Tailoring oriented TiO2 nanotube morphology for improved Li storage kinetics

We report on the syntheses of oriented TiO2 nanotube (NT) arrays having different geometries and the electrochemical properties as electrodes for lithium rechargeable batteries. The morphology of the NT arrays, which were prepared by electrochemical anodization of Ti foil, is investigated by scanning electron microscopy. X-ray diffraction analysis indicates that annealing the as-grown NT films at a temperature of 400 degrees C transforms them from an amorphous phase to anatase TiO2. Analyses of cyclic voltammograms indicate that there is significant capacitive Li+ storage associated with the NT surface in addition to the Li+ storage within the bulk material. The NT morphological parameters (e.g. pore diameter, wall thickness, and roughness factor) are found to have significant effects on the Li-ion insertion/extraction kinetics and the performance of the electrodes in lithium-ion batteries. (C) 2012 Elsevier Ltd. All rights reserved.