Low-Temperature Chromium Poisoning of SOFC Cathode

Abstract

Low-Temperature Solid Oxide Fuel Cells (LT-SOFCs), operating in 500-700 °C temperature range on fossil derived hydrocarbon fuels, are widely viewed as the “next generation” of clean and efficient electrochemical power generation technology that may also remain prone to gaseous chromium assisted cathode poisoning. Chromium poisoning of strontium doped lanthanum manganite (LSM) and lanthanum strontium cobalt ferrite (LSCF) cathodes have been studied in half-cell configuration at 650 °C in gaseous chromium vapor containing humidified air. The electrochemical performance of LSM/YSZ/Pt half-cell shows faster degradation in chromium containing air with a rapid change in the polarization resistance compared to LSCF/GDC/Pt half-cell. Electrode chemistry, morphology and elemental distribution have been studied using Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDX) and X-ray Diffraction (XRD) techniques. A thermodynamic analysis of the degradation process was also conducted. Our observations show that lowering of cell operating temperature may not significantly lower the cell performance degradation. Possible approaches for mitigating above degradation will be discussed.