Synthesis and electrochemical performance of high-rate dual-phase Li_4Ti_5O_(12)-TiO_2 nanocrystallines for Li-ion batteries

摘要

Dual-phase Li_4Ti_5O_(12)-TiO_2 nanocrystallines are prepared by a hydrothermal process and subsequent heat treatment. The as-prepared Li_4Ti_5O_(12)-TiO_2 nanocrystallines measure around 15-25 nm in size and have abundant phase interfaces. Electrochemical measurements demonstrate that dual-phase Li_4Ti_5O_(12)-TiO_2 exhibit good electrochemical performance over individual single-phase Li_4Ti_5O_(12), especially at high current rates. Initial discharge capacities of dual-phase Li_4Ti_5O_(12)-TiO_2 nanocrystallines are 241 and 202 mAh g~(-1) at discharge rates of 0.2 and 5 C, respectively. Even after 50 cycles at 20 C, the capacity still remains 140 mAh g~(-1), which is four times greater than that of single-phase Li_4Ti_5O_(12) (29 mAh g~(-1)). The high electrochemical performance indicates that dual-phase Li_4Ti_5O_(12)-TiO_2 nanocrystallines are highly promising anode materials for lithium ion battery applications.