Method for preparing lithium iron phosphate

A technology of lithium iron phosphate and iron phosphate powder, which is applied in chemical instruments and methods, phosphorus compounds, structural parts, etc., and can solve problems such as difficult control of shape and particle size, numerous processes, and complex preparation methods of lithium iron phosphate

Inactive Publication Date: 2008-07-02
海宁市盐官工业投资有限公司
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  • Summary
  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The object of the present invention is to overcome the disadvantages of low initial discharge specific capacity of the battery made of lithium ferrous phosphate prepared in the prior art, complex preparation method of lithium ferrous phosphate, numerous procedures, and difficulty in controlling the shape and particle size, and to provide a battery made of lithium iron phosphate The first discharge specific capacity after the battery is high, the method is simple, the process is less, and the preparation method of lithium ferrous phosphate is easy to control the shape and particle size

Method used

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Examples

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preparation example Construction

[0008] The preparation method of lithium ferrous phosphate of the present invention comprises mixing ferric salt, phosphoric acid and / or phosphate, ammonia and / or an aqueous solution of an organic amine with 1-4 carbon atoms to obtain a mixture, and mixing the The mixture is spray-dried to obtain a solid powder, and the solid powder is roasted at a temperature of 300-900° C. for 2-24 hours to obtain iron phosphate powder. The obtained iron phosphate powder Mix evenly with lithium salt and carbon source, and sinter under inert gas and / or reducing gas.

[0009] According to the present invention, the iron salt is one or more of iron nitrate, iron chloride, and organic acid iron salts with 1-4 carbon atoms. The phosphate is one or more of ammonium phosphate, ammonium hydrogen phosphate, ammonium dihydrogen phosphate, sodium phosphate, sodium hydrogen phosphate, sodium dihydrogen phosphate, potassium phosphate, potassium hydrogen phosphate, and potassium dihydrogen phosphate.

[...

Embodiment 1

[0019] This example illustrates the preparation method of lithium iron phosphate provided by the present invention.

[0020] Add 1 mole of ferric nitrate and 1 mole of phosphoric acid into 50 liters of ammonia solution to obtain a mixture. The concentration of the ammonia solution is 0.02 mol / liter. The above mixture is spray-dried in a spray dryer (Changzhou Changhong Drying Equipment Co., Ltd., LPG-5) to obtain a solid powder, which is calcined at a temperature of 500° C. for a period of After 6 hours, 148 grams of iron phosphate powder was obtained. The spray drying temperature was 100° C. and the pressure was 4 MPa. The iron phosphate powder was ball milled with 74 grams of lithium carbonate and 10 grams of sucrose in a ball mill (Nanjing University Instrument Factory, QM-ISP-20). The speed of the ball mill was 1000 rpm for 6 hours. Then, the ball-milled mixture was sintered under a nitrogen atmosphere at a temperature of 800° C. for 15 hours to obtain lithium iron phosph...

Embodiment 2

[0025]Lithium ferrous phosphate was prepared according to the method in Example 1, except that the iron phosphate powder was uniformly mixed with 74 grams of lithium carbonate and 10 grams of sucrose and then directly sintered. Lithium iron phosphate A2 with a weight of 149 grams was obtained.

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Abstract

The invention relates to a method for preparing lithium iron phosphate; wherein, the method includes mixing the water solutions of a ferric salt, a phosphoric acid and/or a phosphate, and an ammonia and/or an organic amine with the carbon atom number of 1 to 4 to acquire a mixture; drying the spray of the mixture to acquire a solid powder body; roasting the solid powder body with a temperature of 300- 900 DEG C and a time of 2- 24 hours to acquire an iron phosphate powder body; mixing the acquired iron phosphate powder body with a lithium salt and a carbon source uniformly and sintering thereof under an inert gas and/or a reducing gas. The first discharging capacity of a battery made by adopting the lithium iron phosphate prepared by the invention is remarkably higher than that of a battery made by the lithium iron phosphate prepared by the prior art.

Description

technical field [0001] The invention relates to a preparation method of lithium iron phosphate. Background technique [0002] As a chemical power source with high specific capacity, lithium-ion batteries have been widely used in mobile communications, notebook computers, video cameras, cameras, portable instruments and other fields. . LiFePO 4 It is a research hotspot of positive electrode active materials for lithium-ion batteries. Preliminary studies have shown that lithium iron phosphate (LiFePO 4 ) concentrated LiCoO 2 , LiNiO 2 , LiMnO 4 The respective advantages of such materials: no precious metals, cheap raw materials, extremely rich resources; moderate working voltage (3.4V); good platform characteristics, stable voltage, large theoretical capacity (170mAh / g); stable structure, good safety performance ( O and P are firmly combined with strong covalent bonds, which makes the material difficult to decompose by oxygen evolution); high temperature performance and...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/45H01M4/58
CPCY02E60/10
Inventor 田野程堂利冯克光
Owner 海宁市盐官工业投资有限公司
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