LAUSR

Abstract Through electrodeposition, controlling hydrogen evolution reaction and selective electrochemical dealloying of copper from Ni Cu porous foam, highly nanoporous nickel and nickel oxide is fabricated on the copper surface. Electrochemically reduced graphene oxide (ERGO) is loaded on the Ni NiO foam as high-performance electrodes for supercapacitors through pulsed galvanostatic reduction of drop casted graphene oxide nanosheets at different duty cycles and frequencies. Surface morphology and composition of fabricated ERGO/Ni NiO foam composite electrodes are characterized using scanning electron microscopy (SEM), powder X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), Raman Spectroscopy. Electrochemical impedance spectroscopy (EIS) measurements, galvanostatic charge/discharge (GCD) and cyclic voltammetry (CV) are carried out to study the electrochemical behavior of ERGO/Ni NiO foam electrodes. From structural and electrochemical characterizations, optimized parameters for pulse duty cycle and frequency were found to be 10% and 1000 Hz, respectively. As a result, the ERGO/Ni NiO foam film (ic = −10 mA/cm2, f = 1000 Hz and DC = 10%) provides a specific capacitance of 2298 F/g in 1 M KOH at a current density of 1 A/g. Stability study of fabricated film represents a long cycling life up to 4000 cycles with 0.7% decay in specific capacitance at the high current density of 20 A/g in the potential range of 0–0.6 V vs. saturated calomel electrode (SCE).