Cobaltosic oxide quantum dot@carbon composite electrode material and preparation method thereof

Abstract

The invention provides a preparation method of a cobaltosic oxide quantum dot@carbon composite electrode material. The method comprises the following steps: A) mixing and grinding a carbon material and a cobalt salt to obtain mixed powder, the melting point of the cobalt salt being lower than the thermal decomposition temperature; and B) under a protective atmosphere condition, heating and meltingthe mixed product, and continuously heating for pyrolysis to obtain the cobaltosic oxide quantum dot@carbon composite electrode material. According to the method, the problems of poor conductivity, volume expansion, low actual specific capacity, poor cycling stability and the like of a traditional cobaltosic oxide electrode are solved; the prepared cobaltosic oxide quantum dot@carbon composite electrode realizes confined growth of cobaltosic oxide, and cobaltosic oxide quantum dots evenly wrapped in a carbon nano cavity are obtained; due to the extremely small nanometer size, sufficient exertion of the oxidation-reduction reaction is guaranteed, and the specific capacitance of the electrode is greatly improved; and the unique confined structure inhibits the volume expansion of the electrode in the charging and discharging process, so that the overall cycling stability of the supercapacitor is improved.

Description

technical field [0001] The invention belongs to the technical field of supercapacitors, and in particular relates to a cobalt trioxide quantum dot@carbon composite electrode material and a preparation method thereof. Background technique [0002] Supercapacitors have been widely used in automobiles and electronics due to their high energy density and power density, fast charge-discharge performance, long cycle life, and environmental friendliness. There are mainly three kinds of electrode materials currently used in supercapacitors: carbon materials, transition metal oxides and conductive polymers. Compared with carbon materials, fast and reversible redox reactions can occur between transition metal oxides and electrolytes, resulting in higher specific capacitance. Cobalt tetroxide is low in cost, environmentally friendly, and has a high theoretical specific capacity (3560F g -1 ), are considered as promising candidates for enhancing the energy density of supercapacitors. ...

AI Technical Summary

Problems solved by technology

[0004] In previous studies on cobalt tetroxide electrodes, high specific surface area carbon materials such as graphene can provide a large amount of dispersion space for cobalt salts, but its open planar structure is difficult to play a good role in restricting the agglomeration and growth of nanoparticles

In the common synthesis method, it is difficult to eliminate the hydrophobicity of the carbon material by liquid phase mixing, and the affinity between the composite interface is insufficient, so it is difficult to ensure that a large amount of cobalt ions dissolved in the solution will all enter the pores, resulting in the residual cobalt tetroxide outside the carbon material.

During the long-term charging and discharging process, its structural stability is difficult to be guaranteed, and the nanoparticles are easy to fall off from the surface of the carbon material, resulting in a sharp decline in electrochemical performance.

In addition, in the current cobalt tetroxide / carbon composite electrode materials, it is difficult to break through the size of cobalt tetroxide below 5nm, the active components inside the particles cannot contact the electrolyte, and it is difficult to maximize the electrochemical performance of cobalt tetroxide

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