Annealing Temperature Effects of TiO2 Nanofiber Anodes for the Rechargeable Lithium Ion Batteries

TiO2 nanofibers (TiO2/NFs) have been synthesized through an electrospinning method and annealed at 400, 500 and 600 degrees C to optimize their systems. The effects of annealing temperature on the electrochemical properties for lithium ion batteries (LIBs) are assessed. The obtained LIB properties for TiO2 nanofiber anodes annealed at 400 degrees C (denoted as TiO2/NFs-400) are much better than those of TiO2/NFs-500 and TiO2/NFs-600. The TiO2/NFs-400 anodes show good LIB performance with capacities of 180 and 150 mAh/g tested at 200 and 600 mA/g after 100 cycles with almost no capacity loss and superb rate performance. The XRD results show that the pure anatase phase TiO2 can form at 400 degrees C for TiO2/NFs-400, while mixed phases of anatase and rutile are emerged at TiO2/NFs-500 and TiO2/NFs-600. Furthermore, the TiO2 nanoparticles are combined in nanofibers, and their corresponding crystal particle size for TiO2/NFs-400 was smaller than that of the other two samples. It is concluded that the superior electrochemical performance of the TiO2/NFs-400 anodes could be due to their pure crystal of anatase, small nanoparticles and non-ideal crystal lattices.