Evaluation of magnesium ion migration in inorganic oxides by the bond valence site energy method

We have applied the bond valence site energy (BVSE) method elaborated in our earlier work for alkali ion conductors to investigate the migration of Mg ions through six types of inorganic (magnesium-containing) oxides and the effect of nonequivalent Mg sites within the crystal structures. The calculated migration pathways and barrier heights are compared with the results determined by density functional theory. Not only do the favorable migration pathways obtained by both methods demonstrate consistency, the migration barrier heights are clearly correlated, with the BVSE method typically overestimating the migration barrier heights relative to the density functional theory calculations. Overall, the most suitable primary application of the BVSE method is as an approximate screening tool for the structures of materials and to estimate the migration energies and pathways of magnesium ions through inorganic oxides.