Rate Characteristics of Anatase TiO[sub 2] 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.