Simulation and fabrication of titanium dioxide thin films for supercapacitor electrode applications

Abstract

Nanostructured thin-film electrode materials are proposed for supercapacitors due to their outstanding performance over bulk materials. In this work, we fabricated a TiO2 nanotube film over a titanium foil using a top-down approach for supercapacitor electrodes. We noticed that the fabricated nanotubes are uniform and well aligned, confirmed by FESEM; the TiO2 nanotube parameters were further simulated using COMSOL Multiphysics. Simulations show an areal capacitance of 1.19393 pF/cm2 with oxidation and reduction peak currents of 6.18921×10[Formula: see text] A and −6.0320×10[Formula: see text] A, respectively, at 10 mV/s scan rate. The as-prepared nanotubes show a poor areal capacitance of 1.0193 F/cm2, which is improved to 12.8764 F/cm2 at a scan rate of 10 mV/s, that is approximately 12.63 times with oxidation and reduction peak currents of 0.129 mA/cm2 and −0.105 mA/cm2, respectively, by performing an electrochemical etching. Further, the surface roughness of both as-prepared and etched samples is studied to comment on their surface area changes. The effect of the etched sample is studied, compared and validated with simulation, which reveals that the etched TiO2 nanotubes thin-film sample shows considerable similarity with the simulation results.