Modified Sulfonated Poly(ether ether ketone) Based Mixed Matrix Membranes for Direct Methanol Fuel Cells

Mixed matrix membranes based on zeolite 4A-methane sulfonic acid (MSA)-sulfonated poly(ether ether ketone) (SPEEK) are evaluated as a potential polymer electrolyte membrane (PEM) for direct methanol fuel cells (DMFCs). Ion-exchange capacity, sorption of water, and water-methanol mixture, proton conductivity, and methanol permeability for the mixed-matrix membranes have been extensively investigated. The mixed-matrix membranes are also characterized for their cross-sectional morphology, mechanical, and thermal properties. DMFCs employing SPEEK-MSA (20wt.%) blend, zeolite 4A (4wt.%)-SPEEK-MSA (20wt.%) mixed matrix membranes deliver peak power densities of 130 and 159mWcm(-2), respectively; while a peak power density of only 95mWcm(-2) is obtained for the DMFC employing pristine SPEEK membrane at 70 degrees C. The results showed that these SPEEK based mixed matrix membranes exhibit higher DMFC performance and lower methanol permeability in comparison to Nafion-117 membrane.