Preparation, Characterization and Study of Charge Storage Ability of Nanostructured Co3O4

Research has revealed that sheet- or plate-like structures can very well improve the supercapacitive behavior of Co3O4 as the electrode material [1,2]. These nanostructures possess large material–electrolyte interface areas, increased electrolyte penetration into the electroactive materials, large inter-sheet spacings for the rapid ions transport, large surface areas for better electrochemical reactions, and high utilization of the electrode materials. In this research, cathodic electrodeposition followed by heat-treatment, was applied as a powerful technique for the preparation of nanostructured Co3O4 with particular characteristics. In this two-step route, cobalt hydroxide (Co(OH)2) is first electrodeposited via pulse base (OH–) electrogeneration from a nitrate bath and the product of this step was heat-treated under a proper atmosphere and temperature to yield cobalt oxide. The structural and morphological evaluations by XRD and SEM revealed that the prepared oxide has crystalline Co3O4 structure (Fig. 1a) with plate morphology (Fig. 1b). The supercapacitive performance of the Co3O4 was also studied by cyclic voltammetry (CV) and charge-discharge cycling as shown in Figs. 1c and d. The results showed that the prepared Co3O4 nanoplates are capable to deliver specific capacitance as high as 565 F g–1 at the scan rate of 2 mV s–1) and excellent long-term cycling stability of 89.1% capacity retention after 3000 cycling. 239