Sulfur Poisoning on La0.6Sr0.4Co0.2Fe0.8O3 Cathode for SOFCs

The effect of SO 2 content in air on degradation of a La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF6428) cathode for solid oxide fuel cells was investigated at T = 1073 K for 24 h by setting the concentration of SO 2 to 0.1, 1, 10, and 100 ppm. The degradation of the LSCF6428 cathode became more significant with increasing SO 2 concentrations due to the increase of cathode polarization resistance. The SrSO 4 formation was confirmed after exposing to SO 2 from 0.1 to 100 ppm and became even harsh with increasing SO 2 concentrations. The reaction sequence can be interpreted from thermodynamic considerations using chemical potential diagrams and chemical equilibrium calculations.