Hexagonal sheets of Co₃O₄ and Co₃O₄-Ag for high-performance electrochemical supercapacitors

Hexagonal sheets of Co₃O₄ on nickel foam were synthesized by a facile, economical, scalable, and one pot hydrothermal method for supercapacitor studies. The electrical conductivity and catalytic activity were enhanced through the decoration of Co₃O₄ by silver (Ag) nanoparticles using a simple chemical approach. The hexagonal sheets served as an excellent backbone together with the Ag nanoparticles, which gave the composites a superior specific capacitance of 958 F g⁻¹ and an energy density of 0.203 kWh kg⁻¹. The electrode exhibited excellent cycling stability with a capacitance retention of 104% after the initial 1000 CV cycles with a maximum specific capacitance 996 F g⁻¹.