Effect of operational conditions on long-term stability of SOFCs

Abstract

The long-term stability of anode supported solid oxide fuel cells (SOFCs) was investigated as a function of operating temperature and current density. The largest degradation rate was observed at the lower operating temperature and higher current density of 750°C and 0.75 A/cm2, respectively. Detailed characterization by impedance spectroscopy and post-test microscopy revealed that cathode degradation is the dominant contribution to the degradation under these conditions. A slight delamination at the cathode/electrolyte interface was observed. At higher operating temperatures, the degradation is generally less severe, even under higher current densities. Degradation rates as low as 2%/1000 h were observed at 850 and 950°C and 1.6 and 1.9 A/cm2, respectively, over operating periods of 1500 hours.