Electrodeposition of zinc and reduced graphene oxide on porous nickel electrodes for high performance supercapacitors

Electrochemical properties of porous nickel (Ni) foam, electrodeposited zinc (Zn) on Ni foam (Ni–Zn) and electrodeposited reduced graphene oxide (rGO) on Ni–Zn foam electrodes (Ni–Zn-rGO) in 6 M KOH electrolyte were investigated. Cyclic voltammetry (CV) and galvanostatic charge–discharge cycling (GCD) techniques were used to carry out the redox interactions, and cycling capacitive properties of the electrodes in KOH solution. Platinum (Pt) and gold (Au) foil were used as a counter electrode and the current collector in the electrochemical measurements, respectively. The specific capacitances of the electrodes were found from the GCD measurements as 155, 722 and 1820 F/g for Ni, Ni–Zn and Ni–Zn/rGO electrodes at the current density of 1 A/g, respectively. Scanning electron microscope (SEM) images of the three electrodes were also taken into account to associate all the electrochemical measurements. These results clearly show that specific capacitance values highly increased after the deposition of Zn and rGO to Ni electrode.