Porous NiO/C Nanocomposites as Electrode Material for Electrochemical Supercapacitors

NiO/C nanocomposites were synthesized at different calcination temperatures using starch as the stabilizing agent. The NiO/C nanocomposites were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The samples calcined at 500 °C exhibit a highly porous nature. Electrochemical investigations of NiO/C were carried out using cyclic voltammetry, chronopotentiometry, and electrochemical impedance spectroscopy. NiO/C-5 shows excellent electrochemical performance compared to NiO/C-4 and NiO/C-6. The NiO/C-5 electrode exhibits a specific capacitance value of 644 F g<sup>–1</sup> at a scan rate of 2 mV s<sup>–1</sup>. The charge transfer resistance is 0.59 Ω for the NiO/C-5 electrode. This NiO/C-5 appears to be a promising electrode material for supercapacitor applications.