A novel single phase BaCe(0.5)Bi(0.5)O(3) (- delta) (BCB) was employed as a cathode material for a proton-conducting solid oxide fuel cell (SOFC). The single cell, consisting of a BaZr(0.1)Ce(0.7)Y(0.2)O(3 - delta) (BZCY7)-NiO anode substrate, a BZCY7 anode functional layer, a BZCY7 electrolyte membrane and a BCB cathode layer, was assembled and tested from 600 to 700 degrees C with humidified hydrogen (similar to 3% H(2)O) as the fuel and the static ir as the oxidant. An open-circuit potential of 0.96 V and a maximum power density of 321 mW cm(-2) were obtained for the single cell. A relatively low interfacial polarization resistance of 0.28 Omega cm(2) at 700 degrees C indicated that the BCB was a promising cathode material for proton-conducting SOFCs. (C) 2009 Elsevier B.V. All rights reserved.