Deterioration process of argyrodite solid electrolytes during exposure to humidity-controlled air

Sulfide-based solid electrolytes (SEs) are among the most promising candidates for realizing all-solid-state lithium-ion batteries due to their high ionic conductivity. However, low atmospheric stability is a major drawback. When exposed air, conductivity precipitously decreases, along with toxic H2S gas generation, mainly from reaction between SEs and water molecules in air. Understanding sulfide-based deterioration mechanism under air exposure necessary develop them stability. This study investigated degradation process of primarily by transmission electron microscope (TEM) observation. As SE batteries, we focused on argyrodite exhibiting Besides H2O CO2 TEM observations revealed that decomposed decreased crystallinity, followed components generation. The main factor discussed based products caused exposure.