Solid oxide fuel cells (SOFCs) have attracted tremendous attention for their combination of environmental power generation and fuel flexibility. Proton conducting SOFCs (P-SOFCs) demonstrate advantages over oxygen-ion conducting SOFCs, such as less activation energies on ionic transport and higher fuel utilization efficiency. Central to the devices is a suitable cathode with high catalytic activity. Herein, a cubic perovskite BaCo0.7Fe0.22Sc0.08O3-delta (BCFSc) has been applied as the cathode in proton-conducting solid state fuel cell (SOFC) with BaZr0.1Ce0.7Y0.2O3-delta (BZCY) electrolyte. Peak power densities of 760, 591, 452 and 318 mW cm(-2) are obtained at 650, 600, 550 and 500 degrees C with humidified hydrogen as the fuel and air as the oxidant. A low polarization resistance of 0.05 Omega cm(2) under open circuit at 650 degrees C is observed. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.