Redox properties of La0.6Sr0.4Co0.2Fe0.8O3-? and Ba0.5Sr0.5Co0.8Fe0.2O3-? cathodes and effect of infiltration by La0.8Sr0.2MnO3-?

In this study, state-of-art La0.6Sr0.4Co0.2Fe0.8O3-? (LSCF) and Ba0.5Sr0.5Co0.8Fe0.2O3-? (BSCF) peroskites were investigated as cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs) and their behaviour under applied overpotential conditions was compared. The effect of wet infiltration by La0.8Sr0.2MnO3-? nano-sized discrete layer on performance and ageing effect was also analysed [1]. Electrochemical impedance spectroscopy (EIS) was applied to the cathode/Ce0.8Sm0.2O2-?- electrolyte system, to study the redox behaviour of the two different electrode phases. A decrease in polarization resistance for both LSCF- and BSCF-infiltrated electrodes was pointed out, compared to the reference ones, at open circuit voltage (OCV). Conversely, the application of cathodic overpotentials (-0.1 to -0.3 V) resulted in opposite effects on LSCF- and BSCF-based cathodes; calculation of the chemical capacitance highlighted a different response of the oxygen vacancies concentration to the applied voltage for the two perovskites compositions