The mixed glass former effect represents a key problem for our general understanding of ion transport in glasses and manifests itself in a strong rise of the ionic conductivity upon mixing of two network formers, as, for example, silicate and borate. It is of crucial importance for optimizing ionic conductivities in glassy materials and is exploited in various electrochemical devices such as batteries, chemical sensors, smart windows or super-capacitors. This project aims at a fundamental theoretical understanding of the mixed glass former effect based on a multi-scale approach. Starting from electronic structure calculations of atomic cluster configurations, parameters for potential models of representative mixed glass former systems are calculated and subsequently used in molecular dynamics simulations of the materials. These simulations are then applied to determine ionic sites and diffusion pathways and their energetic characteristics, which finally are used for the development of suitable coarse-grained models for the hopping dynamics of the mobile ions. The close collaboration with leading experts in the US and Europe will allow us to validate the modeling by detailed comparison with results from X-ray and neutron scattering and corresponding Reverse Monte Carlo structures, from Raman and infrared spectroscopy, from NMR studies, from impedance spectroscopy, and from tracer diffusion measurements.

The project is part of a joint DFG/NSF project "An International Collaborative Educational and Research Program in the Study of the Mixed Glass Former Phenomena in Materials" in the Materials World-Network. The project team consist of 3 partners from the USA and 3 partners from Europe.