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Method for preparing LiFeP04 material by microwave method

A microwave method and raw material technology, applied in chemical instruments and methods, electrode manufacturing, inorganic chemistry, etc., can solve the problems of incomplete reduction, large powder particle size, poor high-rate discharge performance, etc., to prevent the growth of grains , short synthesis time, rapid heating effect

Inactive Publication Date: 2004-11-17
UNIV OF SCI & TECH BEIJING
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

It has strict requirements on the synthesis temperature, and the treatment temperature is too low during the synthesis process, which will cause Fe 3+ Incomplete reduction, Fe 3+ The presence of LiFePO not only reduces the 4 The specific capacity, and make LiFePO 4 The structure is unstable, and the high temperature will cause the powder particle size to be too large, which will also lead to its poor high-rate discharge performance, which hinders the LiFePO 4 practical application, especially in the application of large power batteries
[0004] In the published articles and patents, there is no report of using the same raw material and method to synthesize the material of the present invention

Method used

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  • Method for preparing LiFeP04 material by microwave method
  • Method for preparing LiFeP04 material by microwave method
  • Method for preparing LiFeP04 material by microwave method

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example 1

[0017] The dried material was pressed into tablets, put into an alumina crucible equipped with activated carbon and insulation materials, and then the crucible was placed in a household microwave oven (frequency 2.45 GHz), the power was adjusted to low fire level 3, and the microwave was irradiated for 9 minutes. The phase analysis results of the obtained sample are shown in figure 1 . It can be seen from the XRD pattern that the synthesized product is olivine-type LiFePO 4 , no impurity phase.

[0018] The synthetic material is added with a conductive agent and a binder (20% and 5% respectively) is bonded and pressed to form a film, and a test battery is formed with metal lithium, and a constant current charge and discharge experiment is carried out. The charge and discharge current is 10mA / g, and the charge and discharge voltage range Control between 2.0-4.5V. figure 2 The 12th charge and discharge curve is given, and the specific capacity can reach more than 100mAh / g. ...

example 2

[0020] Press the dry material into tablets, put it into an alumina crucible equipped with activated carbon and heat-insulating materials, then place the crucible in a household microwave oven (frequency 2.45 GHz), adjust the power to the second gear of low heat, and microwave for 9 minutes. The phase analysis results of the obtained sample are shown in image 3 . It can be seen from the XRD pattern that the synthesized product is olivine-type LiFePO 4 , basically no impurity phase.

[0021] The synthetic material is added with a conductive agent and a binder (20% and 5% respectively) is bonded and pressed to form a film, and a test battery is formed with metal lithium, and a constant current charge and discharge experiment is carried out. The charge and discharge current is 10mA / g, and the charge and discharge voltage range Control between 2.5-4.2V. Figure 4 The 2-7 charge and discharge curves are given, and the specific capacity can reach more than 70mAh / g.

example 3

[0023] Press the dry material into tablets, put it into an alumina crucible equipped with activated carbon and insulation materials, then place the crucible in a household microwave oven (frequency 2.45 GHz), adjust the power to medium and low heat, and microwave for 3 minutes. The phase analysis results of the obtained sample are shown in Figure 5 . It can be seen from the XRD pattern that the synthesized product is olivine-type LiFePO 4 , no impurity phase.

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Abstract

The invention provides a method for using microwave method to produce LiFePO4 material, the character lies in: it uses microwave synthesis technology, uses the active carbon as the heating material for microwave receptor, thus the LiFePO4 material can be acquired. The process is: the Li2CO3 and FeC2O4íñ2H2O, (NH4) 2HPO4 are confected according to the resultant's proportion, they are put into the agate ball milling pot, uses the acetone as dispersant to ball grind for 4-12 hours, the mixed material are dried and pressed into pieces, and put into the aluminum crucible containing the active carbon and thermal retardation material, then the crucible is put into the household microwave stove, the frequency is 2.45GHz, the power is adjusted to the lower gear-middle gear, the time is 3-30 minutes, the synthesized product can be acquired. The merits of the invention lie in: the heating process is quick, the synthesizing time is short, and it prevents the crystal particle from growing; the energy consumption can be reduced.

Description

technical field [0001] The invention belongs to the technical field of preparation of composite anion cathode materials for lithium ion batteries, and in particular provides a method for preparing LiFePO by using a microwave method. 4 The method of the material can be used as a composite anion cathode material for a lithium ion battery. technical background [0002] In recent years, around urban environmental protection and the research and development of electric vehicles, in order to solve the safety and price problems of lithium-ion batteries, people have been exploring and researching new materials. In 1997, the Goodenough group developed and studied composite anionic materials with an olivine structure. This is a class of excellent candidate materials for the positive electrode of lithium-ion batteries. It is cheap, non-toxic, and non-polluting to the environment. The representative LiFePO 4 The theoretical capacity of the material can reach 170mAh / g, and the reversib...

Claims

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Application Information

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IPC IPC(8): C01B25/00C01D15/00C01G1/02C01G49/00H01M4/02H01M4/04H01M4/48H01M4/58
CPCH01M4/5825H01M4/1397Y02E60/122C01B25/45Y02E60/10
Inventor 仇卫华李发喜赵海雷胡环宇
Owner UNIV OF SCI & TECH BEIJING
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