Unprecedented and highly stable lithium storage capacity of (001) faceted nanosheet-constructed hierarchically porous TiO2/rGO hybrid architecture for high-performance Li-ion batteries

Abstract

Active crystal facets can generate special properties for various applications. Herein, we report a (001) faceted nanosheet-constructed hierarchically porous TiO₂/rGO hybrid architecture with unprecedented and highly stable lithium storage performance. Density functional theory calculations show that the (001) faceted TiO₂ 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 TiO₂/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 TiO₂/rGO hybrid anode material demonstrates an excellent reversible capacity of 250 mAh g^-1 at 1 C (1 C = 335 mA g^-1) 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^-1, respectively. Moreover, the formed Li₂Ti₂O₄ nanodots facilitate reversed Li⁺ insertion-extraction during the cycling process. The above results indicate the best performance of TiO₂-based materials as anodes for lithium-ion batteries reported in the literature.