Solid oxide fuel cells (SOFC) were enhanced at Forschungszentrum Jülich the last five years to yield higher performance and better long-term stability. This development includes all facets of material science: the materials themselves (e.g. Fe perovskite cathodes); the processing of applied layers in terms of their thickness, paste/suspension parameters, and sintering regime; the adaptation of microstructure (porosity, particle sizes); and the combination of different material interfaces in the cell and the stack. The newest generation of cells yield approx. 900 mW/cm² at an operating temperature as low as 700°C (H2/3%H2O, air, 0.7 V) in single cell tests. In a stack the performance is still approx. 700 mW/cm² at the same operating conditions, whereas the slight decrease is owed to losses in the cell-interconnect interface.
As there does not exist an unified cell design for all currently investigated applications, three different types of cells are used at Forschungszentrum Jülich: (1) for stationary applications, (2) a cell with high-performance cathode, (3) and a light-weight cell with better redox stability in mobile applications (e.g. auxiliary power units). The differences in these types are presented and specific material problems addressed, e.g. diffusion barrier layers against undesired phase reactions. Furthermore, state-of-the-art fabrication routes are shown that are capable of being scaled-up for industry production with their specific advantages and characteristics.