Self-organized anodic titanium oxide microcones for Li-ion battery application

초록

Titanium oxides have been studied for various applications such as dye-sensitized solar cells, water splitting electrodes, photocatalysts, gas sensors and electrochemical energy storages because of chemically stability and excellent (photo-) catalytic properties[1-4]. The enlargement of surface area is one of important routes to enhance titanium oxide’s physical properties for various applications. Thus, titanium oxides with various morphologies such as nanorods, nanotubes, nanowires and so on have been produced by several research groups[5-7]. In this study, we demonstrate that the self-organization of titanium oxide microcones can be successfully prepared by anodization under specific electrochemical conditions. In detail, the titanium oxide microcones are obtained by anodization at 45-75 V, whereas a barrier type or flower like morphology is synthesized at higher or lower than the optimized voltage. The prepared microcones with a height of more than 8.74 µm and a diameter of 9.1 µm is revealed as TiO2 anatase phase, even though no heat treatment is done. The titanium oxide microcones are applied to anode for Li-ion batteries. Electrochemical studies are performed to evaluate the battery capacity. The charge/discharge capacity of TiO2 microcones is higher than that of TiO2 nanotubes, which is attributed to easy mass-transfer of Li ions in the protruding microcone structure.