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Preparation method of graphite cathode material

A graphite anode and graphitization technology, applied in battery electrodes, electrical components, circuits, etc., can solve the problems of slow initial charge and discharge, low initial charge and discharge efficiency, and low capacity.

Active Publication Date: 2011-04-27
湖北联投恒达石墨有限公司
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Problems solved by technology

[0003] Asphalt coating has a large capacity, but the initial charge and discharge speed is slow, and the initial charge and discharge efficiency is low
Resin-coated charging and discharging are fast, and the first charge and discharge efficiency is high, but the capacity is low

Method used

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Embodiment Construction

[0022] A preparation method of graphite negative electrode material, comprising the following steps:

[0023] 1) Oxidize the surface of spherical graphite, then mix it with asphalt powder, and carbonize it at 1300±100℃;

[0024] 2) Mix the carbonized spherical graphite with phenolic resin powder, and the mixed powder is cured in an acid mist environment;

[0025] 3) The cured material is carbonized at a temperature of 900±50°C;

[0026] 4) After carbonization in the previous step, the material is graphitized above 2500°C;

[0027] The graphite negative electrode material is obtained through the above steps.

[0028] The spherical graphite is obtained by spheroidizing natural flake graphite in a spheroidizer, the spherical graphite D50 is between 7-50μ, and the tap density is 0.90g / cm 3 Above, the specific surface area is 7m 2 / g or less.

[0029] The surface oxidation described in step 1) is to immerse spherical graphite in hydrogen peroxide with a mass concentration of 3...

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Abstract

The invention provides a preparation method of a graphite cathode material. In the method provided by the invention, a twice cladding method is utilized to cover the bitumencarb with resin carbon and then cover graphite particles with the bitumencarb, thereby forming a gradient structure with different carbon layers. The resin carbon layers have large intervals, and good combination with electrolyte. The resin carbon layers form stable electrolytic films, the lithium ions can enter the bitumencarb layer through the electrolyte membrane and then enter the graphite layer, and organic solvent molecules are blocked by the bitumencarb layer without being inserted into graphite pieces. In addition, the resin carbon has good mechanical strength, and the cycle life of the cathode material can be enhanced. The carbon is covered on the surface of the graphite particles to form the insertable structure for the lithium ions, thereby enhancing the inserting speed. Furthermore, the gaps of the resin carbon can store the lithium ions, thereby enhancing the capacity of the cathode material. The graphite cathode material obtained by the invention has the advantages that the capacity is above 360 mAh / g, the first cycle columbic efficiency is more than 95% and the cycle charging-discharging can be performed more than 3000 times, and rapid charging and discharging can be realized.

Description

technical field [0001] The invention relates to a method for manufacturing a negative electrode material of a lithium ion battery, in particular to a method for preparing a graphite negative electrode material. Background technique [0002] There are many ways to process carbon materials for lithium-ion battery anode materials. Natural flake graphite must be shaped and modified to improve battery performance. The methods for processing natural flake graphite as anode materials are mainly spheroidization, surface oxidation, and surface coating carbonization. graphitization. The conventional modification method is to coat pitch on the surface of spherical graphite through liquid phase or solid phase process, and then carbonize at a temperature of about 900-1300°C under nitrogen protection, or further graphitize, which can obtain a capacity of 350mAh / g, and the first efficiency is 92 %, the anode material with less than 1200 cycles. [0003] Asphalt coating has a large capaci...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/04H01M4/38
CPCY02E60/12Y02E60/10
Inventor 傅云峰
Owner 湖北联投恒达石墨有限公司
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