Influence of practical operating temperature on the Cr poisoning for LSCF-GDC cathode

The influence of operating temperature on Cr poisoning effect on solid oxide fuel cells (SOFCs) cathode was comprehensive studied. The La0.6Sr0.4Co0.2Fe0.8O3-delta-Ce0.90Gd0.10O1.95 (LSCF-GDC) symmetric cells were investigated at 550, 600, 650, 700, 750 degrees C respectively in the presence of Crofer 22 APU. After aging in the air for 200 h, the cell operated at 650 degrees C expressed the most serious degradation. At the operating temperature lower than 650 degrees C, the degradation rate was accelerated with the increased operating temperature. At the operating temperature higher than 650 degrees C, the degradation rate slowed down with the increased operating temperature. Combined the experimental results with first principles calculation, the mechanism could be put forward that competition existed between the oxygen reduction reaction (ORR) activity and the formation reaction of SrCrO4. The activity of ORR and the formation of SrCrO4 at different operating temperatures codetermined the fluctuating degradation rate of LSCF-GDC cathode. This result could offer a valuable guidance for the rational application of LSCF-GDC cathode in SOFCs.