Synthesis of uniform layered protonated titanate hierarchical spheres and their transformation to anatase TiO ₂ for lithium-ion batteries

Layered protonated titanates (LPTs), a class of interesting inorganic layered materials, have been widely studied because of their many unique properties and their use as precursors to many important TiO ₂-based functional materials. In this work, we have developed a facile solvothermal method to synthesize hierarchical spheres (HSs) assembled from ultrathin LPT nanosheets. These LPT hierarchical spheres possess a porous structure with a large specific surface area and high stability. Importantly, the size and morphology of the LPT hierarchical spheres are easily tunable by varying the synthesis conditions. These LPT HSs can be easily converted to anatase TiO ₂ HSs without significant structural alteration. Depending on the calcination atmosphere of air or N ₂, pure anatase TiO ₂ HSs or carbon-supported TiO ₂ HSs, respectively, can be obtained. Remarkably, both types of TiO ₂ HSs manifest excellent cyclability and rate capability when evaluated as anode materials for high-power lithium-ion batteries.