The research activities concentrate on the Physical Chemistry of ionically conducting materials (research field ‘Solid State Ionics’) in cooperation with national and international partners. The focus is on the transport properties and defect chemistry of mixed ionic-electronic conducting materials, including surface exchange reactions and transport through grain boundaries, but also pure ionic conductors are studied. The experimental investigations are supplemented by defect chemical modelling. With respect to application, the studies deal with novel materials for electrochemical energy conversion and storage, e.g. solid oxide and protonic fuel and electrolysis cells.