A cobalt-free Ba0.5Sr0.5FeO3-δ- Ce0.8Sm0.2O2-δ (BSF-SDC) composite is employed as a cathode for an anode-supported proton-conducting solid oxide fuel cells (H-SOFCs) using BaZr0.1Ce0.7Y0.2O 3-δ (BZCY) as the electrolyte. The chemical compatibility between BSF and SDC is evaluated. The XRD results show that BSF is chemically compatible with SDC after co-fired at 1000 °C for 6 h. A single cell with a 20-μm-thick BZCY electrolyte membrane exhibits excellent power densities as high as 792 and 696 mW cm-2 at 750 and 700 °C, respectively. To the best of our knowledge, this is the highest performance reported in literature up to now for BZCY-based single cells with cobalt-free cathode materials. Extremely low polarization resistances of 0.030 and 0.044 Ωcm2 are achieved at 750 and 700 °C respectively. The excellent performance implies that the cobalt-free BSF-SDC composite is a promising alternative cathode for H-SOFCs. Resistances of the tested cell are investigated under open circuit conditions at different operating temperatures by impedance spectroscopy. © 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.