Defect‐rich bronze titanium dioxide ultrathin nanosheets supported on carbon nanotubes for enhanced lithium‐ion storages

Bronze titanium dioxide (TiO2[B]) is widely used to improve lithium-ion storage performances owing to their open crystal structure, pseudocapacitance effect, and high theoretical specific capacity. However, the reported storage performances of TiO2(B) for lithium-ion batteries (LIBs) are not ideal, due to the sluggish lithium-ion diffusivity and poor electronic conductivity. Herein, mesoporous TiO2(B) ultrathin nanosheets with rich oxygen vacancies supported on carbon nanotubes (TiO2[B]-CNTs) were constructed to enhance lithium-ion storages via a simple solvothermal method combined with an annealing process under Ar atmosphere. The CNTs substrate in situ induces the orderly growth of mesoporous TiO2(B) ultrathin nanosheets with ~5 nm thinness and rich oxygen vacancies into a stabilized microstructure, which not only prevent aggregation of nanosheets, but also ensure effective exposure surface, as well as enhance the electronic conductivity. As-obtained TiO2(B)-CNTs electrodes in LIBs at 0.1 A g−1 after 100 cycles still show superior cycling performances with ~280 mAh g−1. Specifically, the TiO2(B)-CNTs electrodes maintain good long-term cycling performances. The specific capacities reached ~230 mAh g−1 at 0.5 A g−1in the 700th cycle, and ~150 mAh g−1 at 2.0 A g−1 in the 1000th cycle, respectively.