Electrochemical characteristics of cobalt oxide electrode for supercapacitor

Fine cobalt oxide xerogel powder was prepared by a unique solution chemistry associated with a sol-gel process. Investigation of effect of thermal treatment on the crystalinity, particle structure, and corresponding electrochemical properties of the resulting xerogel revealed that amorphous structure of Co(OH)(2) remained up to 160 degreesC. With an increase in the temperature above 200 degreesC, both the surface area and pore volume decreased sharply, because the amorphous Co(OH)(2) was converted to form CoO and was subsequently oxidized to crystalline Co3O4. In addition, the changes in the crystallinity, and particle structure were accompanied to the chemical reaction. All things were found to influence the electrochemical properties of the resulting xerogels. A maximum capacitance of 192 F/g was obtained for the CoO. Xerogel calcined at 150 degreesC, which possessed highest values in both surface area and pore volume. To increase capacitance, we added PVA as a dispenser. It is better in terms of capacitance, and then it was carried out capacitance changes of CoOx to acquire stability in cycle tester during 1000 cycle, it shows 450 F/g in average.