The potential for low cost, environmentally friendly and high rate energy storage has led to the study of anatase-TiO₂ as an electrode material in aqueous Al3+ electrolytes. This paper describes the improved performance from an electrochemically treated composite TiO₂ electrode for use in aqueous Al-ion batteries. After application of the cathodic electrochemical treatment in 1 mol/dm³ KOH, Mott⁻Schottky analysis showed the treated electrode as having an increased electron density and an altered open circuit potential, which remained stable throughout cycling. The cathodic treatment also resulted in a change in colour of TiO₂. Treated-TiO₂ demonstrated improved capacity, coulombic efficiency and stability when galvanostatically cycled in 1 mol·dm-3AlCl₃/1 mol·dm-3 KCl. A treated-TiO₂ electrode produced a capacity of 15.3 mA·h·g-1 with 99.95% coulombic efficiency at the high specific current of 10 A/g. Additionally, X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy were employed to elucidate the origin of this improved performance.
Keywords: aqueous Al-ion; battery; electrochemical treatment; high-rate; titanium dioxide.