Atmospheric Influences on Li6PS5Cl Separators and the Resulting Ionic Conductivity for All-Solid-State Batteries

All-solid-state batteries (ASSBs), defined through a solid electrolyte, are emerging as a promising solution to address current challenges in energy and power density demands for electromobility. Within the various possible types of solid electrolytes, sulfide-based materials exhibit advantageous high ionic conductivities. However, due to the strong reactivity of sulfides, atmospheric exposure can lead to the formation of toxic hydrogen sulfide and additionally negatively impact the resulting battery performance. Both factors present key challenges for ASSB production, as they necessitate the development of a material-adapted, economically viable and safe process atmosphere. In the present study, the influence of different production atmospheres on sulfide-based solid electrolytes is experimentally investigated. For this purpose, sulfide sheets are exposed to defined atmospheres with dynamic air fluctuations at dew points ranging from −60 °C to 0 °C. The resulting ionic conductivities indicate a dependency on the prevailing dew point and exposure time with a discernible impact on performance even at dew points of −60 °C within atmospheres with constant air circulation. With the acquired results, a detailed and knowledge-based selection and design of dry room production atmospheres for ASSB cell assembly is possible, which is a necessary step for further industrialization.