Chromium Deposition and Poisoning at Ba0.5Sr0.5Co0.8Fe0.2O3-delta Cathode of Solid Oxide Fuel Cells

Chromium deposition and poisoning at Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) cathodes of solid oxide fuel cells are investigated. BSCF cathode shows an excellent and stable performance in the absence of metallic interconnects. However, in the presence of a chromia-forming metallic interconnect performance of the BSCF cathodes degrades quickly. Chromium deposition was observed on the BSCF cathode surface after 1200 min polarization at 900 and 800 degrees C. The Cr2O3/SrO and Cr2O3/BaCO3 oxide couple study indicates that SrCrO4, BaCrO4, and BaCr2O4 start to form at temperatures above 500 degrees C. The results indicate that BSCF cathode is not chromium-tolerant despite its superior activity for the O-2 reduction reaction. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3549169] All rights reserved.