A cobalt-free Ba0.5Sr0.5Fe0.9Ni0.1O3-delta-Sm0.2Ce0.8O1.9 (BSFN-SDC) composite was employed as a cathode for proton-conducting solid oxide fuel cells (H-SOFCs) using BaZr0.1Ce0.7Y0.2O3-delta (BZCY) as the electrolyte. The chemical compatibility between BSFN and SDC was evaluated. The XRD results showed that BSFN was chemically compatible with SDC after co-fired at 1100 degrees C for 5 h. The thermal expansion coefficient (TEC) of BSFN-SDC, which showed a reasonably reduced value (16.08 x 10(-6) K-1), was effectively decreased due to Ce0.8Sm0.2O1.9 (SDC) added. A single cell of Ni-BZCY/Ni-BZCY/BZCY/ BSFN-SDC with a 25-mu m-thick BZCY electrolyte membrane exhibited excellent power densities as high as 361.8 mW cm(-2) at 700 degrees C with a low polarization resistance of 0.174 Omega cm(2). The excellent performance implied that the cobalt-free BSFN-SDC composite was a promising alternative cathode for H-SOFCs. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.