Highly Ordered TiO2 Microcones with High Rate Performance for Enhanced Lithium-Ion Storage.

The perpendicularly oriented anatase TiO2 microcones for Li-ion battery application were synthesized via anodization of a Ti foil in aqueous HF + H3PO4 solution. The TiO2 microcones exhibited a high active surface area with a hollow core depending on applied voltage and reaction time, confirmed by SEM, XRD and TEM with EDS mapping. Li insertion/desertion into TiO2 microcones was evaluated for the first time in half-cell configuration in terms of various current density and long-term cyclability. The electrochemical experiments demonstrated that the as-prepared TiO2 microcones as anode material exhibited 3 times higher capacity as compared with TiO2 nanotubular structures, excellent rate performance (0.054 mAhcm(-2) even at 50 C) and reliable capacity retention during 500 cycles, which was attributed to facile diffusion of Li-ions induced in hollow anatase TiO2 microcones structure with multilayered nanofragment.