Dual Functional Nanostructured Nickel Electrodes on Anodic Alumina for Energy Storage Applications.

This study presents a novel approach for fabricating nickel-based nanorod electrodes with dual electrochemical functionality, bridging supercapacitive and faradaic applications. Using nanoporous anodic alumina (NAA) templates and a pulsed electrodeposition technique, two distinct electrode configurations were engineered from a single presubstrate: nickel nanorods in NAA with partially dissolved pore walls (Ni-NR@NAA) and free-standing nickel nanorods after NAA removal and Ni redeposition (Ni-R-NR@NAA). Structural analysis via field-emission scanning electron microscopy (FESEM) confirmed the uniformity and integrity of the nanorods, while their electrochemical performance was evaluated by cyclic voltammetry (CV). The Ni-NR@NAA electrodes demonstrated the pseudocapacitive performance, achieving a capacitance per unit area of 104 mFcm, which is nearly seven times higher than flat nickel electrodes, attributed to the enhanced active surface area and efficient ion transport. Specific capacitance can reach up to 60 Fg at low scan rates. In contrast, the Ni-R-NR@NAA electrodes exhibited predominantly capacitive behavior with reduced redox activity due to structural modifications. These results emphasize the critical role of nanostructural design in tuning the electrochemical performance, offering a versatile platform for advanced energy storage devices capable of dual supercapacitive and faradaic functionality.