Fuel cell performances at intermediate temperature 600 degrees C were examined for the hydrogen membrane fuel cell (HMFC) designed by rf sputter deposition of a BaCe0.8Y0.2O3-delta thin film electrolyte (1 mu m thickness) on a Pd1-xAgx (x = 0, 0.2 and 0.4) solid anode. The maximum power density reached to 1.2 W cm(-2) at 600 degrees C with the Pd0.8Ag0.2 anodes, and this value was much higher than the champion data of the recent anode-supported proton-conducting ceramic fuel cells (PCFCs). By electrochemical impedance analysis, it was demonstrated that the hydrogen permeability was crucial to the anode polarization losses of the HMFC because the charge transfer resistances and concentration overpotentials at BaCe0.8Y0.2O3-delta/Pd oxide-metal interfaces are simultaneously improved with the alloys having higher hydrogen permeability. (C) 2017 The Electrochemical Society. All rights reserved.