Unprecedented and highly stable lithium storage capacity of (001) faceted nanosheet-constructed hierarchically porous TiO/rGO hybrid architecture for high-performance Li-ion batteries.

Active crystal facets can generate special properties for various applications. Herein, we report a (001) faceted nanosheet-constructed hierarchically porous TiO/rGO hybrid architecture with unprecedented and highly stable lithium storage performance. Density functional theory calculations show that the (001) faceted TiO nanosheets enable enhanced reaction kinetics by reinforcing their contact with the electrolyte and shortening the path length of Li diffusion and insertion-extraction. The reduced graphene oxide (rGO) nanosheets in this TiO/rGO hybrid largely improve charge transport, while the porous hierarchy at different length scales favors continuous electrolyte permeation and accommodates volume change. This hierarchically porous TiO/rGO hybrid anode material demonstrates an excellent reversible capacity of 250 mAh g at 1 C (1 C = 335 mA g) at a voltage window of 1.0-3.0 V. Even after 1000 cycles at 5 C and 500 cycles at 10 C, the anode retains exceptional and stable capacities of 176 and 160 mAh g, respectively. Moreover, the formed LiTiO nanodots facilitate reversed Li insertion-extraction during the cycling process. The above results indicate the best performance of TiO-based materials as anodes for lithium-ion batteries reported in the literature.