Chromium poisoning effects on performance of (La, Sr) MnO3-based cathode in anode-supported solid oxide fuel cells
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Citation (published version)Ruofan Wang, Uday Pal, Srikanth Gopalan, Soumendra Basu. 2017. "Chromium poisoning effects on performance of (La, Sr) MnO3-based cathode in anode-supported solid oxide fuel cells." Journal of The Electrochemical Society, Volume 164, Issue 7, pp. 740 - 747 (8).
Chromium (Cr) vapor species from chromia-forming alloy interconnects are known to cause cathode performance degradation in solid oxide fuel cells (SOFCs). To understand the impact of Cr-poisoning on cathode performance, it is important to determine its effects on different cathode polarization losses. In this study, anode-supported SOFCs, with a (La,Sr)MnO3 (LSM) + yttria-stabilized zirconia (YSZ) cathode active layer and a LSM cathode current collector layer were fabricated. At 800°C, cells were electrochemically tested in direct contact with Crofer22H meshes, under different cathode atmospheres (dry air or humidified air) and current conditions (open-circuit or galvanostatic). Significant performance degradation was observed when cell was tested under galvanostatic condition (0.5 A/cm2), which was not the case under open-circuit condition. Humidity was found to accelerate the performance degradation. By curve-fitting the experimentally measured current-voltage traces to a polarization model, the effects of Cr-poisoning on different cathodic polarization losses were estimated. It is found that, under normal operating conditions, increase of activation polarization dominates the cathode performance degradation. Microstructures of the cathodes were characterized and Cr-containing deposits were identified. Higher concentrations of Cr-containing deposits were found at the cathode/electrolyte interface and the amounts directly correlated with the cell performance degradations.
Rights© The Author(s) 2017. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. [DOI: 10.1149/2.0441707jes] All rights reserved.