Hirayama Masaaki

Crystal Structure of High-Temperature Phase of Lithium Ionic Conductor, Li3PS4

Crystal structure of the high-temperature phase of lithium ionic conductor, Li 3 PS 4 , was determined using high-temperature synchrotron X-ray diffraction data. Li 3 PS 4 belongs to the thio-LISICON (LIthium Super Ionic CONductor) family and shows high ionic conductivity above 500 K. The high-temperature α phase with space group, P b c n (60), has an orthorhombic cell parameter, a = 8.6125(2) A, b = 9.0211(2) A, and c = 8.42621(2) A at 906 K. The PS 4 tetrahedra are isolated with each other and form an alternating T + row and T - row, where T + and T - indicate that the apex of the tetrahedra is up and down, respectively. These PS 4 arrangements are different from those of the medium temperature β-phase and the low-temperature γ-phase.