Low temperature Hydrogen Reduction of High Surface Area Anatase and Anatase/β-TiO2 for High-Charging-Rate Batteries

There are several strategies to improve the electrochemical performance of TiO2 as negative electrode material for Li-ion batteries. Introducing oxygen vacancies through hydrogen reduction leads to an enhancement in electrical conductivity. However, this strategy does not improve the low lithium-ion mobility. Herein, we show that by decreasing the temperature of hydrogen annealing the improved lithium-ion mobility of high-surface-area TiO2 and beta-TiO2 can be combined with the enhanced electrical conductivity of oxygen deficiencies. An-nealing at only 275-300 degrees C in pure hydrogen atmosphere successfully creates oxygen vacancies in TiO2, as confirmed by UV/Vis spectroscopy, whereas the temperature is low enough to maintain a high specific surface area and prevent beta-to-anatase phase transformation. The hydrogen reduction of high-surface area anatase or anatase/beta-TiO2 at these temperatures leads to improvements in the performance, achieving charge capacities of 142 or 152 mAhg(-1) at 10C, respectively.