Rate characteristics of anatase TiO2 nanotubes and nanorods for lithium battery anode materials at room temperature

Abstract

Anatase Ti O2 nanotubes and nanorods were prepared by annealing mixed H2 Ti2 O5 H2 O and anatase Ti O2 nanotubes at 300 and 400°C, respectively. The first discharge capacities of anatase nanotubes and nanorods were 296 mAhg (Li0.88 Ti O2) and 215 mAhg (Li0.64 Ti O2), respectively. Irreversible capacity ratios were 14 and 15% for anatase nanotubes and nanorods, respectively. Capacity retention of the nanotubes was 81%, and that of the nanorods was 40% after 30 cycles. In contrast to nanotubes, the high rate performance of nanorods strongly depended on the electrode density of the electrode. Nanorods with 0.5 g cm3 (=12 mg cm2) showed 200 and 160 mAhg at 0.5 and 10 C rates, respectively. However, nanotubes showed no capacity decrease at 0.5 or 10 C under an electrode density of either 1 or 0.5 g cm3. Under 2 g cm3 (=31 mg cm2), nanotubes showed 245 and 185 mAhg at 0.5 and 2 C rates, respectively.