery. secondary battery. [0003] Lithium iron phosphate has a stable crystal structure, high specific capacity, stable discharge platform and long cycle life. It is one of the pr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/37
Inventor 姜应律蔡若愚杨国凯钟雅文
Owner ZHEJIANG NARADA POWER SOURCE CO LTD
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