Microstructural evolution of solution-processed Li–Ge–Ga–S chalcogenide powders for Li+ ion battery applications

• Chalcogenide electrolyte in the Li–Ge–Ga–S system is prepared via a solution-based process.
• The conductivity is comparable with that of analogues prepared via MQ or MA technique.
• The conductivity turns out to depend mainly on amorphization of the prepared powders.

Sulfur-based chalcogenide Li–Ge–Ga–S powders for use in solid electrolyte of Li+ ion batteries have been successfully synthesized via a low-temperature solution-based process. Their Li+ ion conductivity turns out to be ~ 7 × 10− 4 S/cm at room temperature which is quite comparable with that of melt-quenched or mechanically-alloyed analogues. It is revealed that their microstructure becomes amorphized appropriately at a specific Ga/Ge ratio where the ionic conductivity is maximized. A structural model is proposed, which emphasizes correlations between gallium and lithium inside the amorphous structures.