The mechanism of H_2S poisoning Ni/YSZ electrode studied by impedance spectroscopy

摘要

The two specific processes of hydrogen sulfide poisoning a solid oxide fuel cell (SOFC) were studied by impedance spectroscopy in galvanostatic mode at 800°C. The polarization resistance increased by exposure to H_2 S within 30 min and then remained nearly stable in the subsequent aging test, accounting for an abrupt cell performance drop. A successive sluggish degradation was corresponding to the slow increase of the series resistance, which can be attributed to the contaminated nickel catalyst at the yttria-stabilized zirconia (Ni/YSZ) anode supported layer. The results indicated the establishment of a two-step mechanism of H_2 S poisoning an SOFC.