Reversible Mg2+ insertion/deinsertion of rutile TiO2 in noncorrosive electrolytes

Abstract Single-crystal rutile TiO2 with a spindle morphology was investigated as a negative electrode material for Mg-ion batteries. In the electrolyte with ethylene carbonate and diethyl carbonate typically used for Li-ion batteries, the rutile TiO2 exhibited reversible capacities of 163 and 94 mA h g−1 at the first cycle and 50th cycle, respectively. The spindle structure developed in the c-axis direction should contribute easier Mg2+ diffusion inside the structure to improve utilization of the active material.