Comparative study of electrochemical properties of different composite cathode materials associated to stable proton conducting BaZr0.7Pr0.1Y0.2O3-δ electrolyte

High-temperature proton conductor BaZr0.7Pr0.1Y0.2O3-δ (BZPY) was investigated as electrolyte for intermediate temperatures (400-800 °C) solid oxide fuel cells (IT-SOFCs), which exhibited excellent chemical stability in atmospheres containing CO2 and water vapor. In addition, both La0.4Sr0.6Co0.2Fe0.8O3-δ-BaZr0.7Pr0.1Y0.2O3-δ (LSCF-BZPY) and La0.4Sr0.6Co0.2Fe0.8O3-δ-Ce0.8Sm0.2O1.9 (LSCF-SDC) composite oxides were fabricated and evaluated as working cathodes for anode-supported IT-SOFCs based upon thin BZPY electrolytes. The single cells with LSCF-BZPY cathode showed the maximum power density of 86.7 mW cm−2 at 700 °C and the calculated activation energy was 91.19 kJ mol-1. While the cells with LSCF-SDC cathode exhibited the higher maximum power density of 112.4 mW cm−2 at 700 °C and the calculated activation energy was 101.61 kJ mol-1. The experimental results indicated that proton electron mixed conducting composite cathodes are more promising and beneficial than oxygen-ion electron mixed conducting composite cathodes for proton-conducting SOFCs during actual low operating temperatures.