Facile hydrothermal synthesis of single crystalline TiOF_2 nanocubes and their phase transitions to TiO_2 hollow nanocages as anode materials for lithium-ion battery

摘要

Single-crystalline TiOF_2 nanocubes with edge length of around 200-300 nm have been synthesized under hydrothermal conditions using titanium (IV) isopropoxide (TIP) as titanium source, HF as etchant. The corresponding hollow TiO_2 nanocages with dominantly exposed {001} crystal planes can be easily obtained by calcinating TiOF_2 nanocubes under air atmosphere. It is also found that the presence of acetic acid not only being chemical modifier of TIP to lower its reactivity at relatively acid environment, but also gives rise to a uniform hollow TiO_2 nanocages which play the crucial role in hollow formation. The TiOF_2 electrode presented here exhibits much excellent electrochemical performance. The initial high specific capacity of TiOF_2 can be up to 1045 mAh g~(-1) at a rate of 30 mA g~(-1). The specific discharge capacity is 510 mAh g~(-1) after 40 cycles.