Enhanced Electrochemical Properties of Fe Doped TiO₂ Nanotubes for Supercapacitor Application

To obtain high power density, good capacitance, and improved energy density, the choice of substrate for supercapacitor fabrication is essential. Ti0 <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> nanotube arrays (T - NTs) are excellent semiconductor substrates due to their attractive properties such as large surface to volume ratio, chemically stable, less cost, environmental friendliness, and low toxicity. However, T-NTs alone possess low conductivity and show low specific capacitance. In the present work, F e-doped Ti0 <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> nanotubes were made using a very simple, easy, one-step electrochemical anodization process, and the performance was thoroughly characterized. Scanning electron microscopy was used to characterized the structural morphology of the nanostructure and its elemental composition was confirmed by energy dispersive X-ray spectroscopy. The doped substrate showed significantly enhanced electrochemical properties toward high -performance energy storage application with 38 times higher specific capacitance than that of plain T -NTs at 0.1 mA/cm2 current density. Additionally, at a power density of 0.05 m W/cm 2 the modified substrate demonstrated an excellent energy density of 2.61 μ Wh/cm 2 . The superior performances of the doped nanotube were accounted due to higher conductivity and improved charge transport rate at the electrode-electrolyte interface.