Evaluation of the Cathode Performance and the Distribution of Deposited Cr Species in the LSCF6428 Cathode by Cr Poisoning

The Cr poisoning behavior of LSCF6428 cathode was investigated under Cr-containing vapor conditions at 1073 K using LSCF6428/GDC/Pt cells. When exposed to the Cr-containing vapor, the polarization resistance (low frequency contribution) evaluated from the fitting results of AC impedance measurements of the samples was significantly increased. The sample operated under polarization condition for a longer time (380 h) had higher Cr concentration and lower Sr concentration inside the LSCF cathode, but its resistance was lower compared to the sample operated for a shorter time (75 h) under OCV condition. Microstructural and compositional analysis of the samples operated under polarization condition revealed a significant change in microstructure related to Sr transport. The detailed concentration of Cr and Sr inside the porous LSCF cathode was quantitatively measured by secondary ion mass spectrometer (SIMS), from which the distributions of Cr and Sr inside the porous LSCF cathode after Cr poisoning were derived.