Development of Charge-Transfer Complex Hybrid Films as Polymer Electrolyte Membrane for High Temperature PEFC Operation

Novel charge-transfer (CT) complex hybrid films for high temperature polymer electrolyte fuel cell (PEFC) application based on sulfonated polyimide (SPI) with hydrophobic unit (4,4 (sulfonylbis(4,1-phenylene)bis(oxy)dianyline (BAPPS)) are synthesized and characterized. In this study, property changes of the polymer electrolytes prepared by a unique CT complex postmodification process are evaluated. The effect of the CT complex formation in the obtained films on the properties of the polymer films is evaluated, because the CT complex can work as a binder between SPIs. Water uptake of the CT complex hybrid films shows a lower value than that of the original SPI film. The CT complex hybrid films also exhibit comparable proton conductivity to Nafion 115 under high-temperature operational conditions (100-120 degrees C). These results suggest that the CT complex hybrid films developed are promising alternatives for high temperature PEFC application.