Electrochemical performance of (La,Sr)(Co,Fe)O3–(Ce,Gd)O3 composite cathodes

La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) and LSCF–Ce0.8Gd0.2O3 (GDC) composite cathodes on YSZ electrolytes were studied for potential applications in low-temperature solid oxide fuel cells (SOFCs). Impedance spectroscopy measurements were performed in oxygen partial pressures ranging from 10−3 to 1 atm over a temperature range from 500 to 750 °C. The LSCF electrodes yielded low-current interfacial resistance values that were a factor of 10 lower than for (La,Sr)MnO3 cathodes. The addition of 50 vol.% GDC to LSCF resulted in an additional factor of ≈10 decrease in the polarization resistance. Polarization resistance values for the LSCF–GDC cathodes were as low as 0.01 Ω cm2 at 750 °C and 0.33 Ω cm2 at 600 °C.