Proton-conducting solid oxide fuel cells (H-SOFCs) with BaZr0.1Ce0.7Y0.2O3-delta (BZCY) electrolyte were fabricated by impregnating Sm0.5Sr0.5CoO3-delta (SSC) into La0.7Sr0.3FeO3-delta-BaZr0.1Ce0.7Y0.2O3-delta (LSF-BZCY) composite cathode. The X-ray diffraction analysis showed that SSC and LSF were chemically compatible, which verified the feasibility of SSC impregnation on the composite cathode. The SEM results exhibited that evenly distributed SSC nano-particles formed on the cathode surface and the amount of nano-particles increased with elevated SSC loading value. The electrochemical performances of the symmetrical and single cells were substantially improved by virtue of SSC impregnation. The long-term stability of impregnated single cell was also tested. The loading amount of 15 wt.% SSC after impregnation was proved to be the optimal value in improving the overall performance of BZCY electrolyte H-SOFCs with LSF-BZCY composite cathode. (C) 2015 Elsevier Ltd. All rights reserved.