(510q) Nafion® Nanofibers And Their Effect On Polymer Electrolyte Membrane Fuel Cell Performance

Current fuel cell research is focused on reducing manufacturing costs by reducing platinum catalyst loading without sacrificing performance. Although improvements have been demonstrated by using platinum supported on porous carbon nanoparticles (Pt/C), significant losses in ?active? platinum surface area within the electrode or catalyst layer (CL) still occur. Optimizing the reactant gas/Nafion^®/platinum triple phase boundary (TPB) in the CL (i.e., CL morphology) will result in increased ?active? catalyst area and overall fuel cell performance. In this study, the effect of temperature on the formation of Nafion^® nanofibers in the CL during fuel cell operation and its subsequent improvement on fuel cell performance was clearly characterized. Post mortem scanning electron micrographs clearly show that Nafion^® nanofibers improve the TPB by increasing porosity, ?available? platinum surface area, while Nafion® nanofibers act as a more efficient proton transport route from the catalyst particles to the polymer electrolyte membrane. Further improvements to the TPB was demonstrated by fabricating Nafion^® nanofibers prior to fuel cell testing. These new CLs were developed by electrospinning a copolymer solution of Nafion^® and poly(acrylic acid) with catalyst particles (Pt/C) and also reducing Pt salts on electrospun Nafion^®/poly(acrylic acid) nanofibers. Micrographs confirm an improved TPB compared to standard CLs. The hydrogen fuel cell performance and optimization of these new nanofiber/nanoparticle CLs and their stability within a fuel cell will be presented.