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Preparation method for carbon-encapsulated lithium ion battery cathode material LiFePO4/C

A lithium-ion battery, cathode material technology, applied in battery electrodes, circuits, electrical components, etc., can solve problems such as material performance degradation, and achieve the effects of improving electrochemical performance, improving electronic conductivity, and improving interface environment.

Inactive Publication Date: 2011-11-16
SHANGHAI UNIVERSITY OF ELECTRIC POWER
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the process of implementation, elemental iron will be produced due to carbothermal reduction, which will lead to the generation of impurity phases in the synthetic materials and the degradation of material properties.

Method used

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  • Preparation method for carbon-encapsulated lithium ion battery cathode material LiFePO4/C
  • Preparation method for carbon-encapsulated lithium ion battery cathode material LiFePO4/C
  • Preparation method for carbon-encapsulated lithium ion battery cathode material LiFePO4/C

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preparation example Construction

[0031] (1) Preparation of lithium iron phosphate electrode: adopt the obtained sample of the present invention as positive electrode material. Electron conductive material (acetylene black) and binder (polytetrafluoroethylene) are added during preparation. The ratio between the components is calculated by mass: positive electrode material of lithium ion battery: electronically conductive material: binder = 82:10:8.

[0032] (2) The negative electrode adopts metal lithium sheet.

[0033] (3) Battery assembly: The electrolyte uses ethyl carbonate: methyl ethyl carbonate: diethyl carbonate = 1:1:1 (wt%) as the solvent, and 1mol / L lithium hexafluorophosphorus (LiPF6 ) is the electrolyte of the electrolyte. The lithium iron phosphate electrode is used as the positive electrode, and the lithium sheet is used as the negative electrode to assemble the battery.

[0034] The cyclic voltammetry curve test of the present invention: the negative electrode lithium sheet is used as the co...

Embodiment 1

[0037] A preparation method of carbon-coated lithium-ion battery cathode material LiFePO4 / C, the steps are as follows:

[0038] First, add 5ml of deionized water to a 50ml ball mill jar, add 3.41ml of phosphoric acid and 2.6667g of ferric oxide, mix the materials evenly, and mill them on a ball mill for 2 hours, then add 0.9309g of iron powder and auxiliary reducing agent (1.09g Ascorbic acid or 1.6776g glucose) was ball milled for 2 hours, and finally 2.098g lithium hydroxide was added to continue ball milling on the ball mill for 2 hours to obtain the lithium iron phosphate precursor;

[0039] The precursor is calcined at a temperature of 600-800° C. for 5 hours under the protection of an inert gas N2 to obtain LiFePO4 / C, which are respectively ascorbic acid and glucose-coated cathode composite materials for lithium-ion batteries.

Embodiment 2

[0041] The preparation method of lithium-ion battery cathode material LiFePO without adding auxiliary reducing agent, the steps are as follows:

[0042]First, add 5ml of deionized water to a 50ml ball mill jar, add 3.41ml of phosphoric acid and 2.6667g of ferric oxide, mix the materials on a ball mill for 2 hours, then add 0.9309g of iron powder and continue to mill for 2 hours, and finally add 2.098 g lithium hydroxide continues to be milled on the ball mill for 2 hours to obtain the lithium iron phosphate precursor;

[0043] The precursor is calcined at a temperature of 600-800° C. for 5 hours under the protection of an inert gas to obtain the positive electrode material of lithium ion battery --- the lithium ion battery positive electrode material LiFePO4 without carbon coating.

[0044] figure 1 It is the XRD test result of the lithium ion battery positive electrode material LiFePO4 / C that is respectively ascorbic acid and glucose that are carried out carbon coating in em...

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Abstract

The invention discloses a preparation method for a carbon-encapsulated lithium ion battery cathode material LiFePO4 / C. The preparation method comprises the following steps of: dispersing iron trioxide, a reducing agent, an auxiliary reducing agent, phosphoric acid and lithium hydroxide through ball-milling, and sintering at a high temperature to obtain the carbon-encapsulated lithium ion battery cathode composite material LiFePO4 / C, wherein the used reducing agent is iron powder; and the used auxiliary reducing agent is ascorbic acid or glucose. In the preparation method, the iron powder is used as the reducing agent, so the defect that an impurity phase occurs because elementary iron is generated through over reduction of carbon in the conventional method for preparing lithium iron phosphate through Fe2O3 carbonthermal reduction is avoided; the raw material Fe2O3 is a byproduct in the production of the iron and steel industry, so that the aim of reducing production cost is fulfilled; the auxiliary reducing agent is used, so the iron powder and Fe2+ component cannot be contacted with air to avoid oxidization in the process of synthesis; and the specific capacity of charging-discharging of the material is increased through carbon encapsulation of the auxiliary reducing agent in high temperature sintering.

Description

technical field [0001] The invention relates to a preparation method of a lithium ion battery cathode material, in particular to a preparation method of a carbon-coated lithium ion battery cathode material LiFePO4 / C. Background technique [0002] The mainstream trend of battery development is to change to green and environment-friendly, among which new batteries such as lithium-ion batteries and fuel cells are developing rapidly; in order to meet the concept of sustainable development, secondary rechargeable batteries will gradually replace primary batteries; new batteries are further miniaturized, Lightweight direction development. Lithium-ion batteries have the advantages of high working voltage, light weight, large actual charge-discharge specific capacity, long cycle life, and are environmentally friendly batteries. They are widely used in transportation, transportation, communications, office automation, mineral exploration, military weapons, etc. It plays an extremely...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/1397
CPCY02E60/122Y02E60/12Y02E60/10
Inventor 张俊喜许明玉杨希顾志浩严锦程宋锴焱马行驰
Owner SHANGHAI UNIVERSITY OF ELECTRIC POWER
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