Preparation, Characterization and Study of Charge Storage Ability ofNanostructured Co3O4

Research has revealed that sheet- or plate-like structures can very well improve thesupercapacitive behavior of Co3O4 as the electrode material [1,2]. These nanostructures possesslarge material–electrolyte interface areas, increased electrolyte penetration into the electroactivematerials, large inter-sheet spacings for the rapid ions transport, large surface areas for betterelectrochemical reactions, and high utilization of the electrode materials. In this research,cathodic electrodeposition followed by heat-treatment, was applied as a powerful technique forthe 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 froma nitrate bath and the product of this step was heat-treated under a proper atmosphere andtemperature to yield cobalt oxide. The structural and morphological evaluations by XRD andSEM revealed that the prepared oxide has crystalline Co3O4 structure (Fig. 1a) with platemorphology (Fig. 1b). The supercapacitive performance of the Co3O4 was also studied by cyclicvoltammetry (CV) and charge-discharge cycling as shown in Figs. 1c and d. The results showedthat the prepared Co3O4 nanoplates are capable to deliver specific capacitance as high as 565 Fg–1 at the scan rate of 2 mV s–1) and excellent long-term cycling stability of 89.1% capacityretention after 3000 cycling.

Keywords:

Co3O4 , Nano-plates , Pulse Electrosynthesis , Heat-treatment , Supercapacitiveperformance