Characterisation of sulphur poisoning of anodes in single-cell SOFC stacks using impedance spectroscopy

The effect of H2S on single cell stack power using simulated syngas and hydrogen/steam mixture as a fuel is investigated using impedance spectroscopy. The different concentrations of H2S (2-50 ppm) were added to the pre-mixed reformate containing H2, CO, CO2, H2O, CH4 and N2 during cell operation. Electrolyte supported cells are tested at operation temperature of 850°C. The effect of different concentrations of H2S and steam on sulphur tolerance of cells is investigated. The impedance measurements are carried out to identify the processes which take place in the anode. The reversibility of sulphur poisoning is investigated and the observed regeneration processes are discussed. X-ray diffractometer (XRD) was used to characterize the microstructural changes that occurred after H2S poisoning.