The effect of synthesis temperature on the properties of TiO2 (B) nanorods and its precursors as anode materials for lithium-ion batteries

In this work, we carried out a detailed research on the effect of synthesis temperature on the properties of TiO2 (B) nanorods and its hydrogen titanate precursors. At the initial stage, hydrogen titanates (HTOs) were synthesised at different temperatures (140 degrees C-180 degrees C). The HTO materials were then annealed at 400 degrees C for 2 h in the second-stage to produce TiO2 (B) nanorods. It is interesting to note that the pure anatase phase of TiO2 nanorods (TO140) was achieved from the HTO material (HTO140) prepared at 140 degrees C, while the TiO2 (B) nanorods were only formed from those synthesised at 160 degrees C (HTO160) and 180 degrees C (HTO180). In the evaluation of these materials as anodes for lithium ion batteries (LIBs), HTO140 showed better rate performance at higher current rates (500-1000 mAg(-1)). However, HTO160 and HTO180 displayed lower initial discharge capacities than that of their precursor (the commercial TO) at 200 mAg(-1). Addtionally, HTO160 exhibited the best stability with 71.5% retention after 100 cycles at 200 mAg(-1). Moreover, the annealed product of TO140 from HTO140 demonstrated the highest initial discharge capacity with a value of 164.3 mAhg(-1) at a current of 200 mAg(-1), which is corresponding to its low charge transfer resistance. However, TO160 showed a superior stability with 92.3% retained capacity after 100 cycles at 200 mAg(-1). Overall, 160 degrees C is the optimum temperature to synthesize TiO2 (B) nanorods, regarding to its good cycling stability and mild capacity as anode materials. The investigation showed that the synthesis temperature is a determining factor to producing either TiO2 (B) or anatase TiO2 nanorods, has an influence on the properties of the precursor as well as the TiO2 (B) as anode materials for LIBs.