Carbon-supported ultra-thin anatase TiO2nanosheets for fast reversible lithium storage

Abstract

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.