Oxygen-Deficient Blue TiO2 for Ultrastable and Fast Lithium Storage

Developing a titanium dioxide (TiO2)-based anode with superior high-rate capability and long-term cycling stability is important for efficient energy storage. Herein, a simple one-step approach for fabricating blue TiO2 nanoparticles with oxygen vacancies is reported. Oxygen vacancies can enlarge lattice spaces, lower charge transfer resistance, and provide more active sites in TiO2 lattices. As a result, this blue TiO2 electrode exhibits a highly reversible capacity of 50 mAh g−1 at 100 C (16 800 mA g−1) even after 10 000 cycles, which is attributable to the combination of surface capacitive process and remarkable diffusion-controlled insertion revealed by the kinetic analysis. The strategy of employing oxygen-deficient nanoparticles may be extended to the design of other robust semiconductor materials as electrodes for energy storage.