Electrochemical Characterization of Electrodeposited Ni–Cu Foams and Their Application as Electrodes for Supercapacitors

Nanoporous nickel–copper metallic foams were electrodeposited using the Dynamic Hydrogen Bubble Template (DHBT) technique. The effect of deposition parameters (applied current density and deposition time) on surface morphology of the obtained layers was studied with the aid of SEM. The Ni–Cu electrodeposited layers were characterized by a porous dendritic structure. According to EDX analysis, increasing both the deposition time and applied current density leads to an increase in the Ni content in the nano-foams. These foams were tested as electrodes for supercapacitors in 1 M KOH solutions. From potentiodynamic polarization test, the corrosion rate was accelerated when increasing the deposition time up to 150 s as well as the deposition current density up to 1.8 A/cm2. The electrochemical behavior of the material was studied by cyclic voltammetry aiming at its application as positive electrodes for supercapacitors, using 1 M KOH solution. From cyclic voltammetry, the increase in applied current density and the deposition time leads to an increase in the current density and total charge measured by cyclic voltammetry, having a beneficial effect on the electrochemical activity of the Ni–Cu films. The highest forward current peak was obtained for nickel–copper foams deposited at 2 A/cm2 for 150 s. From the EIS test, the polarization resistance (Rp) decreased when increasing the current density as well as electrodeposition time. The lowest polarization resistance was recorded for porous Ni–Cu layers electrodeposited at 2 A/cm2 for 150 s, indicating high electrochemical activity of this layers (35.02% Cu) as electrodes for supercapacitors.