The Effect of Manganese and Cobalt Doping on Chromium Deposition at Pt/YSZ Cathode Interfaces

Abstract

The performance of solid oxide fuel cells (SOFCs) can be degraded by chromium deposition, the amount and location of which can be affected by the compositions of the electrolyte and electrodes. Understanding compositional effects, especially at SOFC operating conditions, is important for the selection of materials that will minimize the impact of chromium deposition. In this study, the effect of YSZ doping on Cr deposition at a Pt-electrode/YSZ-electrolyte interface was investigated. Comparison between undoped and doped YSZ electrolyte surfaces after cathodic polarization for 25 hours in moist air at 800 ºC in the presence of chromia indicated that the presence of Mn or Co in the electrolyte significantly promotes Cr deposition at the electrode/electrolyte interface. The SEM micrographs of the Co-doped YSZ electrolyte surface after cathodic polarization for 10 to 45 hours clearly showed that with Co doping, deposition of Cr preferentially occurs at YSZ grain boundary.