Three-dimensional reconstruction and analysis of an entire solid oxide fuel cell by full-field transmission X-ray microscopy

An entire active region of an anode-supported solid oxide fuel cell was structurally analyzed by X-ray computed nano-tomography using full-field transmission X-ray microscopy (NANO-TXM). A total three-dimensional volume of ∼38,500 μm3 was imaged, from which Ni–YSZ anode functional layer (∼3650 μm3) and LSM–YSZ cathode functional layer (∼4100 μm3) volumes were reconstructed. These were among the largest-volume electrode reconstructions ever reported, while at the same time exhibiting high spatial resolution of 50 nm. Comparison with electrode microstructures measured using other imaging methods demonstrates that the larger NANO-TXM-measured volumes provided significantly more accurate phase connectivity information. A microstructure-based electrochemical model prediction agreed well with the measured full-cell electrochemical data. The results suggest that low LSM connectivity and slow oxygen reduction reaction kinetics in the cathode were a major limitation to the overall cell performance.

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► Reconstruction of entire SOFC active region in a single set of NANO-TXM measurements.
► Cathode had 3.3× increase in TPB density due to smaller particles sizes.
► Modeled performance suggests cathode made up 85% of electrode polarization.
► LSM connectivity and sluggish TPB reaction kinetics limit cathode performance.