PBI-based composite membranes for polymer fuel cells

In the present study poly(2,2-(2,6-pyridin)-5,5-bibenzimidazole) was used for the preparation of novelMEAs for high-temperature polymer fuel cells (HT-PEMFCs). We prepared hybrid materials with twotypes of silica fillers in order to increase the MEA performances using this polymer. The membranes werecharacterized in terms of their microstructure and thermal stability. Cell operation tests and ElectrochemicalImpedance Spectroscopy were used for the characterization of the MEAs. A maximum powerdensity of about 80mWcm−2 was obtained at 300mAcm−2 by using an imidazole-modified silica filler.The EIS technique showed that the fillers chiefly help to reduce the charge transfer resistance of thecathodic side. The gas transfer resistance may be neglected with respect to Rct, at least at low currentdensities.