Synthesis and properties of ceramics-polymer composite membranes as high temperature proton conducting electrolytes

Proton-conducting inorganic/organic composite membranes, which were mechani cally flexible, were fabricated, and their conduction properties were chara cterised for use as polymer electrolyte fuel cells (PEFCs) operating at rel atively higher temperatures (100 similar to 150 degrees C). SiO2/PEO (polye thylene oxide) membranes doped with acidic molecules (monododecylphosphate) were fabricated by using the sol-gel route, and the proton conductivities were measured using impedance spectroscopy. The composite electrolytes show ed reasonable electrical-conductivity values (10(-3)similar to 10(-4) S/cm) up to 150 degrees C and differential thermal analysis and thermogravimetri c analysis (DTA/TG) data showed that the membranes were thermally stable up to 350 degrees C, possibly due to the SiO2 backbone framework.