g-C₃N₄/CuO and g-C₃N₄/Co₃O₄ nanohybrid structures as efficient electrode materials in symmetric supercapacitors

Metal oxide dispersed graphitic carbon nitride hybrid nanocomposites (g-C₃N₄/CuO and g-C₃N₄/Co₃O₄) were prepared via a direct precipitation method. The materials were used as an electrode material in symmetric supercapacitors. The g-C₃N₄/Co₃O₄ electrode based device exhibited a specific capacitance of 201 F g^-1 which is substantially higher than those using g-C₃N₄/CuO (95 F g^-1) and bare g-C₃N₄ electrodes (72 F g^-1). At a constant power density of 1 kW kg^-1, the energy density given by g-C₃N₄/Co₃O₄ and g-C₃N₄/CuO devices is 27.9 W h kg^-1 and 13.2 W h kg^-1 respectively. The enhancement of the electrochemical performance in the hybrid material is attributed to the pseudo capacitive nature of the metal oxide nanoparticles incorporated in the g-C₃N₄ matrix.