Anatase TiO2 Nanorods as Cathode Materials for Aluminum-Ion Batteries

In view of the practical deployment of Al-ion batteries for stationary energy storage, novel and cost-efficient cathodes consisting of earth-abundant chemical elements are imperative. Titanium dioxide TiO2 is an appealing candidate as a cathode material due to high natural reserves of the constituent elements as well as its nontoxicity and high chemical robustness. In this work, we assessed the potential of anatase TiO2 nanorods as a cathode material for Al-ion storage. This material delivers high capacities of 112–165 mAh g–1 at a current density of 50 mA g–1 in AlCl3/1-Ethyl-3-methylimidazolium chloride ionic liquid electrolyte of various acidity. The mechanism of aluminum intercalation into anatase TiO2 nanorods and the related crystal structure changes were assessed by density functional theory, ex situ X-ray photoelectron and energy-dispersive X-ray spectroscopies.