All-solid-state batteries offer the potential to improve fast charging properties, the energy density as well as safety. For solid polymer electrolytes the main drawbacks are the low ionic conductivity at RT and the limited electrochemical stability window. Therefore, concepts for hybrid solid electrolytes (HSE) based on an organic polymer matrix and inorganic filler material are investigated, as they potentially combine the high ionic conductivity of inorganic with the mechanical performance of polymer-based solid electrolytes. Furthermore, the transport structure and interfaces within the electrode can be influenced through the manufacturing process.

In this contribution, passive as well as active (oxide/thiophosphate) filler particles were functionalized with silane-based ligands to achieve a homogeneous distribution and enhance the interface contact. The effect of the filler type and content on the ionic conductivity was studied via electrochemical impedance spectroscopy. Thiophosphate filler particles were synthesized via a scalable mechanochemical process route. For the resulting HSE the influence of the process parameters for a solvent-based manufacturing process were studied and an ionic conductivity of 10^-4 S cm^-1 at RT was obtained for a filler content of 2.5 vol.-%. Besides, silane functionalized HSEs showed no H2S formation and therefore the safety was significantly improved compared to pure thiophosphates. For a solvent-based processed HSE with LATP filler particles an ionic conductivity of 3.5∙10^-5 S cm^-1 at RT was obtained for a filler content of 10 vol.-%. Additionally, for the HSE with oxide filler particles a scalable dry process route was developed in order to reduce manufacturing costs and the residual HSE porosity. The process chain consisting of a plastification and calendering step was investigated regarding process parameters like the kneading temperature and time. Here, an improved ionic conductivity of 1.2∙10^-4 S cm^-1 at RT was achieved.