Method for preparing carbon-coating ferric phosphate lithium

A technology of carbon-coated lithium iron phosphate and carbon source, which is applied in electrode manufacturing and other directions to achieve the effects of improving electrochemical performance, increasing discharge specific capacity and low material cost

Active Publication Date: 2009-05-27
SHANGHAI UNIVERSITY OF ELECTRIC POWER +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method can obtain lithium iron phosphate particles with small particle size, high purity and uniform particle size, but the co-precipitation synthesis method is used to directly prepare carbon-coated LiFePO 4 Composite methods have yet to be reported

Method used

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  • Method for preparing carbon-coating ferric phosphate lithium
  • Method for preparing carbon-coating ferric phosphate lithium
  • Method for preparing carbon-coating ferric phosphate lithium

Examples

Experimental program
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Effect test

Embodiment 1

[0019] (1) Add 0.1mol / L phosphoric acid solution to 0.1mol reduced iron powder under nitrogen atmosphere, mix under stirring, control the temperature at 70°C, react for 5 hours, then add 0.1mol / L LiOH solution dropwise to react 4 hours, the control temperature is 90°C, and the above reaction product is spray-dried by a high-speed centrifugal spray dryer to obtain the LiFePO4 / C precursor;

[0020] (2) In an inert or non-oxidizing atmosphere, the LiFePO4 / C precursor was transferred to a tube furnace and treated at 200 °C for 3 hours, then at 700 °C for 5 hours to obtain lithium iron phosphate. figure 1 The prepared lithium iron phosphate material (LiFePO 4 ) of the XRD spectrum, showing that the synthesized lithium iron phosphate has a good crystal structure.

Embodiment 2

[0022] (1) Add 0.1mol / L phosphoric acid solution to 0.1mol / L phosphoric acid solution under nitrogen atmosphere, add 0.1mol reduced iron powder and 0.004mol glucose, mix under stirring, control the temperature at 70°C, react for 5 hours, then add 0.1mol / L phosphoric acid dropwise LiOH solution was reacted for 4 hours, and the temperature was controlled to be 90° C., and the above reaction product was spray-dried by a high-speed centrifugal spray dryer to obtain the LiFePO4 / C precursor;

[0023] (2) In an inert or non-oxidizing atmosphere, the LiFePO4 / C precursor was transferred to a tube furnace and treated at 200 °C for 3 hours, and then at 700 °C for 5 hours to obtain coated carbonic lithium iron phosphate.

Embodiment 3

[0025] (1) Add 0.1mol / L phosphoric acid solution to 0.1mol / L phosphoric acid solution under nitrogen atmosphere, add 0.1mol reduced iron powder and 0.004mol ascorbic acid, mix under stirring, control the temperature at 70°C, react for 5 hours, then add 0.1mol / L phosphoric acid dropwise LiOH solution was reacted for 4 hours, and the temperature was controlled to be 90° C., and the above reaction product was spray-dried by a high-speed centrifugal spray dryer to obtain the LiFePO4 / C precursor;

[0026] (2) In an inert or non-oxidizing atmosphere, the LiFePO4 / C precursor was transferred to a tube furnace and treated at 200 °C for 3 hours, and then at 700 °C for 5 hours to obtain coated lithium iron phosphate. figure 2 It is a TEM photo of the material, indicating that the surface of lithium iron phosphate is covered with a loose carbon layer. from image 3It can be seen from the first charge and discharge curve of the material that the first discharge capacity of the material a...

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Abstract

The invention discloses a method for preparing carbon-coated lithium iron phosphate (LiFePO4/C). The method comprises the following steps: a, LiOH.H2O, reduced Fe powder and H3PO4 are weighed according to the molar ratio of 1:1:1 and are stirred in an aqueous solution so as to react for 2 to 10 hours under nitrogen protection; a carbon source is added to a reaction system, and an obtained suspension as a reaction product is subjected to spray drying through a high-speed centrifugal spray drying machine, so as to obtain a LiFePO4/C precursor; and b, the LiFePO4/C precursor is transferred to a tubular furnace in inert or non-oxidative atmosphere and treated for 6 to 24 hours at a temperature of between 200 and 750 DEG C, so as to obtain the LiFePO4/C. As the method adopts the Fe powder as a raw material, the specific discharge capacity of a LiFePO4/C anode material prepared by a coprecipitation method under the multiplying power between 0.1 and 2C is obviously improved.

Description

technical field [0001] The present invention relates to a preparation method of lithium iron phosphate, and more specifically relates to a method for preparing coated carbon lithium iron phosphate composite material by co-precipitation method. Background technique [0002] With the rapid development of the electronics and information industries, a large number of new mobile electronic consumer products are constantly coming out, which puts forward urgent requirements for independent power sources, especially high-energy secondary batteries. Compared with other secondary batteries, lithium ion batteries have high volumetric energy density and gravimetric energy density. Coupled with the advantages of design flexibility, long cycle life, no memory effect, low self-discharge rate, and no pollution to the environment, it has become the main choice for rechargeable power supplies in today's portable electronic products. However, the lack of resources of lithium cobalt oxide, the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/04
CPCY02E60/12Y02E60/10
Inventor 张俊喜曹小卫潘帅颜立成
Owner SHANGHAI UNIVERSITY OF ELECTRIC POWER
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