A Mechano-Chemical Synthesis of Lithium-Ion Conductive Amorphous Materials in the System Li₂S-GeS₂

Abstract

Lithium-ion-conducting amorphous materials in the system Li₂S-GeS₂ were prepared by use of a high-energy ball-milling process. The amorphous materials were obtained over the wide composition range up to 66.7mol%Li₂S content. The composition range in which the amorphous materials were obtained by the ball-milling process was much wider than the glass-forming region by conventional melt-quenching methods. The lithium-ion conductivities of the obtained amorphous materials increased with an increase in the Li₂S content. The activation energies for conduction correspondingly decreased with increasing the Li₂S content. The 66.7Li₂S⋅33.3GeS₂(mol%) sample showed the maximum conductivity 1.1×10^-4Scm^-1 at 298 K.DC polarization measurements suggested that a lithiumion transport number was almost unity for the obtained amorphous materials.