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.

迄今针对运行时长超11年的固体氧化物燃料电池（SOFC, Solid Oxide Fuel Cell）样品开展的后测试表征结果显示，除其他观测现象外，钆掺杂二氧化铈（gadolinium-doped ceria）阻挡层与La₀.₅₈Sr₀.₄Co₀.₂Fe₀.₈O₃₋δ（简称LSCF）阴极的界面处生成了杂质。一方面，通过扫描电子显微镜（SEM, Scanning Electron Microscopy）与透射电子显微镜（TEM, Transmission Electron Microscopy）分析，已在该界面处检测到外来元素铬；另一方面，研究证实界面处的多数LSCF晶粒的元素组成存在差异。尽管可通过TEM完成界面杂质的元素组成分析，但目前仍未能揭示杂质的局部晶体结构及其变化。鉴于此，具备超高横向分辨率的X射线劳厄微衍射（X-ray Laue microdiffraction）或可成为厘清化学组成局部变化是否会引发材料结构改变的关键分析工具——例如LSCF是否会局部从钙钛矿结构转变为拉德尔斯登-波珀/双钙钛矿结构。