A novel hybridized needle-like Co3O4/N-CNO composite for superior energy storage asymmetric supercapacitors

Abstract

The controlled growth of needle-like Co3O4 and composite formation with highly graphitic carbons such as N-CNOs is critically essential for obtaining high-performance energy storage supercapacitors. In this study, the needle-like Co3O4 and graphitic N-CNOs are synthesized by the simple solvothermal and pyrolysis methods, respectively. The Co3O4/N-CNO composite enhances the fast charge transfer by reducing ion diffusion. The Co3O4/N-CNO composite demonstrated an improved specific capacitance (3066 F g−1) than the needle-like structure of Co3O4 (2068 F g−1). The Co3O4/N-CNO composite exhibited very good rate capability and high capacitance retention of 82% at a high current density of 8 A g−1 meanwhile the Co3O4/N-CNO//AC ASC device shows high power and energy densities with capacitance retention of 78% and Coulombic efficiency of 100% over 2000 cycles. This attractive electrochemical performance of Co3O4/N-CNO composite makes it a favorable device for practical applications of supercapacitors.