The layered perovskite structure oxide NdBaCo2O5+delta (NBCO) with rapid oxygen ion diffusion and surface exchange kinetics was synthesized by auto ignition process and initially examined as a cathode for proton-conducting fuel cells (H-SOFCs). The single cell, consisting of NdBaCo2O5+delta (NBCO)/BaZr0.1Ce0.7Y0.2O3-delta (BZCY)/NiO-BaZr0.1Ce0.7Y0.2O3-delta (BZCY) structure, was assembled and tested from 650 to 700 degrees C with humidified hydrogen (similar to 3% H2O) as the fuel and air as the oxidant. A maximum power density of 438 MW cm(-2) at 700 degrees C was obtained for the single cell and electrochemical performance of the cell was studied. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.