Identifying (micro)structural degradation effects in solid oxide fuel cells operated for more than 11 years

The hitherto conducted post-test characterization of the SOFC samples operated for over 11 years revealed, inter alia, the formation of impurities at the interface between the gadolinium-doped ceria barrier layer and the La0.58Sr0.4Co0.2Fe0.8O3-d cathode. On the one hand, Cr as foreign element at the interface was detected by the SEM and TEM analysis. On the other hand, it was possible to show that many LSCF grains at the interface show differences in their elemental composition. While it was possible to analyze the elemental composition of the impurities at the interface via TEM, so far the local crystal structure of the impurities / changes could not be revealed. Therefore the extraordinary lateral resolution of the X-ray Laue microdiffraction could be the key analytical tool to clarify, if the local change in chemical composition also leads to a structural change of the material, e.g. LSCF locally transforms from a perovskite to a Ruddlesden-Popper / double perovskite structure.