3D Imaging of Fuel Cell Cathodes Scott Barnett & Peter Voorhees (Northwestern) DMR Katsuyo Thornton (Univ Michigan) DMR Stuart Adler (Univ Washington) DMR This project aims at three- dimensional imaging of solid oxide fuel cells (SOFCs), an important technology for clean efficient electrical generation. A key part of the SOFC is the cathode, typically a mixture of two oxides - (La,Sr)MnO 3 (LSM) and Y 2 O 3 -stabilized ZrO 2 (YSZ). Quantitative cathode data has not been available due to a lack of three-dimensional imaging methods and poor resolvability of the oxides. The figure at right shows a representative three-dimensional image: green is LSM, blue represents pores, and translucent is YSZ. Images such as this provide key input for connecting cathode processing with microstructure and the resulting cathode performance. The results are important for improving performance and predicting long-term stability.

The preparation and initial characterization of the cathode samples in this study were done by Sherri Rukes, a RET high school teacher. She will be a co-author on two publications arising from this work. The cathodes were prepared from standard materials using common methods and yielded performance comparable to many reported in the literature, so the results should be useful to the broader SOFC community. In collaboration with Prof. Daniel Mumm at University of California-Irvine (a current NSF CAREER awardee), microscopy methods were developed for resolving different oxides in cathodes and for epoxy infiltration, allowing quick and definitive image interpretation. The image at left shows an example of the high- quality images obtained. In collaboration with a math group at Rutgers, we have developed methods for analyzing the connectivity of phases in electrodes. 3D Imaging of Fuel Cell Cathodes Scott Barnett & Peter Voorhees (Northwestern) DMR Katsuyo Thornton (Univ Michigan) DMR Stuart Adler (Univ Washington) DMR LSM- YSZ - Pore

3D Imaging of Fuel Cell Cathodes Scott Barnett & Peter Voorhees (Northwestern) DMR Katsuyo Thornton (Univ Michigan) DMR Stuart Adler (Univ Washington) DMR The image at left shows a “fly through” of the entire set of images making up the three- dimensional data set of a LSM- YSZ cathode.