Amorphous solid electrolytes containing large amount of Li2S were prepared in the system Li2S–GeS2–P2S5 by a high-energy ball-milling process. The region of amorphous-sample formation by the ball-milling process was much wider than the glass-forming region by a conventional melt-quenching method. The addition of a second network-forming sulfide, GeS2, to the Li2S–P2S5 system caused an enhancement of ion conductivities of the amorphous samples. The 95Li3PS4·5Li4GeS4 amorphous sample exhibited the highest lithium-ion conductivity 4.0 x 10−4S/cm at room temperature among the obtained amorphous samples in the system Li2S–GeS2–P2S5. DC polarization measurements suggested that lithium-ion transport number of the 95Li3PS4·5Li4GeS4 sample was almost unity.

A Mixed-Former Effect on Lithium-Ion Conductivities of the Li2S–GeS2–P2S5 Amorphous Materials Prepared by a High-Energy Ball-Milling Process. H.Yamamoto, N.Machida, T.Shigematsu: Solid State Ionics, 2004, 175[1-4], 707-11