Determination of Chromium Concentration in Solid Oxide Fuel Cell Cathodes: (La,Sr)MnO3 and (La,Sr)FeO3

Chromium poisoning was investigated at the cathode/Gd0.2Ce0.8O1.9 electrolyte interfaces under cathodic polarization by using a preoxidized Cr metal. The concentration levels of Cr in the porous cathodes [La0.8Sr0.2MnO3 (LSM) and La0.8Sr0.2FeO3 (LSF)] was first determined by secondary ion mass spectrometry. Maxima of Cr concentration were observed at the LSM/electrolyte interfaces (about 1000 ppm). On the other hand, no maxima of Cr concentration were observed with homogeneous distribution of Cr (1000-1700 ppm). The amount of Cr deposited in the LSF cathode is estimated to be about 21% of the supplied Cr and is about 1.6 times higher in the LSM. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3193701] All rights reserved.