Formation of CoO-NiO Nanoparticles on Nitrogen Doped Porous Carbon as High Performance Supercapacitor Electrode

Doping porous carbon with transition metal oxides is highly desirable for high performance supercapacitors due to their synergistic effect. Herein, a highly dispersed CoO-NiO nanoparticle doped porous carbon (CoO-NiO@ZIF-C) was prepared by pyrolysis of Ni2+ and Co2+ ions impregnated ZIF-8. The metal nanoparticles catalyze the formation of graphitic carbon, while the N-doped carbon substrate confines the nanoparticles during the process. The resulted nanocomposite demonstrates excellent capacitive performance, which delivered a specific capacitance of 552.3 F g-1 at current density of 1 A g-1. Moreover, an asymmetric supercapacitor was successfully assembled using CoO-NiO@ZIF-C as positive electrode and reduced graphene oxide as the negative electrode. The two-electrode cell delivered a maximum energy density of 43.5 Wh kg-1 at a power density of 1892.1 W kg-1 with good stability.