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Composite anode material of graphene nanoflakes and cobalt hydroxide for lithium ion battery and preparation method thereof

A technology of graphene nanosheets and lithium-ion batteries, which is applied in battery electrodes, circuits, electrical components, etc., can solve the problems of first-time charge-discharge efficiency and cycle performance, cumbersome process steps, low conductivity, etc., and achieve excellent Cyclic performance, simple preparation process, and the effect of improving electrical conductivity

Inactive Publication Date: 2010-10-20
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0002] Cobalt hydroxide has been widely used in nickel-metal hydride batteries, and it has also been widely studied and synthesized as a precursor of lithium-ion battery electrode materials, but it is all to be sintered into cobalt oxides (CoO or Co 3 o 4 ), it can be used as an electrode material for lithium-ion batteries, and the process route used is cumbersome and consumes a lot of energy
In addition, despite the reported CoO or Co 3 o 4 The material has a high specific capacity, but its first charge and discharge efficiency and cycle performance need to be improved. For example, according to the report of the document J.Power Sources2002, 109, 142, the reversible capacity of the prepared CoO material after 20 cycles is only 270mAh / g; Co prepared by the literature ElectrochimicaActa 2008, 53, 2507 3 o 4 Under the charge and discharge current density of 100mA / g, the reversible capacity of the material is only 400mAh / g
[0003] Due to the fact that cobalt hydroxide contains hydroxide ions and its own low conductivity, there are no reports of using it as an electrode material for lithium-ion batteries.

Method used

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  • Composite anode material of graphene nanoflakes and cobalt hydroxide for lithium ion battery and preparation method thereof
  • Composite anode material of graphene nanoflakes and cobalt hydroxide for lithium ion battery and preparation method thereof
  • Composite anode material of graphene nanoflakes and cobalt hydroxide for lithium ion battery and preparation method thereof

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Effect test

Embodiment 1

[0024] 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 the graphene nanosheet-cobalt hydroxide negative electrode material, wherein the weight percentage of the graphene nanosheet is 24.6%. figure 1 In a is cobalt hydroxide prepared under the same conditions, figure 1 b is the graphene nanosheets prepared under the same conditions and figure 1 c is a transmission electron microscope image of the graphene nanosheet-cobalt hydroxide negative electrode material, and it can be clearly seen that the graphene nanosheets are interlacedly distributed on the surface of the cobalt hydroxide particle. figure 2 The X-ray diffraction spectrum of the graphene nanosheet-cobalt hydroxide anode material can s...

Embodiment 2

[0026] 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 into a hydrothermal kettle, seal, and filter, wash, and dry after reacting at 120 degrees Celsius for 5 hours to obtain a graphene nanosheet-cobalt hydroxide negative electrode material, wherein the weight percentage of graphene nanosheets is 25.5 %. The reversible specific capacity of the charge-discharge test at a current density of 200mA / g is 820mAh / g.

Embodiment 3

[0028] 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 a graphene nanosheet-cobalt hydroxide negative electrode material, wherein the weight percentage of the graphene nanosheet is 23.9%. The reversible specific capacity of the charge-discharge test at a current density of 200mA / g is 905mAh / g.

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Abstract

The invention provides a composite anode material of graphene nanoflakes and cobalt hydroxide for a lithium ion battery and a preparation method thereof. The anode material is composed of graphene nanoflakes and cobalt hydroxide, wherein the graphene nanoflakes are in interlaced distribution on the cobalt hydroxide particles; the mass fraction of the graphene nanoflakes is 10-90% and the thickness thereof is 1-50 nanometers; the particle diameter of the cobalt hydroxide is 0.5-30 micrometers. The preparation method comprises the following steps: carrying out ultrasound or stirring on graphite oxide firstly to disperse in alcohol-water solution or water solution; adding cobalt salt, alkali and reductive agent to the solution; pouring the solution into a hydrothermal reactor after being stirred; and then sealing, reacting, filtering, washing and stoving the solution. As the anode material charges or discharges in 200 mA / g electric current, the reversible specific capacity of the composite material can be stabilized to be above 900 mAh / 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 lithium-ion battery graphene nanosheet-cobalt hydroxide composite negative electrode material and a preparation method thereof. Background technique [0002] Cobalt hydroxide has been widely used in nickel-metal hydride batteries, and it has also been widely studied and synthesized as a precursor of lithium-ion battery electrode materials, but it is all to be sintered into cobalt oxides (CoO or Co 3 o 4 ), it can be used as an electrode material for lithium-ion batteries, and the process route used is cumbersome and consumes a lot of energy. In addition, despite the reported CoO or Co 3 o 4 The material has a high specific capacity, but its first charge and discharge efficiency and cycle performance need to be improved. For example, according to the report of the document J.Power Sources2002, 109, 142, the reversible...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/139
CPCY02E60/122Y02E60/10
Inventor 何雨石马紫峰柏大伟杨晓伟廖小珍曾令杰
Owner SHANGHAI JIAO TONG UNIV
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