No abstract

TiO 2 -B is a highly promising anode material for rechargeable lithium batteries. Computational studies based on density functional theory (DFT) have been carried out on this material focusing on key issues relating to lithium insertion sites and lithium diffusion paths. Our simulation model shows good reproduction of the observed crystal structure of TiO 2 -B. Electronic structure calculations suggest that the lowest energy lithium site is a slightly off-center position in the b-axis channel for low lithium concentration (x < 0.125 for Li x TiO 2 -B). Our calculated cell voltages are compatible with values from electrochemical measurements. Low Li migration energies are found for pathways along the b-axis channel and the [001] c-axis direction, suggesting significant Li ion mobility in this anode material.

A combination of powder neutron diffraction and computational methods, based on density functional theory (DFT), have been applied to study the evolution of structure with Li content for Li x TiO 2 (B) in bulk and nanowire form. Li x TiO 2 (B) is a promising anode material for rechargeable lithium batteries. Three structures were identified, Li 0.25 TiO 2 (B), Li 0.5 TiO 2 (B), and Li x TiO 2 (B), where x corresponds to the maximum Li content, 0.8 (bulk) and 0.9 (nanowires). Together the techniques demonstrate that at low lithium concentration (up to 0.25) the square planar lithium site at the center of the b axis channel (C site) is preferentially occupied. At higher concentration, (Li 0.5 TiO 2 (B)) the C site becomes unfavorable and the 5-coordinate A1 site is occupied, whereas at the highest Li content, both A1 and a further 5-coordinate site, A2, are occupied equally.