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

Abstract

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).