The principal objective of this study is to develop in situ imaging techniques that allow the direct observation of solid oxide fuel cell (SOFC) anodes under operational conditions and provide a scientific and engineering understanding of degradation in SOFC anodes. Meeting this objective will help enhance SOFC long term performance and reliability and enable SOFCs as a viable technology for efficient and sustainable energy conversion. High resolution in situ x-ray imaging using a newly developed transmission x-ray microscope (TXM) will be used to achieve this goal. The PI will use hard x-ray nanotomography developed by him at the Argonne National Laboratory Advanced Photon Source (APS) to nondestructively obtain high resolution (32 nm) 3-D images of an operating SOFC anode. The PI will develop in situ x-ray imaging and spectroscopy techniques to observe anode degradation during operation and perform detailed microstructural analysis to understand degradation mechanisms in SOFC anodes. Aged SOFC anodes will be provided by the Ecole Polytechnique Federale de Lausanne (EPFL). Preliminary results obtained from ex situ nondestructive 3-D imaging of SOFC anodes indicate Ni-phase particle coarsening is significantly affected by operational time. This project will build on the preliminary results to elucidate fundamental knowledge regarding the mechanisms and pathways that cause degradation. This project will involve two graduate students and will have outreach activities for undergraduate and high school students. Intellectual merit includes a detailed understanding of SOFC anode degradation due to Ni coarsening during operation and its effect on performance. Knowledge obtained from this study will be used to elucidate degradation mechanisms, especially the role of different coarsening mechanisms (Ostwald ripening, particle migration, and evaporation), the corresponding operating conditions in which they occur, and how and where such mechanisms originate in the microstructure. The research team assembled for this study works extensively in the area of SOFCs including x-ray imaging of SOFC materials, detailed charge-transfer modeling and testing, thermal stress, and material characterization. Broader impacts of this study include external collaborations that will explore new sustainable energy technologies for our society. EPFL will provide SOFC samples, perform experiments, and provide data for model validation. APS will provide synchrotron facilities to image SOFC electrode samples using a 32 nm resolution hard x-ray microscope system. In terms of education, the PI will work closely with the UConn Engineering Diversity Program to identify several top high school students, especially from underrepresented groups, from over 25 local area high schools for a summer internship in the PI's lab. The PI and his students will engage in on-site research at EPFL and APS.
