High rate LiFePO4/C positive electrode material and preparation method thereof

A cathode material, high-rate technology, applied in battery electrodes, electrical components, circuits, etc., can solve the problems of poor material consistency, difficult state control, high energy consumption, etc., to shorten the preparation cycle, expand the source, and the conductivity. high effect

Inactive Publication Date: 2015-05-20
THE NAT CENT FOR NANOSCI & TECH NCNST OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Its disadvantages: time-consuming, high energy consumption, difficult to control the state during synthesis, and poor consistency of synthesized materials

Method used

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  • High rate LiFePO4/C positive electrode material and preparation method thereof
  • High rate LiFePO4/C positive electrode material and preparation method thereof
  • High rate LiFePO4/C positive electrode material and preparation method thereof

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preparation example Construction

[0025] The present invention provides a high rate LiFePO 4 / C The preparation method of the positive electrode material, wherein, the method comprises: mixing the phosphorus source aqueous solution, the lithium source aqueous solution, the divalent iron source aqueous solution with the dispersant and / or the surfactant uniformly; performing a hydrothermal reaction on the uniformly mixed solution, The temperature of the hydrothermal reaction is 120°C-250°C; the precipitate is separated from the material after the hydrothermal reaction, and the precipitate is washed and then subjected to the first drying; Second drying, and then sintering, the sintered solid is cooled.

[0026] In the present invention, the washing method can be carried out according to the conventional methods in the art, generally using deionized water, absolute ethanol and acetone to wash several times at a time, which is well known to those skilled in the art and will not be described in detail here.

[0027...

Embodiment 1

[0047] The concentration of 5mL is the phosphoric acid solution of 1M (unit M represents mol / L, this is well known to those skilled in the art), the concentration of 15mL is the lithium hydroxide solution of 1M and the concentration of 10mL is the ferrous sulfate solution of 0.5M, press Sequentially added to 120 mL of tetraethylene glycol, and stirred uniformly under a protective atmosphere. The mixture was transferred to a hydrothermal reactor, and kept at 140 °C for 24 hours under hydrothermal conditions; after naturally cooling to room temperature, the hydrothermally obtained product was centrifuged to obtain a lithium iron phosphate precipitate; and the product was used for Ionized water, absolute ethanol and acetone were washed several times; then the cleaned product was dried in a vacuum drying oven at 60 ° C for 12 h to obtain a lithium iron phosphate sample; 15% by weight of ascorbic acid ( That is, the weight ratio of ascorbic acid to lithium iron phosphate sample is ...

Embodiment 2

[0049] Prepare LiFePO according to the method of Example 1 4 / C positive electrode material, the difference is that the carbon source is glucose, and its addition amount is 20% by weight (that is, the weight ratio of glucose to lithium iron phosphate sample is 20:100), and the other conditions are the same to obtain carbon-coated Lithium iron phosphate (LiFePO) cathode material for lithium ion batteries 4 ) nanorods (X-ray powder diffraction analysis showed that the product was pure lithium iron phosphate (LiFePO 4 ); using the product as the positive electrode material, an experimental button-type lithium-ion battery was assembled in an argon-protected glove box, and the charge-discharge cycle was performed between 2.0-4.2V at different rates, and the discharge capacity at 0.1C was 155mAh / g, 1C The discharge capacity is 140 mAh / g, showing excellent electrochemical performance).

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Abstract

The invention provides a high rate LiFePO4/C positive electrode material and a preparation method thereof. The method comprises the following steps: uniformly mixing an aqueous solution of a phosphorus source, an aqueous solution of a lithium source and an aqueous solution of a divalent iron source with a dispersant and/or a surfactant; carrying out a hydrothermal reaction on the above obtained uniformly mixed solution at 120-250DEG C; separating out a precipitate from a material obtained after the hydrothermal reaction, washing the precipitate, and carrying out first stage drying on the precipitate; and uniformly mixing the obtained first stage dried solid with a carbon source, carrying out second stage drying, sintering the obtained solid, and cooling the sintered solid. The particle size of lithium iron phosphate (LiFePO4) synthesized through the method along b direction (the lithium ion diffusion direction) is 20-200nm, and the LiFePO4/C positive electrode material has the advantages of small particle size and uniform distribution of particles, high phase purity, improvement of the diffusion performance and the electrochemical performances of lithium ions in the lithium iron phosphate material, high conductivity, large specific capacity and good cycle life.

Description

technical field [0001] The invention belongs to the technical field of electrochemical power supply material preparation, relates to a carbon-coated lithium iron phosphate material, and in particular relates to a high-rate LiFePO 4 The preparation method of / C cathode material has a very broad application prospect in the field of cathode materials commonly used in secondary lithium-ion power and energy storage batteries. Background technique [0002] Based on the current serious energy crisis and pollution problems, the research and development of new renewable and clean energy such as wind, electricity and solar energy is one of the most decisive technological fields in the world economy in the future. As a new generation of green high-energy batteries, lithium-ion batteries have great advantages in green energy storage and conversion due to the advantages of high operating voltage, high specific energy, high specific power, long cycle life, small self-discharge, and no mem...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58H01M4/62
CPCH01M4/5825H01M4/625Y02E60/10
Inventor 田瑞源褚卫国王汉夫
Owner THE NAT CENT FOR NANOSCI & TECH NCNST OF CHINA
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