Fabrication Of Co₃O₄ Composite Electrode Materials And Its Electrochemical Performance Investigation

Supercapacitor is a new type of enviro nmentally friendly energy storage devices, are fast charge and discharge, able to work, high stability, high current discharge temperature limit narrow, good reliability, free maintenance, and the advantages of green enviro nmental protection, widely used in railway, electric power, electronics, communication, automobile, defense and other fields. Supercapacitor device performance fit and unfit quality directly depends on the selection of electrode materials, so that continuously improve the electrochemical performance of super capacitor electrode material is the focus of the research work at home and abroad In this paper, on the basis of the cobalt oxide electrode materials, by optimizing the preparation process parameters and the polypyrrole and cobalt nickel hydroxide electrode material and electrode material, compound modification, build a new type of composite electrode materials, eventually improve the electrochemical performance The main research work includes the following content:1. Foam nickel(NF) as the framework to carry out the conditions and performance of the process for preparing Co3O4 by hydrothermal method. By adjusting the reaction temperature, calcination temperature and other parameters, to explore the conditions of Co3O4 structure, morphology and electrochemical properties of law prepare Co3O4 electrode material having optimum microstructure and electrochemical properties of nickel foam as a follow-up to further study kernel-based composite electrodes. The results show that the effect of water temperature on the thermal reaction Co3O4 phase structure is more obvious, and the firing temperature on the microstructure significant effect Co3O4. In the hydrothermal reaction temperature of 120 ℃, generating phase single-phase cubic spinel Co3O4 electrode material. Co3O4 by thermal reaction at 120℃ and 250℃ calcined made with structural characteristics of nanowires at 1 A/g current density than the capacity of 863 F/g, and after 2,000 charge-discharge cycles of its specific capacity remained at 98%. Analyze the underlying mechanism should nanowire electrode material microstructure has the largest surface area, to the greatest extent promote charge transport between the electrodes and the electrolyte, reducing the electronic entry and prolapse of resistance and increase the cobalt oxide electrochemical performance.2. In the above structure made of nanowire electrode material Co3O4 foamed nickel-based, to carry out Co3O4 and properties of polypyrrole composite electrode material. Using a simple titration method composite oxide prepared Co3O4/Ppy composite electrode material, the amount of change in the doping polypyrrole composite electrode materials and electrochemical properties of the internal mechanism of the law. The results show that after Co3O4 composite polypyrrole, at 5 A/g current density ratio dropped from 708 F/g to 580 F/g. Visible did not raise its capacity by more than expected results after Co3O4 and polypyrrole composite electrode material, worsened the Co3O4 electrode electrochemical performance. Analysis of the reasons should be reunited polypyrrole covering the Co3O4, undermines its nanowire structures, and hinder the transfer rate of electrons, and ultimately reduce the electrochemical properties of the composites.3. By the 1 to prepare a nanowire structures Co3O4/Ppy to carry out 2 and properties of composite electrodes prepared Co3O4/NiCo(OH)2. First potentiostatic deposition techniques Co(OH)2 and Ni(OH)2 were mixed in the electrode material Co3O4 phase, XRD analysis showed that the product characteristic diffraction peaks coincide with the standard map shows really made core- shell Co3O4/NiCo(OH)2 composite electrodes. Electrochemical performance analysis showed that, Co3O4/NiCo(OH)2 composite electrodes capacitance can be increased compared to the pre-composite Co3O4 fold to 1710 F/g, and after 3,000 charge-discharge cycles of its specific capacity remained at 94% the above.4. To carry out preliminary performance rechargeable batteries and supercapacitors practical simulation study. Activated carbon as the positive electrode, with Co3O4/NiCo(OH)2 as the negative electrode material composite, asymmetric supercapacitors assembled, the specific capacity of up to 153 F/g, up to 1.6 V potential window. After a short time in the actual simulation which can charge for the LED light bulb and a small fan in the long run to provide power, showed a typical supercapacitor fast charge and slow release characteristics prove Co3O4/NiCo(OH)2 composite electrodes with more good potential commercial applications.