Diffuson-related transport in ionically conducting solids

In DIONISOS, we aim to develop new analytical relationships for ion- and heat-transport in ionicconductors, and thus heal significant inconsistencies of the current understanding. Currently ion- andheat transport are interpreted as unrelated phenomena; ion transport being based on local jumps,whereas heat transport being mediated by dynamic lattice vibrations called phonons.Among other studies, my pioneering works in the field of solid ionic conductors (J. Am. Chem. Soc.2017, J. Am. Chem. Soc. 2018) opened discussions about plausibility-gaps in state-of-the-artconcepts, in particular regarding interactions of phonons with mobile ions. Our work has shown thatby tailoring the lattice dynamics and vibrational properties of materials, the ionic transport can beaffected, which cannot be explained well by current models.To this end, we propose to analyze both ion- and heat-transport in several representative materials,designed for the purpose, to test our hypothesis that it is not a classical phonon phenomenon, butrather local vibrations, quantized by the diffuson, that dominate the heat and ionic transport in fastionic conductors.DIONISOS will thus provide an in-depth fundamental understanding of how local vibrational modesconnect thermal to ionic transport, and ideally a new analytical relationship. A unified understandingof thermal transport and ionic transport will pave the way for further research on how local structuralphenomena affect global materials properties. In addition, a theory of linking local ionic motion withlocal thermal motion will be of vast value for the design of high-performance functional materials.