Süperkapasitör performansında çeşitli parametrelerin analizi

Transition metal oxides with enhanced electrochemical performance are points of interest in the fabrication of high efficient electrodes for supercapacitors. Therefore, in this study, our main purpose is to increase the conductivity and the effective surface area of the electrode composed of nickel-cobalt oxide (NCO) which enables to ease the mass diffusion and electron transport. With this aim, the nanosheets of NCO and NCO-reduced graphene oxide (NCO-RGO) hybrids were produced on nickel-foam substrate by a using facile one-step electrodeposition technique which was first performed. The hybrids of NCO-RGO were simultaneously prepared by the electrodeposition and reduction of GO and NCO, leading to a decrease in the total mass of active material on the electrode surface. The NCO-RGO hybrids were further deposited on the nickel-foam without using any binder; thus, it was avoided to decay in conductivity owing to the resistance of binder. After the optimizing of the number of coating layers, the optimization of GO amounts in the electrolyte comprised of equal moles of nickel and cobalt precursors was employed. Finally, NCO-RGO hybrids were fabricated at different nickel and cobalt molar ratios to determine the best performance. Electrochemical measurements confirmed that the specific capacitance and cycling stability of as-obtained electrodes were remarkably enhanced in the presence of RGO in the structure. The NCO-RGO hybrid which was fabricated from the electrolyte solution involving 0.25 mg of GO, exhibited a quite high specific capacitance as well as extraordinary cycling stability compared to NCO. Furthermore, the results indicated that with the increase in nickel content up to a certain rate, the specific capacitance was considerably increased. Out of all the prepared samples, the NCO-RGO hybrids possessed the highest specific capacitance of 1916.5 F/g at 1 A/g with extraordinary retention of 95.6% at a high current density of 10 A/g even after 3000 charge/discharge cycles. Additionally, NCO-RGO hybrids exhibited a high energy density of 53.90 Wh/kg at the power density of 235 W/kg and remained 41.20 Wh/kg at a high power density of 7500 W/kg, implying the attractive rate capability of these materials. As a result of this study, the NCO-RGO nanosheets having remarkable electrochemical performance have a potential as a promising facile and binder-free electrode for supercapacitor applications in the future.