Lithium superionic conductors Li10MP2O12 (M = Ge, Si)

The exploration for superionic conductors with new structures and compositions is challengeable for developing safer and high-energy-density batteries. Here, we report lithium superionic conductors with the compositions of Li[Formula: see text]GeP 2 O[Formula: see text] and Li[Formula: see text]SiP 2 O[Formula: see text]. The materials are prepared by melt-quenching and characterized by X-ray diffraction (XRD), AC impedance, DC polarization and cyclic voltammetry. Both germanium and silicon members demonstrate same orders of magnitude of bulk and grain-boundary conductivities of 10[Formula: see text] S[Formula: see text]cm[Formula: see text] at room temperature. The crystal structure is investigated by the Rietveld refinement of powder XRD and the migration mechanism of lithium ions is proposed.