While cobalt-containing perovskite-type cathode materials facilitate the activation of oxygen reduction, they also suffer from problems like poor chemical stability in CO2, high thermal expansion coefficients, etc. Partial B site substitution with Fe element is expected to be able to mitigate these problems while keeping high catalyst performance. In this paper, a layered perovskite GdBaCoFeO5+delta (GBCF) was developed as a cathode material for protonic ceramic membrane fuel cells (PCMFCs) based on proton-conducting electrolyte of stable BaZr0.1Ce0.7Y0.2O3-delta (BZCY7). The button cells of Ni-BZCY7 vertical bar BZCY7 vertical bar GBCF were fabricated and tested from 600 to 700 degrees C with humidified H-2 (similar to 3% H2O) as a fuel and ambient oxygen as oxidant. An open-circuit potential of 1.002 V, maximum power density of 482 mW cm(-2), and a low electrode polarization resistance of 0.11 Omega cm(2) were achieved at 700 degrees C. The experimental results indicated that the layered perovskite GBCF is a good candidate for cathode material, while the developed Ni-BZCY7 vertical bar BZCY7 vertical bar GBCF cell is a promising functional material system for intermediate temperature solid oxide fuel cells. Published by Elsevier Ltd on behalf of Professor T. Nejat Veziroglu.