Mo-doped porous Co3O4 nanoflakes as an electrode with the enhanced capacitive contribution for asymmetric supercapacitor application

Cobalt oxide (Co3O4) electrode materials have tremendous properties for supercapacitors, such as being environmentally friendly, having a high surface area, being low cost, and having high theoretical specific capacitance (3560 Fg- 1). However, its poor electronic conductivity restricts the performance of the practical application. Doping transition metal ions into the host materials is an effective method to improve conductivity and enhance storage capacity. In this research work, we studied Mo-doped Co3O4 nanostructure electrodes synthesized using the electrodeposition technique. The integrated material samples were characterized by XRD, SEM with EDAX, XPS, FTIR, Raman spectra, UV-visible, and BET for their structure, morphology, composition, optical, and surface area properties. The 2 mM Mo-doped Co3O4 electrode exhibits excellent electrochemical pseudocapacitive properties. The optimized Mo2-doped Co3O4 shows a maximum specific capacitance of 1674 Fg-1 at 10 mA cm-2 current density in 1 M KOH electrolyte solution. Finally, the asymmetrical hybrid supercapacitor device (AsHScD) Mo2-Co3O4//rGO) demonstrates the highest power density of 159.0 KWKg-1 and maximum energy density of 13.80 WhKg-1 with a long-term stability of 95 % up to 2000 cycles. The Mo2-Co3O4 electrode is a promising candidate material for a charge-storage hybrid supercapacitor in an aqueous 1 M KOH electrolyte.