Porous Graphene-NiCo2O4 Nanorod Hybrid Composite as High Performance Supercapacitor Electrode Material
Template free low temperature solvothermal synthesis of high capacitive porous graphene-NiCo2O4 nanorod composites has been carried out. Solvothermal synthesis, followed by calcination in air led to development of highly porous hybrid nanocomposite which acts as a buffering channel for fast ion diffusion and provides robust mechanical strength. Advantages of using porous graphene to enhance the capacitance of the material were studied theoretically using first principles calculations. High capacitance values of 1533 F g-1 at a scan rate of 5 mV s-1 and 1684 F g-1 at a current density of 1 A g-1 are obtained from cyclic voltammetry data and galvanostatic charge discharge data, respectively. The electrode material possesses good rate capability with retention of 94 % of its initial capacitance even after 10000 charge-discharge cycles at a current density of 8 A g-1 in 2 M KOH electrolyte. The fabricated supercapacitor exhibited high energy density of 45.3 Wh kg-1 and high power density of 17843.5 W kg-1 due to the synergistic effect of the composite components. The enhanced electrochemical function of the composite makes it a potential candidate for supercapacitor application and future studies.