The intercalation phase diagram of Mg in V2O5 from first-principles

G. Sai Gautam, P. Canepa, A. Abdellahi, A. Urban, R. Malik, and G. Ceder; Chem. Mater. 27, 3733-3742 (2015)


We have investigated Mg intercalation into orthorhombic V2O5, one of only three cathodes known to reversibly intercalate Mg ions. By calculating the ground-state MgxV2O5 configurations and by developing a cluster expansion for the configurational disorder in δ-V2O5, a full temperature–composition phase diagram is derived. Our calculations indicate an equilibrium phase-separating behavior between fully demagnesiated α-V2O5 and fully magnesiated δ-V2O5, but also motivate the existence of potentially metastable solid solution transformation paths in both phases. We find significantly better mobility for Mg in the δ polymorph, suggesting that better performance can be achieved by cycling Mg in the δ phase.

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