A mixed-former effect on lithium-ion conductivities of the Li2S-GeS2-P2S5 amorphous materials prepared by a high-energy ball-milling process
Abstract Amorphous solid electrolytes containing large amount of Li 2 S were prepared in the system Li 2 S–GeS 2 –P 2 S 5 by a high-energy ball-milling process. The region of amorphous-sample formation by the ball-milling process is much wider than the glass-forming region by a conventional melt-quenching method. The addition of a second network-forming sulfide, GeS 2 , to the Li 2 S–P 2 S 5 system caused an enhancement of ion conductivities of the amorphous samples. The 95Li 3 PS 4 ·5Li 4 GeS 4 amorphous sample showed the highest lithium-ion conductivity 4.0×10 −4 S cm −1 at room temperature among the obtained amorphous samples in the system Li 2 S–GeS 2 –P 2 S 5 . DC polarization measurements suggested that lithium-ion transport number of the 95Li 3 PS 4 ·5Li 4 GeS 4 sample was almost unity.