Fuel cells were designed for high temperature operations. Poly [2,2'-(m-phenylene)-5,5'-bibenzimidazole] (PBI) was synthesized in a solution Of P2O5, CH3SO3H, and CF3SO3H. The PBI was dissolved in a mixture of CF3CO2H and H3PO4 and the solution was used for the preparation of Pt catalyst slurry for membrane electrode assembly. The single cell showed a current density of 280 mA (.) cm(-2) at a cell voltage of 0.5 V with feeds of H-2 and O-2 at 160 degreesC and without external humidification.