Graphene nanometer sheet-cobaltous oxide composite negative electrode material of lithium ion battery and preparation method thereof

A graphene nanosheet, lithium ion battery technology, applied in battery electrodes, cobalt oxide/cobalt hydroxide, non-aqueous electrolyte battery electrodes, etc., can solve the problems of low charge and discharge current, poor initial efficiency and cycle performance, etc. The effect of improving the contact area, excellent cycle performance and stable performance

Inactive Publication Date: 2010-08-11
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the reported CoO has a high specific capacity, its initial efficiency and cycle performance are poor, as reported in the literature J. Power Sources 2002, 109, 142, and its reversible capacity after 20 cycles is only 270mAh/g
In add...

Method used

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  • Graphene nanometer sheet-cobaltous oxide composite negative electrode material of lithium ion battery and preparation method thereof
  • Graphene nanometer sheet-cobaltous oxide composite negative electrode material of lithium ion battery and preparation method thereof
  • Graphene nanometer sheet-cobaltous oxide composite negative electrode material of lithium ion battery and preparation method thereof

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Disperse 0.5 g of graphite oxide in 400 ml of aqueous solution, ultrasonic time is 6 hours, add 2.79 g of cobalt acetate tetrahydrate, 10 ml of hydrazine hydrate, and 15 ml of ammonia water, stir and pour into a hydrothermal kettle, seal it, and heat it at 150 degrees Celsius After reacting for 5 hours, filter, wash, and dry to obtain a graphite oxide-cobalt hydroxide composite material, and treat the prepared composite at 500 degrees Celsius for 2 hours under the protection of argon to obtain graphene nanosheets-cobaltous oxide Composite negative electrode material, wherein the weight percentage of graphene nanosheets is 18.5%. figure 1 It is a transmission electron microscope image of the prepared graphene nanosheet cobaltous oxide negative electrode material. It can be clearly seen that the graphene nanosheets are interlacedly distributed on the surface of the cobaltous oxide particle. figure 2 The X-ray diffraction spectrum of the graphene nanosheet-cobaltous oxide...

Embodiment 2

[0025] Disperse 0.5 g of graphite oxide in 300 ml of isopropanol-water solution (volume ratio of 1:10), stir at room temperature for 6 hours, add 3.26 g of cobalt nitrate hexahydrate, 15 ml of ammonia, 0.08 g of sodium borohydride, and stir Pour it into a hydrothermal kettle, seal it, and react at 120 degrees Celsius for 5 hours, then filter, wash, and dry to obtain a graphite oxide-cobalt hydroxide composite material, which is treated at 300 degrees Celsius for 2 hours under nitrogen protection to obtain graphite Graphene nanosheet-cobaltous oxide composite negative electrode material, wherein the weight percentage of graphene nanosheet is 20.1%. The reversible specific capacity of the charge-discharge test at a current density of 200mA / g is 840mAh / g.

Embodiment 3

[0027] Disperse 0.5 grams of graphite oxide in 300 ml of isopropanol-water solution (volume ratio is 1:15), ultrasonic time is 2 hours, add 3.26 grams of cobalt sulfate heptahydrate, 15 milliliters of ammonia water, 0.1 grams of ascorbic acid, pour into water after stirring In a hot kettle, sealed, and reacted at 200 degrees Celsius for 10 hours, filtered, washed, and dried to obtain graphite oxide cobalt hydroxide materials, which were treated at 600 degrees Celsius for 2 hours under nitrogen protection to obtain graphene nanosheets-oxidized Sub-cobalt composite negative electrode material, wherein the weight percentage of graphene nanosheets is 17.8%. The reversible specific capacity of the charge-discharge test at a current density of 200mA / g is 930mAh / g.

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Abstract

The invention relates to a graphene nanometer sheet-cobaltous oxide composite negative electrode material of a lithium ion battery and a preparation method thereof, and belongs to the technical field of batteries. The negative electrode material consists of graphene nanometer sheets and cobaltous oxide, wherein the graphene nanometer sheets are distributed on cobaltous oxide particles in a staggering way; the mass fraction of the graphene nanometer sheets is 5 to 90 percent; the thickness of the graphene nanometer sheets is 1 to 50 nanometers; and the particle size of the cobaltous oxide is 10 to 500 nanometers. The preparation method comprises the following steps: dispersing graphite oxide in alcohol-water solution or aqueous solution with ultrasound or stirring; adding cobalt salt, alkali and a reducing agent into the mixture and pouring the mixture into a hydrothermal kettle after stirring; performing further sealing and synchronous hydrothermal reaction, washing, filtering and drying to obtain a graphene nanometer sheet-cobaltous oxide composite; and processing the graphene nanometer sheet-cobaltous oxide composite in the protective atmosphere to obtain the graphene nanometer sheet-cobaltous oxide composite negative electrode material. In the invention, when the material is charged or discharged by a current of 200mA/g, the reversible specific capacity of the material can be stabilized in a range of over 900mAh/g.

Description

technical field [0001] The invention relates to an electrode material in the field of battery technology and a preparation method thereof, in particular to a graphene nanosheet-cobaltous oxide composite negative electrode material for a lithium ion battery and a preparation method thereof. Background technique [0002] Since Nature 2000, 407, 496 reported the application of transition metal oxides as anode materials for lithium-ion batteries, many researchers have conducted in-depth studies on them. As a lithium-ion battery anode material, the theoretical specific capacity of CoO is as high as 715mAh / g, about twice that of graphitized carbon materials. Although the reported CoO has a high specific capacity, its initial efficiency and cycle performance are poor, as reported in the literature J. Power Sources 2002, 109, 142, and its reversible capacity after 20 cycles is only 270mAh / g. In addition, although the specific capacity and performance of CoO reported in the document...

Claims

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Application Information

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IPC IPC(8): H01M4/13H01M4/139H01M4/36C01B31/04C01G51/04
CPCY02E60/122Y02E60/10
Inventor 何雨石马紫峰柏大伟杨晓伟廖小珍何理
Owner SHANGHAI JIAO TONG UNIV
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