This proposal takes as its starting point the development of new patented proton conducting oxides, synthesis routes, and fabrication of fuel cell prototypes under the NANOMAT FOET project. Nano-science and modelling tools will be applied where particular challenges have been identified, namely on interfaces: surfaces, and electrodes. The project addresses structures, defects, charge distributions, transport, and kinetics on these interfaces. The goal is to help design materials and combinations of materi als with composition, processing, and resulting microstructure such that resistance to high charge transfer through these interfaces is minimised. The modelling work will be based on density functional theory (DFT), and will be devoted to calculations of electrodes (ion-electron conductor interface) and surfaces (of ion or electron conductor), of their structure, of the energies and dynamics of defects, and of heterogeneous reaction rates. Moreover, real interfaces will be studied on the atomic level with high resolution electron microscopy (HREM) and surface probe microscopy (SPM). Chemical characterisation will be performed with electron energy loss spectroscopy (EELS), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) a nd secondary ion mass spectroscopy (SIMS), aided by high-temperature environmental scanning electron microscopy (ESEM). The project is led by Dept. of Physics, University of Oslo (UiO), with supporting activities from Dept. of Chemistry, UiO, and SINTEF. The project will run paralell and interact with the nanoPCFC project funded under the same NANOMAT call. Materials synthesis and fabrication will be performed by collaborators at NTNU. The project educates 2 PhD candidates and involves additionally 2 res earcher recruiting positions.