Conjugated NiO‐ZnO/GO nanocomposite powder for applications in supercapacitor electrodes material

Summary The nanocomposite of NiO‐ZnO/graphene oxide (GO) was synthesized for applications in supercapacitor electrodes material. GO was produced using the modified Hummers' method, and the nanocomposite of NiO‐ZnO/GO was synthesized using the co‐precipitation method. Thin films of nanocomposite powder were deposited on quartzite (glass) and fluorine‐doped tin oxide substrates by a drop casting technique. X‐ray diffraction revealed the crystallographic information of NiO‐ZnO/GO nanocomposites. The surface morphology and elemental composition were studied using a scanning electron microscopy and energy‐dispersive X‐ray spectroscopy, respectively. The electrochemical properties were examined using cyclic voltammetry in a 1.0 M solution of Na2SO4 electrolyte with a three‐electrode system. Moreover, the NiO‐ZnO/GO binary metal oxides nanocomposite based electrodes fabricated for supercapacitor delivered a high specific capacitance of 1690 F g−1 for 1:1/GO sample at a scan rate of 10 mV s−1 and has excellent conductivity due to reduced band gap energy range of 1.52‐1.79 eV and with electrodes resistance of 0.02 Ω. The absence of semicircle in the Nyquist plot denotes low charge transfer resistance of the electrodes. The highest energy densities obtained for 1:1/GO and 2:1/GO are 192 and 148 Wh kg−1, respectively, while the highest power density obtained for 1:1/GO and 2:1/GO are 8.46 and 7.42 W kg−1, respectively. Our study paves way for a facile, affordable, nontoxic, and fast way to synthesis binary transition metal oxides/GO‐based electrodes material for high‐performance supercapacitor.