Organic-inorganic hybrid composite membranes have been prepared and evaluated for polymer electrolyte membrane fuel cells (PEMFCs) at 100-140 degrees C. A series of synthesized poly (fluorinated arylene ether)s was sulfonated by fuming sulfuric acid (20% SO3). The zirconium phosphate composite membrane was prepared by soaking the sulfonated poly (fluorinated arylene ether)s stepwise in 1 M zirconyl chloride solution and 1 M phosphoric acid solution. The chemical, thermal, and electrochemical properties of the composite membrane were investigated by thermogravimetric analysis (TGA), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), and unit cell test. The cell performance of the zirconium phosphate sulfonated poly (fluorinated arylene ether)s composite membrane was superior to that of the starting membrane at intermediate temperature, 100-140 degrees C. And the cell performance with composite membrane indicated stable behavior during experimentation when operating temperature maintained at 120 degrees C, whereas sulfonated poly (fluorinated arylene ether)s membrane was irreversible degradation under the same condition. (c) 2006 Elsevier Ltd. All rights reserved.