The membrane electrode assembly (MEA) is the core component of PEFCs. The MEA structure consists of two porous catalyst layers which are consisting of recast Nafion ionomer and the precious Pt metal catalyst nano particle sitting on the surface of carbon black aggregates. The Nafion� ionomer network in catalyst layer functions not only as a binder, but also as the necessary proton transport pathway.In our work, Nafion ionomer degradation in the catalyst layer has been investigated using a simulated process of a series of catalyst layers with different amounts of Nafion content to eliminate the influence from catalyst particles and membrane degradation. The degradation of the Nafion network in the catalyst layer was assumed to result in a shrunk Nafion network, which was simulated using a catalyst layer with a lower Nafion content. Catalyst layers with different Nafion content (A set of MEAs with different Nafion content from 28% to 12% was made by spray method) were fabricated and characterized for polarization curves and AC impedance for the H+conductivity to simulate the degradation of the Nafion ionomer network.The degradation of Nafion affected on performance and structure of the membrane electrode assembly (MEA). With the decrease of Nafion ionomer in catalyst layer, it was shown to have an effect on performance within the entire range of polarization curves, shown in Fig1.

Investigation of Nafion ionomer degradation in catalyst layer

246th National Meeting (2013)

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