Long-term measurements of anode-supported solid oxide fuel cells with lscf cathodes under various operating conditions

Abstract

Anode-supported SOFCs with La0.58Sr0.4Co 0.2Fe0.8O3-δ (LSCF) cathodes, Ce 0.8Gd0.2O2.δ interlayers and yttria-stabilised zirconia electrolytes show a significantly higher power output than cells with (La,Sr)MnO3.δ-based cathodes in single cell tests. However, these cells show a rather high degradation rate of 1.0 - 1.5% per 1000 h. Therefore, the long-term stability of seven LSCF-based cells was evaluated over 1000 hours of operation under varied constant operating conditions to evaluate the parameters forcing the cell degradation. The tests were carried out at temperatures of 800°C and 700°C as well as at current densities of 0.3 and 0.6 A/cm2. Furthermore, the influence of a higher reduction temperature of the anode was evaluated. The results show that it is vitally important to compare the degradation rates at identical operating points for evaluation of the parameters influencing the degradation. While a lower temperature resulted in a significantly reduced degradation, the current density and reduction temperature did not have a clear impact on the degradation.