二氧化钛纳米管中锂离子嵌入和扩散的第一性原理研究

iO2 nanotube is a highly promising anode material for rechargeable Li-ion batteries. Computational studies based on density functional theory (DFT) have been performed for TiO2 nanotubes aiming at key issues related to lithium insertion sites and lithium diffusion properties. As a possible vacancy, oxygen vacancy cannot be fully eliminated with current fabrication procedures in TiO2 nanotubes and it can affect the electronic structures and properties of TiO2 nanotubes. Our electronic structure calculations show lithium is favorable on both inner and outer surface of perfect and oxygen-vacancy doped TiO2 nanotubes at low lithium concentration. A systematic investigation of the effect of oxygen vacancy on Li-ion diffusion suggests that the bridging oxygen plays a very positive role in the Li-ion diffusion, the barrier energies of the stable diffusion pathway decrease from 0.8 eV to 0.55 eV. One-dimensional anatase nanotubes have an advantage in lithium ion diffusion compared with bulk anatase (0.623 eV) and other nanotube materials (>1.8 eV).