Fast Mg2+ diffusion in Mo3(PO4) 3O for Mg batteries

In this work, we identify a new potential Mg battery cathode structure Mo-3(PO4) O-3, which is predicted to exhibit ultra-fast Mg2+ diffusion and relatively high voltage based on first-principles density functional theory calculations. Nudged elastic band calculations reveal that the migration barrier of the percolation channel is only similar to 80 meV, which is remarkably low, and comparable to the best Li-ion conductors. This low barrier is verified by ab initio molecular dynamics and kinetic Monte Carlo simulations. The voltage and specific energy are predicted to be similar to 1.98 V and similar to 173 W h kg(-1), respectively. If confirmed by experiments, this material would have the highest known Mg mobility among inorganic compounds.