Film processing of Li6PS5Cl electrolyte using different binders and their combinations

The development of solid electrolytes has made significant progress in the last decade. Among the most promising materials, sulfide-based electrolytes show high ionic conductivities and low densities, and their precursors are abundant. For industrially relevant battery cells, sulfide electrolytes need to be processed to form thin electrolyte sheets that are either directly applied to the electrodes as coatings or prepared as stand-alone films. Thus, processing of sulfide electrolyte powders has recently drawn much attention as it seems to be one of the major challenges in realizing sulfide-based all-solid-state batteries. In this work, six different binders (NBR, HNBR, PIB, PBMA, SBS, SEBS) were selected for preparation of electrolyte films using Li6PS5Cl as a sulfidic model compound. The influence of the binders on the electrochemical performance as well as on the mechanical properties of the resulting films was investigated. In addition, binder blends were explored as a vial approach to optimize the properties of the electrolyte films. Special focus was put on elucidating the relation between the physico-chemical properties of the binder materials and the resulting electrochemical and mechanical properties of the electrolyte films.