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Method for preparing cobalt oxide nanosheet and graphene composite lithium battery cathode material through single-mode microwave

A graphene composite, negative electrode material technology, applied in battery electrodes, circuits, electrical components, etc., can solve the problems of large particle size, low purity, poor activity of ultrafine powder, etc.

Inactive Publication Date: 2012-01-18
SHANGHAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Co3O4 ultrafine powder prepared by this method has poor activity, low purity and large particle size, and its physical and chemical properties are difficult to meet the requirements of the electronics industry; Yang Shubin et al obtained graphene-loaded Co3O4 nanoparticles under alkaline conditions (Chem.Sus.Chem., 2009, 2:236-239), The particle size is about 15nm, but its battery cycle performance is not good under high current; Lu Yan et al. prepared network Co3O4 by microwave method with good Cycling performance, the mesh pore size is about 20nm (Electrochem. Commun., 2009, 10:1-6); and the graphene and mesh Co3O4 Materials with load-forming layers are rarely studied

Method used

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  • Method for preparing cobalt oxide nanosheet and graphene composite lithium battery cathode material through single-mode microwave
  • Method for preparing cobalt oxide nanosheet and graphene composite lithium battery cathode material through single-mode microwave
  • Method for preparing cobalt oxide nanosheet and graphene composite lithium battery cathode material through single-mode microwave

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Embodiment 1

[0024] Take 2 g of natural graphite powder and add it to the flask, place the flask in ice water, keep the temperature in the ice water bath at about 0 ℃, add 80 ml of HNO 3 (65%), then magnetically stirred for 10 min, and then added 120 ml H 2 SO 4 (98%), stirred for 1 h, the temperature was about 20 ℃, slowly added 10 g KMnO 4 , to avoid a sharp rise in temperature, keep the temperature at 35 ℃, add KMnO 4 Finally, magnetic stirring was carried out for 2 h, and then 400 ml of ultrapure water was added to obtain a black colloidal substance, and then 10 ml of 30% H 2 o 2 , the solution is brownish yellow, add 30 ml of 10% HCl to wash, centrifuge at a speed of about 15000-18000 rpm, wash 3 times with ultrapure water until the sample is neutral, and finally dry to obtain graphene oxide thing;

[0025] Will Co 3 o 4 : The mass ratio of G (graphene) is set to 1:1, while Co(NO 3 ) 2 ·6H 2 O:HMT=1:2 (molar ratio), take 0.189 g Co(NO3 ) 2 ·6H 2 O was dissolved in ...

Embodiment 2

[0029] Take 2 g of natural graphite powder and add it to a 1000 mL flask, place the flask in ice water, keep the temperature in the ice water bath at about 0 °C, add 80 ml of HNO 3 (65%), then magnetically stirred for 10 min, and then added 120 ml H 2 SO 4 (98%), stirred for 1 h, the temperature was around 20 ℃, slowly added 10 g KMnO 4 , to avoid a sharp rise in temperature, keep the temperature at 35 ℃, add KMnO 4 Finally, magnetic stirring was carried out for 2 h, and then 400 ml of ultrapure water was added to obtain a black colloidal substance, and then 10 ml of 30% H 2 o 2 , the solution was brownish yellow, added 30 ml of 10% HCl to wash, centrifuged, washed 3 times with ultrapure water until the sample was neutral, and finally dried to obtain graphene oxide;

[0030] Will Co 3 o 4 The mass ratio to graphene is set at 2:1, while Co(NO 3 ) 2 ·6H 2 O:HMT=1:2 (molar ratio), take 0.377 g Co(NO 3 ) 2 ·6H 2 O was dissolved in 40 ml of absolute ethanol, ano...

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Abstract

The present invention provides a single-mode microwave synthesis method for preparing a cobalt oxide (Co3O4) nanosheet and graphene composite lithium battery cathode material with a layer-to-layer three-dimensional network structure. According to the present invention, cobaltous nitrate, hexamethylenetetramine (HMT) and natural graphite powder are adopted as raw materials, an improved Hummers method is adopted for preparing a graphene oxide; the resulting graphene oxide is added to a mixed solution comprising the cobaltous nitrate and the HMT to generate cobalt hydroxide by using the reactionof the cobaltous nitrate and the HMT under the single-mode microwave; the resulting cobalt hydroxide is subjected to pyrolysis for 2 hours at a temperature of 300 DEG C in the protection of N2; then the resulting product is placed in a muffle furnace to carry out baking for 2 hours at the temperature of 300 DEG C to obtain the sample. According to the single-mode microwave process provided by thepresent invention, the HMT is adopted as the donor for providing the hydroxyl radical, such that the cobaltous nitrate is subjected to the reaction to generate the cobalt hydroxide under the single-mode microwave; the slow decomposition of the HMT and the uniformity of the single-mode microwave reaction are adopted, such that the product has the layer-to-layer three-dimensional network structure.In addition, the electrochemical performance test is performed for the Co3O4 nanosheet and graphene composite lithium battery cathode material with the layer-to-layer three-dimensional network structure, the test result shows that, the Co3O4 nanosheet and graphene composite lithium battery cathode material has excellent lithium storage performance, and broad prospects in the field of development of the lithium ion battery cathode material.

Description

[0001] technical field [0002] The present invention relates to improved Hummers method and single-mode microwave synthesis method, specifically, preparing graphene oxide and single-mode microwave method by improving Hummers method to prepare reticular Co 3 o 4 , eventually forming a layer-by-layer structure of Co 3 o 4 / graphene synthesis method, the key of this method is that the product structure to be formed is sheet graphene and network Co 3 o 4 It belongs to the technical field of single-mode microwave preparation of new graphene composite materials and the application of lithium-ion battery negative electrode materials. [0003] Background technique [0004] Lithium-ion batteries have been valued for their high specific energy, high voltage, and wide adaptability, and have gradually replaced traditional nickel-metal hydride batteries, nickel-cadmium batteries, and lead-acid batteries, and are widely used in mobile phones, digital cameras, video cameras, digita...

Claims

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Application Information

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IPC IPC(8): H01M4/36
CPCY02E60/12Y02E60/10
Inventor 王勇陈双强顾燕陆莉婕金思易
Owner SHANGHAI UNIV
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