Prediction of defect structure in lithiated tin- and titanium-doped α-Fe₂O₃ using atomistic simulation

The defect structure of lithiated tin- and titanium-doped α-Fe₂O₃ has been assessed using interatomic potential calculations. Of the models considered for lithiation, a model in which Li⁺ occupies an interstitial site balanced by the reduction of Fe³⁺ to Fe²⁺ on an Fe³⁺ site was found to be more favourable than the substitution of Li⁺ on an Fe³⁺ octahedral site balanced by an O^2- vacancy. Insertion of lithium into the interstitial site between two adjacent M⁴⁺ ions was particularly favourable. The calculated lattice parameters decrease on lithiation as has been observed experimentally.