High surface area TiO2 nanospheres as a high-rate anode material for aqueous aluminium-ion batteries

Aluminium-ion batteries are promising electrochemical energy storage systems in replacement of Li-ion batteries owing to the low cost, non-toxicity, safety and three-electron transfer nature of Al-intercalation process. Anatase titanium dioxide has been suggested as a potential anode material for aqueous Al-ion batteries. In this work, TiO2 nanospheres (TiO2-NSs) with highly mesoporous morphology and large specific surface area (179.9 m2 g− 1) were synthesized via hydrolysis of titanium glycolate precursor and subsequent hydrothermal treatment and calcination in an argon atmosphere. The structure and morphology of the prepared TiO2-NSs were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and nitrogen adsorption-desorption. The high surface area TiO2-NSs provide large electrode/electrolyte interface and good electrolyte-holding characteristic, leading to shorten the diffusion path of electrons and ions to the active material, which results in the better high-rate performance. The TiO2-NSs anode exhibited a high initial discharge capacity of 183 mAh g− 1 at a current rate of 0.15 C and a superior rate performance with a capacity of 108 mAh g− 1 even at a discharge current rate of 6.0 C, which are much higher than those of TiO2-P25 electrode.