Oxygen-containing functional group gradient distribution reduced graphene oxide/graphene foam composite and application thereof to vanadium redox batteries

A technology of graphene foam and gradient distribution, applied in the direction of regenerative fuel cells, battery electrodes, circuits, etc., can solve the problems of excellent physical properties of destructible carbon fibers, limited electrochemical activity of graphitized carbon felt, low surface activity of graphitized carbon felt, etc. problems, to achieve the effect of improving electrocatalytic activity and electrochemical reversibility, improving energy efficiency and cycle life, and easy operation

Active Publication Date: 2016-12-07
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, oxygen reduction reaction occurs on the surface of carbon felt in vanadium batteries. Because the surface activity of graphitized carbon felt is relatively low, it is necessary to activate or modify graphitized carbon felt to improve electrochemical activity and battery performance.
[0004] Modification methods for graphitized carbon felt electrode materials, including liquid or gas phase chemical treatment, electrochemical treatment, transition metal and its oxide modification, but these methods are limited for improving the electrochemical activity of graphitized carbon felt, and are easy to damage Excellent physical properties of carbon fibers in graphitized carbon felt
In addition, the transition metals and their oxides on the carbon fibers in the modified graphitized carbon felt are not easy to exist for a long time, which makes the electrochemical performance unstable.

Method used

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  • Oxygen-containing functional group gradient distribution reduced graphene oxide/graphene foam composite and application thereof to vanadium redox batteries
  • Oxygen-containing functional group gradient distribution reduced graphene oxide/graphene foam composite and application thereof to vanadium redox batteries
  • Oxygen-containing functional group gradient distribution reduced graphene oxide/graphene foam composite and application thereof to vanadium redox batteries

Examples

Experimental program
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preparation example Construction

[0032] (1) Preparation of three-dimensional graphene foam / porous metal: On the surface of nickel foam or copper foam porous metal, graphene is grown by chemical vapor deposition to obtain three-dimensional graphene foam / porous metal;

[0033] (2) Preparation of graphene oxide / graphene foam / porous metal structure with gradient distribution of oxygen-containing functional groups: immerse graphene foam / porous metal in graphene oxide aqueous solution, heat treatment, and then place it on a metal with low reduction potential After reduction and freeze-drying, a graphene oxide / graphene foam / porous metal structure with a gradient distribution of oxygen-containing functional groups is obtained;

[0034] (3) Dissolution of porous metal: remove the porous metal with a porous metal etching solution, and obtain a graphene oxide / graphene foam structure with a gradient distribution of oxygen-containing functional groups after freeze-drying;

[0035] In the preparation method of the reduced ...

Embodiment 1

[0042] Such as figure 1 Shown, nickel foam is used as template (30 millimeters * 30 millimeters * 1.4 millimeters), adopt chemical vapor deposition method, obtain the foamed nickel of surface coating graphene, the surface density of the graphene foam that obtains is 1.5mg / cm 2 .

[0043] The graphene foam / nickel foam (9cm 2 ) is immersed in a graphene oxide aqueous solution with a concentration of 6mg / mL and pH=4 for processing, the treatment temperature is 60°C, and the time is 24h to obtain graphene oxide / graphene foam / nickel foam, wherein the surface density of graphene oxide is 1.5mg / cm 2 . Then it was placed on zinc metal for reduction for 0.5 h, and after freeze-drying, a graphene oxide / graphene foam / porous metal structure with a gradient distribution of oxygen-containing functional groups was obtained. Put into 3mol / L hydrochloric acid solution, react at 80 ℃ of temperature for 12h to dissolve nickel foam, wash repeatedly with deionized water, finally obtain the red...

Embodiment 2

[0046] The difference between Example 2 and Example 1 lies in the metal sheet of the reduced graphene oxide. First, nickel foam is used as a template (30 mm × 30 mm × 1.4 mm), and the chemical vapor deposition method is used to obtain nickel foam coated with graphene on the surface. The surface density of the graphene foam obtained is 1.5 mg / cm 2 .

[0047] Graphene foam / nickel foam (9cm 2 ) is immersed in a graphene oxide aqueous solution with a concentration of 4mg / m and pH=4 for processing, the treatment temperature is 60°C, and the time is 24h to obtain graphene oxide / graphene foam / nickel foam, wherein the surface density of graphene oxide is 1.0mg / cm 2 . Then it was placed on chromium metal with a low reduction potential for reduction for 0.5 h, and after freeze-drying, a graphene oxide / graphene foam / porous metal structure with a gradient distribution of oxygen-containing functional groups was obtained. Put it into 3mol / L hydrochloric acid solution, react at 80°C for ...

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Abstract

The invention discloses an oxygen-containing functional group gradient distribution reduced graphene oxide / graphene foam composite and an application thereof to vanadium redox batteries, belonging to the field of battery materials and energy storage. Graphene foam is obtained by a chemical vapor deposition method, a three-dimensional graphene foam and graphene oxide aerogel structure is obtained in combination with graphene oxide aerogel preparation and metals are utilized for gradient reduction, thus achieving integration of high conductivity of a thee-dimensional network of graphene and graphene oxide with abundant oxygen-containing functional groups. The composite has the advantages and beneficial effects that by using the material as the electrode material of the vanadium redox batteries, the electrocatalytic activity and electrochemical reversibility of the V<2+> / V<3+> and VO<2+> / VO2<+> oxidation reaction can be improved, the charge transfer resistance can be reduced, the energy efficiency of the vanadium redox batteries can be improved and the cycle lives of the vanadium redox batteries can be prolonged; the composite has the characteristics of simplicity and convenience in operation, high yield and easiness in structure adjustment and control and has a terrific application prospect.

Description

Technical field: [0001] The invention relates to the technical field of battery materials and energy storage, in particular to a reduced graphene oxide / graphene foam composite material with gradient distribution of oxygen-containing functional groups and its application in vanadium batteries. Background technique: [0002] All-vanadium redox flow battery (referred to as vanadium battery) is a secondary battery that utilizes the oxidation-reduction reaction of vanadium ion pairs in different valence states for electrochemical energy storage. Due to its advantages of independent output power and capacity, flexible system design, high energy efficiency, long cycle life, no emission pollution, and high safety performance, vanadium batteries have broad development prospects in large-scale energy storage and are considered to be the solution to solar energy, One of the schemes for the random and intermittent unsteady characteristics of renewable energy generation systems such as w...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/88H01M4/96H01M8/18
CPCH01M4/8825H01M4/96H01M8/18Y02E60/50
Inventor 李峰胡广剑严川伟任文才马超群徐川范新庄井明华
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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