Phase Transformation and Diffusion Kinetics of V2O5 Electrode in Rechargeable Li and Mg Batteries: A First-Principle Study

Using the density functional theory (DFT), first-principles computations were performed to investigate the intercalation site, phase transformation, electronic properties, and migration energy barrier of Li and Mg atoms in V2O5 to thoroughly illuminate the phase transformation and microscopic interaction as well as the migration mechanism of Li and Mg in V2O5. It is found that Li and Mg atoms prefer to locate at the site that is above, near the center of the quadrilateral composed of four V atoms. With the increase of the intercalation concentration (0 ≤ x ≤ 1), V2O5 undergoes a structural transformation from α-phase to ε-phase and δ-phase. Compared with ε-M0.5V2O5 (M = Li/Mg), the electronic conductivity of δ-MV2O5 (M = Li/Mg) is declined. On the basis of diffusion kinetics, Mg exhibits more difficulty in inserting and extracting in V2O5 than Li. This study can be useful for the further application of V2O5 in Mg ion batteries.