Critical role of zeolites as H2S scavengers in argyrodite Li6PS5Cl solid electrolytes for all-solid-state batteries

Abstract

All-solid-state batteries (ASSBs) with inorganic solid electrolytes (SEs) have received much attention as future energy storage systems owing to their high energy densities and excellent safety. Sulfide-based SEs are considered promising because they exhibit greater ionic conductivities and mechanical softness than oxide-based SEs. In particular, argyrodite-type Li₆PS₅Cl with a high ionic conductivity of 3.0 × 10⁻³ S cm⁻¹ offers new possibilities for realizing high-performance ASSBs. However, contact with moisture results in the evolution of H₂S from Li₆PS₅Cl, which has hindered the scalable fabrication and practical application of Li₆PS₅Cl. To avoid this issue, we propose incorporating a zeolite, which can act as a scavenger for both toxic H₂S gas and moisture, as a functional additive in Li₆PS₅Cl. We demonstrate that zeolite-embedded Li₆PS₅Cl exhibits greatly improved chemical stability and reduced H₂S evolution upon storage in humid air (RH 50%), leading to a noticeable improvement in the cycle performance of ASSBs. This approach could resolve the technical issues associated with sulfide-based SEs toward commercial-scale implementation.