Bulk modification of Nafion® with purple membrane for direct methanol fuel cell applications

Novel methanol-blocking polymer electrolyte composite membranes were prepared by inserting purple membrane (PM) to the bulk phase of Nafion® resin. Results of scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) analyses show that PM was well-dispersed in Nafion® membrane. Compared with recast Nafion®, blending PM changed the microstructure of Nafion® membrane and significantly improved the methanol-blocking efficiency by 31.6% in maximum. With PM content of 0.3 wt% in the composite, the highest membrane selectivity factor and single cell power density of 62.1 mW cm−2 were achieved. This satisfactory cell performance has given a promising prospect of Nafion®/PM composite membranes in the application in DMFC.

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► The biomaterial purple membrane was inserted to the Nafion® resin to fabricate the Nafion®/PM composite membranes.
► Nafion®/PM exhibits effective methanol-blocking and maintains the relatively high proton conductivity under low PM content (<1%).
► The Nafion®/PM composite membrane with specific PM content outputs desirable power density.