Nanocomposite fuel cell membranes based on Nafion and acid functionalized zeolite beta nanocrystals

We have prepared nanocomposite proton exchange membranes (PEMs) based on Nafion with sulfonic acid functionalized zeolite beta (AFB) as an additive. 2.5 and 5 wt% AFB composite membranes possess proton conductivity/methanol permeability (selectivity) ratios as much as 93% higher than commercial Nallon 117 at 21 degrees C, and 63% higher at 80 degrees C. These 2.5 and 5wt% AFB composite membranes also outperform commercial Nafion 117 in direct methanol fuel cell performance evaluations. The composite membranes are characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, four-electrode impedance for proton conductivity, two-compartment permeation for methanol crossover, and direct methanol fuel cell performance. (C) 2008 Elsevier B.V. All rights reserved.