Walnut-like Porous Core/Shell TiO2 with Hybridized Phases Enabling Fast and Stable Lithium Storage.

TiO2 is a promising and safe anode material for lithium ion batteries (LIBs). However, its practical application has been plagued by its poor rate capability and cycling properties. Herein, we successfully demonstrate a novel structured TiO2 anode with excellent rate capability and ultralong cycle life. The TiO2 material reported here shows a walnut-like porous core/shell structure with hybridized anatase/amorphous phases. The effective synergy of the unique walnut-like porous core/shell structure, the phase hybridization with nanoscale coherent heterointerfaces, and the presence of minor carbon species endows the TiO2 material with superior lithium storage properties in terms of high capacity (∼177 mA h g-1 at 1 C, 1 C = 170 mA g-1), good rate capability (62 mA h g-1 at 100 C), and excellent cycling stability (∼83 mA h g-1 was retained over 10 000 cycles at 10 C with a capacity decay of 0.002% per cycle).