Influence of heteropolyacid in enhancing proton conductivity of chitosan membranes for H2/O2 Fuel Cells

To promote Proton Exchange Membrane Fuel Cells(PEMFCs) commercialization, large research effort has beendevoted in developing new polymer electrolytes that canreplace the usually employed proton conductors, e.g. Nafion®,with other membranes of comparable performances but lowercost. Chitosan (CS)-based membrane electrolyte is currentlystudied as alternative candidate for PEMFC application.Several works have shown that Heteropolyacids (HPAs) can beused to prepare Chitosan polyelectrolytes (PECs) to beemployed as proton exchange membrane in low temperaturefuel cell. In previous works [1-3] we have shown that CS/PTAmembranes, prepared using alumina porous medium for theslow release of H3PW12O40, show good performances in H2fed fuel cell. Notably, in ref. [4] CS/PMA membranes arereported to exhibit proton conductivity higher than thatmeasured with CS/PTA. This paper in focused on the synthesisand characterization of CS/PMA and mixed CS/PMA-PTAmembranes with the aim to assess the influence of HPAconcentration and nature on their performance as protonconductors in H2 fed fuel cell. X-ray diffraction and FTIRanalyses were performed to study the structure andcomposition of the membranes, while SEM was used to getinformation on the membranes morphology and thickness as afunction of the preparation conditions. The membranes weretested in a H2/O2 fuel cell at room temperature. ImpedanceSpectroscopy was used to get information of the conductivity ofthe membrane and to model the overall electrical behaviour ofthe cell.