Crystal structure prediction of Li4x Mg2(1-x)P2O7 by first-principles calculations

We conduct first-principles calculations to investigate the phase stability of the pseudo-binary Li4x Mg2(1−x)P2O7 system, a promising solid electrolyte material. Our approach involves exploring stable structures through crystal structure prediction simulations and the generation of structures by cation substitution. We then discuss the phase stability of four P2O7 frameworks. For the composition of Li2MgP2O7, we find that the structure with the same P2O7 framework as Li2.2Zn0.8P2O7 exhibits the lowest formation energy. Our results agree well with the experimental results and provide insights into material design within the Li-Mg-P-O quaternary system for next-generation battery technology.