Perforated Co3O4 nanosheets as high-performing supercapacitor material

Abstract While cobalt oxide (Co3O4) is a promising material to be used in electrical energy storage systems, its full potential remains to be tapped presumably due to limited porous surface (small surface area) and high electrical resistance. In this work, the Co3O4 is prepared in the form of perforated nanosheets using hydrothermal synthesis method. After the detailed characterization of structure, phase purity, surface morphology, surface area and pore-size distribution, the potential of the as-prepared Co3O4 is evaluated as electrode materials for supercapacitor. The perforated Co3O4 nanosheets exhibited excellent specific capacitance performance of 1455.64 F g−1 at 1.0 A g−1 in 3.0 M KOH electrolyte solution. The fabricated asymmetric device showed an excellent (94.10%) retention after 2000 cycles suggesting high chemical stability because of upright standing perforated Co3O4 nanosheets. The Co3O4//Co3O4 symmetric device exhibited the energy density of 22.51 Wh kg−1 and maximum power density of 311.68 W kg−1 at the current density of 1 A g−1, reflecting its industrial potential. In addition, the fabricated device showed excellent chemical and cyclic stability with 82.52% after 2000 cycles at current density of 5 A g−1. The present work demonstrates the capabilities of the perforated Co3O4 nanosheets morphology with admirable half-cell and device performance.