Conductivity, elastic moduli and phase transitions in the Li10GeP2O12 solid-state electrolyte from first-principles molecular dynamics

Superionic materials are ideal candidates to replace the conductive but flammable liquid organic electrolytes currently used, leading to prospectively safer all-solid-state batteries. Aiming to find highly conductive candidates that have the appealing electrochemical properties of an oxide, we study here extensively LGPO, the oxide analogue of LGPS, one of the best conducting solid-state electrolytes. We find that for LGPO a hypothetical tetragonal phase mirroring that of LGPS would be highly conductive. We thus employ isobaric-isoenthalpic simulations to explore phase stability and phase transitions, while extracting from the trajectories the relevant elastic moduli.