Supercapacitive performance of 3D-cobalt oxide (Co3O4) nanowires grown onto anodized stainless-steel substrate: Effect of anodization time

Abstract

3D-Co3O4 nanowires were grown on anodized stainless steel (SSA) using a simple hydrothermal technique, with SSA as a cost-effective porous substrate. The originality of this work is to enhance surface activity and material adhesion by anodizing stainless steel (SS). After growth, the nanowires were thermally treated at 400 °C for 2 h. By varying the SS anodization time from 0 to 900s, changes in the structural, morphological, and electrochemical properties of Co3O4 were observed. XRD analysis confirmed the polycrystalline nature of Co3O4 with a face-centered cubic phase. SEM imaging showed noticeable changes in density and surface roughness. Supercapacitive properties were evaluated using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy (EIS) techniques, with SSANWs-300 exhibiting the highest specific capacitance of 529 Fg-1. Dunn’s method was used to analyze the contribution of capacitive and diffusive mechanisms to charge storage. EIS results indicated excellent electronic conductivity. The study suggests that SSANWs-300 holds promise for energy storage applications.