The Correlation of Sulfur Distribution in LSCF and Performance Degradation under Different Operation Temperature

摘要

The sulfur poisoning behavior for the La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_3 (LSCF6428) cathode was examined at different operation temperatures of 923 K, 973 K, and 1073 K under a low concentration of SO_2 (0.01 ppm) condition, which is near the real environmental condition. The LSCF6428 cathode was prepared on the GDC electrolyte by screen-printing, and the degradation tests were carried out under galvanostatic condition for 300 h by feeding of 0.01 ppm SO_2-containing air with the flow rate of 50 ml/min. At 1073 K, the cathode performance did not change under cell test. The precipitates of SrSO_4 were observed in the vicinity of the gas inlet part, but that was not observed near the TPB of gas/LSCF/GDC, where electrochemical reactions occur. At 973 K and 923K, resistance for cathode reaction increased with increasing of operating time, and sulfur component was concentrated near the TPB.