Intermediate-to-low temperature protonic ceramic membrane fuel cells with Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ-BaZr_0.1Ce_0.7Y_0.2O_3-δ composite cathode

The perovskite-type Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ-BaZr_0.1Ce_0.7Y_0.2O_3-δ (BSCF-BZCY) composite oxides were synthesized by a modified Pechini method and examined as a novel composite cathode for intermediate-to-low temperature protonic ceramic membrane fuel cells (ILT-PCMFCs). Thin proton-conducting BaZr_0.1Ce_0.7Y_0.2O_3-δ (BZCY) electrolyte and NiO-BaZr_0.1Ce_0.7Y_0.2O_3-δ (NiO-BZCY) anode functional layer were prepared over porous anode substrates composed of NiO-BaZr_0.1Ce_0.7Y_0.2O_3-δ by a one-step dry-pressing/co-firing process. A laboratory-sized quad-layer cell of NiO-BZCY/NiO-BZCY(∼50 μm)/BZCY(∼20 μm)/BSCF-BZCY(∼50 μm) was operated from 550 to 700 °C with humidified hydrogen (∼3% H₂O) as fuel and the static air as oxidant. A high open-circuit potential of 1.009 V, a maximum power density of 418 mW cm^-2, and a low polarization resistance of the electrodes of 0.10 Ω cm² was achieved at 700 °C. These investigations have indicated that proton-conducting BZCY electrolyte with BSCF perovskite cathode is a promising material system for the next generation solid oxide fuel cells (SOFCs).