Lithium Coordination Sites in Li_<i>x</i>TiO₂(B): A Structural and Computational Study

Abstract

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 LixTiO2(B) in bulk and nanowire form. LixTiO2(B) is a promising anode material for rechargeable lithium batteries. Three structures were identified, Li0.25TiO2(B), Li0.5TiO2(B), and LixTiO2(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, (Li0.5TiO2(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.