The development of safe and high-performance all-solid-state batteries (ASSB) is contingent on creating fast ion conductors that combine high ionic conductivity with good ductility and chemical stability in a large voltage window, while – especially - mastering the interface of the solid electrolyte with the electrode materials. This presentation will examine ways to address these factors with new materials, while also shedding light on design concepts for ion conductivity.

The talk will cover an overview of the state-of-the art in the field, followed by a focus on recent findings in our laboratory concerning a) synthesis of thiophosphate-halide argyrodites, where very significant increases in conductivity above that of the parent Li₆PS₅Cl phase have been attained by both tuning composition and developing “clean” solution-engineering processing routes to these materials; b) creation of novel thiophosphate-halide and related structures that exhibit both ion conductivities above 1 mS/cm and good chemical stability; c) understanding the critical role that the anion framework plays in dictating ion conductivity using a combination of room/high temperature X-ray/neutron diffraction, NMR, and ab initio molecular dynamics simulations; d) examination of the interface of the solid state electrolytes at the positive and negative electrodes in practical ASSBs.