Single-step fabrication of a Poly(2,5-benzimidazole) (ABPBI)-based gas diffusion electrode (GDE) by directly adding a carbon-supported-catalyst to a homogeneous ABM solution prior to deposition and its membrane electrode assembly (MEA) were investigated for high-temperature proton exchange membrane (PEM) fuel cell applications. The ABPBI and LiCl dosages of the catalyst layer were varied. The characterizations of the resulting electrodes and/or MEA for the gas permeability, electrical resistance, specific electrochemical surface area, AC impedance, cyclic voltammetry and high-temperature PEM fuel cell performance were carried out. The high-temperature PEM fuel cell was successfully demonstrated at temperatures of up to 180 degrees C under ambient pressure operation. The fuel cell performance was evaluated by using dry hydrogen/oxygen gases, which added the advantage of eliminating the complicated humidification system of Nafion cells. The obtained results revealed that a catalyst layer with an ABPBI content of 15 wt.% and an ABPBI/LiCl ratio of 1:2 was sufficient to obtain the optimal cell performance with better electrochemical properties of low cell impedance, high electrochemical activity, low contact resistance and short activation time. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.