Sodium-Ion Conducting Solid Electrolytes in the Na₂S–In₂S₃ System

抄録

The development of solid electrolytes is necessary for practical applications of all-solid-state Na-ion batteries. In this study, we systematically developed sulfide Na-ion conductors with central In cations, prepared by solid-state reaction and mechanochemical methods. Thermodynamically stable crystals of Na₅InS₄ and NaInS₂ were obtained by the solid-state reaction method, whereas amorphous and/or metastable phases were produced by the mechanochemical method. Two new metastable phases, Na₅InS₄ and NaInS₂, are expected to be examined in the future as end-members of sulfide Na-ion conductors with central In cations.