Method for preparing carbon-coated LiFePO4 for lithium ion batteries

A carbon-coated technology for lithium iron phosphate and phosphoric acid, which is applied in electrode manufacturing, electrical components, battery electrodes, etc., can solve the problems of complex preparation process, high raw material cost, poor product quality, etc., and achieves simple process and high capacity. , the effect of perfect crystallization

Inactive Publication Date: 2010-06-30
孙琦
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the process of raw material production, storage and transportation, measures need to be taken to prevent the oxidation of divalent iron source, so the cost is high
Therefore, in the prior art, there are generally prominent shortcomings such as high cost of raw materials, complicated preparation process, poor product quality, and low cost performance.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Mix phosphoric acid, superfine iron powder and glucose, and dry at 80°C, wherein the molar ratio of Fe and P is 1:1, and the mass of glucose is 10% of the mass of ferric oxide; add lithium acetate, add water and mix , where the molar ratio of Li and P is 1:1. After the product was dried at 160°C, it was transferred to an atmosphere-protected microwave oven. The microwave sintering temperature was 500°C, and the sintering time was 15 minutes. The measured capacity at 1C was 130mAh / g, and the capacity was basically not attenuated after 50 cycles.

Embodiment 2

[0025] Mix phosphoric acid, ultrafine iron powder, manganese carbonate and sucrose, and dry at 160°C, wherein the molar ratio of Fe, Mn and P is 0.95:0.05:1, and the mass of sucrose is 15% of the mass of ferric oxide; Add lithium carbonate, add water and mix, wherein the molar ratio of Li and P is 0.95:1; after drying the product at 100°C, transfer it to an atmosphere-protected microwave oven, the microwave sintering temperature is 600°C, and the sintering time is 30 minutes; measured Its 1C capacity is 129mAh / g, and the capacity has basically no attenuation after 50 cycles.

Embodiment 3

[0027] Mix phosphoric acid, superfine iron powder, nickel nitrate and starch, dry at 100°C, wherein the molar ratio of Fe, Ni and P is 0.98:0.02:1, and the quality of starch is 20% of the quality of ferric oxide; Add a mixture of lithium hydroxide and lithium carbonate, add water and mix, wherein the molar ratio of Li and P is 1.05:1, and the molar ratio of lithium acetate and lithium carbonate is 2:1; dry the product at 80°C and transfer it to the atmosphere In a protected microwave oven, the microwave sintering temperature is 700°C, and the sintering time is 10 minutes; the measured capacity at 1C is 127mAh / g, and the capacity has basically no decay after 50 cycles.

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PUM

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Abstract

The invention relates to a method for preparing carbon-coated LiFePO4 (lithium iron phosphate) for lithium ion batteries, belonging to the technical field of new energy materials. The synthesis process of the invention comprises the following steps: mixing and drying ultra-fine iron powder, phosphoric acid, simple organic matter and doping element compounds with the molar ratio of phosphate ions, iron ions and doping element ions being 1:y:z, wherein y is larger than or equal to 0.95 and smaller than or equal to 1, and the sum of y and z is 1; adding lithium-source compounds and water to the mixture in sequence, remixing and drying, wherein the molar ratio between the lithium ions and the phosphate ions is x:1, and x is larger than or equal to 0.95 and smaller than or equal to 1.05; and sintering the mixture on a microwave temperature at 500 to 950 DEG C for 5 to 40 minutes in the vacuum atmosphere or the non-oxidizing atmosphere. The ultra-fine iron powder is used as microwave absorption media and iron source materials, so as to the iron powder is capable of rapidly absorbing the microwave energy to cause the solid-phase reaction to be rapidly conducted. Compared with the prior art, the invention has the advantages of simple technological process and easily controllable operation; and the final product has the advantages of high purity, complete crystallization, high capacity and good cycle stability.

Description

technical field [0001] The invention relates to a preparation method of high-performance carbon-coated lithium iron phosphate, which belongs to the technical field of new energy materials. Background technique [0002] Lithium-ion battery is a superior battery system, which has the characteristics of high energy density, no memory effect, no pollution, and long life. With the advancement of lithium-ion battery technology, it also has the characteristics of high safety and can be made into any shape, so it is an ideal energy storage device. At present, lithium-ion batteries are widely used in various electronic devices, such as notebook computers, mobile phone batteries, digital cameras, portable lighting equipment, etc. At the same time, it is also used in electric tools, electric bicycles and electric vehicles. With the gradual consumption of the world's oil resources and the gradual improvement of society's requirements for environmental protection, electric vehicles hav...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/04H01M4/58H01M4/62
CPCY02E60/12Y02E60/10
Inventor 孙琦朱小奕胡章勇
Owner 孙琦
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