A stable, easily sintered perovskite oxide BaCe0.5Zr0.3Y0.16Zn0.04O3-delta (BCZYZn) as an electrolyte for protonic ceramic mernbrane fuel cells (PCMFCs) with Ba0.5Sr0.5Zn0.2Fe0.8O3-delta (BSZF) perovskite cathode was investigated. The BCZYZn perovskite electrolyte synthesized by a modified Pechini method exhibited higher sinterability and reached 97.4% relative density at 1200 degrees C for 5 h in air, which is about 200 degrees C lower than that without Zn dopant. By fabricating thin membrane BCZYZn electrolyte (about 30 mu m in thickness) on NiO-BCZYZn anode support, PCMFCs were assembled and tested by selecting stable BSZF perovskite cathode. An open-circuit potential of 1.00V, a maximum power density of 236 mWcm(-2), and a low polarization resistance of the electrodes of 0.17 Omega cm(2) were achieved at 700 degrees C. This investigation indicated that proton conducting electrolyte BCZYZn with BSZF perovskite cathode is a promising material system for the next generation solid oxide fuel cells. (C) 2008 Elsevier B.V. All rights reserved.