Carbon-supported ultra-thin anatase TiO2 nanosheets for fast reversible lithium storage

This work reports a two-step method to synthesize carbon-supported ultrathin anatase TiO2 nanosheets (C-TiO2 NSs). Three samples with distinct structures were prepared via the assembly of these unique C-TiO2 NSs, including solid TiO2 hierarchical spheres and their hollow counterparts, as well as randomly-oriented C-TiO2 NSs. Specifically, the organic additive (diethylenetriamine) serves as both the capping agent during the initial solvothermal synthesis that stabilizes the (001) facets of anatase TiO2 and also the carbon source during the subsequent carbonization process. When evaluated for electrochemical lithium storage, all three samples assembled from carbon-supported anatase TiO2 NSs exhibit high reversible capacities with superior cyclic capacity retention at a high current rate. This enhanced lithium storage performance could be attributed to the ultrathin NS structure allowing efficient Li+ ion diffusion, as well as the effective nanocarbon support granting better structural stability. These findings suggest that carbon-supported TiO2 NSs may be used as a promising anode material for high-power lithium-ion batteries.