Composite Membranes of PVDF Nanofibers Impregnated with Nafion for Increased Fuel Concentrations in Direct Methanol Fuel Cells

Serious methanol crossover of Nafion greatly limits the use of increased fuel concentrations in methanol fuel cells, which results in a decreased power density. To lower the methanol crossover of Nafion, thin layers of PVDF nanofibers were successfully electrospun and impregnated with a Nafion solution to create novel fuel cell membranes. The morphological structures, mechanical properties, thermal stabilities, chemical resistance and proton conductivity were investigated for each composite membrane. The performances of membranes with different layers of PVDF nanofibers were evaluated, using a single cell direct methanol fuel cell with 10M methanol fuel. In comparison with membranes of pure Nafion, the introduction of PVDF fiber mats greatly enhanced the membrane's thermal and oxidation stabilities, suppressed swelling ratios and water uptake, and increase fuel cell performance.