Synthesis and Characterization of Tin Titanate Nanotubes : Precursors for Nanoparticulate Sn-Doped TiO₂ Anodes with Synergistically Improved Electrochemical Performance

The synthesis of tin-titanate nanotubes (Sn-titanate) by reacting hydrogen titanate (H-titanate) with a tin salt through ion adsorption-incorporation is reported. The interactions between tin(II) ions and H-titanate are thoroughly investigated. Tin ions can be easily adsorbed by H-titanate, owing to its large surface area and lattice spacing, and the negatively charged layered structures. With Sn-titanate nanotubes as precursors, Sn-doped TiO₂ nanoparticles are prepared by annealing and are investigated as anode materials in lithium-ion batteries, which show much enhanced capacity and rate capability. Such improved electrochemical properties of Sn-doped TiO₂ benefit from structural characteristics such as the small size of the constituent nanoparticles, high crystallinity, and uniform tin doping. This synthetic strategy towards Sn-doped TiO₂ anode materials, thus offers the synergistic effect of combining the advantages of TiO₂ (cycle life and rate) and SnO₂ (high capacity).