Theoretical study of Li intercalation in TiO2(B) surfaces

Abstract

TiO2(B) has potential as an anode material for Li-ion batteries. Although theoretical and experimental studies related to the intercalation of Lithium (Li) in TiO2(B) already exist, to the best of our knowledge there are no studies in the open literature related to Li intercalation in low-index surfaces of this oxide phase. Therefore, we study the intercalation of Li in the (100) and (001) surfaces of TiO2(B) using Density Functional Theory (DFT). The DFT + U Hubbard methodology was included to consider the strong correlation of the “d” electron states of the transition metal. Electronic densities of states of the surfaces were analyzed in the diluted limit concentration of Li. We found a small-induced magnetic moment present. The diffusion of Li atoms in the surfaces was studied using the Nudged Elastic Band (NEB) method. Our results indicated that the Li intercalation in the (100) and the (001) surfaces is a favorable process. Moreover, we found diffusion pathways energetically stables for both surfaces. Calculations of charge density difference with Li intercalated in the energetically stable positions on the surfaces indicate that the charge density on Li is a local phenomenon and a charge transfer occurs from Li to the nearest Ti and O atoms.