Facile hydrothermal synthesis and electrochemical investigation of a free-standing cobalt oxide hierarchical nanostructure electrode on a porous carbon structure as an efficient supercapacitor

In the current work, we report the binder-free hydrothermal one-pot synthesis of a cobalt oxide hierarchical nanostructure (Co3O4-HNS) onto a highly conductive carbon fiber substrate (CFS/Co3O4-HNS) as an efficient electrode for energy storage devices. The fabricated electrode and synthesized Co3O4-HNS were structurally characterized using SEM, EDAX, XRD, and FTIR techniques. Electrochemical characterization of the fabricated CFS/Co3O4-HNS electrode was also performed and showed that the electrical double-layer capacitance and pseudo-capacitance mechanisms both play roles in the charge storage of the CFS/Co3O4-HNS electrode. The obtained results exhibited the electrochemical-specific capacitance of 715 F/g at a current density of 3 A/g for the CFE/Co3O4-HNS electrode. The fabricated electrode remains at 96% of its initial capacitance after 3000 cycles, showing the excellent cyclability of the fabricated CFS/Co3O4-HNS electrode. These results paved the way for using the proposed facile, one-pot synthesized CFE/Co3O4-HNS as an efficient electrode for use in electrochemical energy storage devices.