Proton-conducting solid oxide fuel cells. incorporating BaZr0.1Ce0.7Y0.2O3-delta (BZCY) electrolyte, NiO-BZCY anode, and Sm0.5Sr0.5CoO3-delta-Ce0.8Sm0.2O2-delta (SSC-SDC) cathode, were successfully fabricated by a combined co-pressing and printing technique after a one-step co-firing process at 1100, 1150, or 1200 degrees C. Scanning electron microscope (SEM) results revealed that the co-firing temperature significantly affected not only the density of the electrolyte membrane but the grain size and porosity of the electrodes. Influences of the co-firing temperature on the electrochemical performances of the single cells were also studied in detail. Using wet hydrogen (2% H2O) as the fuel and static air as the oxidant, the cell co-fired at 1150 degrees C showed the highest maximum power density (PDmax) of 552 and 370 mW cm(-2) at 700 and 650 degrees C, respectively, while the one co-fired at 1100 degrees C showed the highest PDmax of 276 and 170 mWcm(-2) at 600 and 550 degrees C. respectively. The Arrhenius equation was proposed to analyze the dependence of the PDmax on the operating temperature, and revealed that PDmax of the cell co-fired at a lower temperature was less dependent on operating temperature. The influences of the co-firing temperature on the resistances of the single cells, which were estimated from the electrochemical impedance spectroscopy measured under open circuit conditions, were also investigated. (C) 2010 Elsevier Ltd. All rights reserved.