TiO2 nanotubes grown on graphene sheets as advanced anode materials for high rate lithium ion batteries

Abstract

Here, we propose a unique architecture based on directly growing TiO₂ nanotubes on graphene sheets. This work establishes the benefits of combining nanotubular TiO₂ with conductive graphene to achieve a significant enhancement in capacitive energy storage. The TiO₂ nanotubes possess a porous structure and a higher surface area compared with its bulk material. The graphene sheets play an important role in the conductive substrate for charge collection. In the preparation process, amorphous TiO₂ colloids coated on graphene oxide (GO) sheets serve as the seeds to realize the growth of nanotubes, and ensure the robust contact between graphene and TiO₂ nanotubes to benefit charge transfer. When used as anodes for lithium ion batteries, the graphene–TiO₂ nanotubes (Gr–TNTs) manifest excellent rate capability and cycling performance, indicating that the nanotubes, graphene and their synergistic effect can prompt fast charge transfer in such a composite structure.