Sudden Deterioration in Performance During Discharge of Anode-supported Solid Oxide Fuel Cells

Abstract

The stability of the anode-supported solid oxide fuel cell consisting of Ni-YSZ|YSZ|LSM was examined at 800°C by monitoring the current density at a constant terminal voltage of 0.5 V. Although stable power generation was possible within initial 60 min, gradual decrease and subsequent sudden drop in current density were observed: a series of this behavior was different from that observed in limiting current density. This behavior is suggested to be one of the degradation factors related with transport of gas species in the pores of the electrode. In response to performance deterioration, a drastic increase in ohmic loss and impedance was confirmed soon after the discharge operation. It is noted, however, that the deteriorated performance was reversibly recovered depending on the holding time under the open-circuit condition. Analogous phenomena occurred with the cell consisted of Ni-YSZ|YSZ|Ce_0.8Sm_0.2O_1.9|La_0.6Sr_0.4Co_0.2Fe_0.8O₃, indicating that the cause of the sudden deterioration was in the anode side.