A correct water management is at the basis of the design of more performing PEM fuel cells, especially by avoiding the flooding of cathode and minimizing mass transfer limitations. Gas diffusion layer (GDL) results as critical component for reaching this target and the most effective approaches are actually based on dual-layer GDLs, i.e. a carbon black (CB) layer on a sheet of macroporous carbon cloth (CC) or carbon paper (CP). The wettability of these carbon-based materials is modified by hydrophobic treatments: e.g. CCs or CPs are usually hydrophobized with fluoropolymers such as polytetrafluoroethylene (PTFE) and CB powder is mixed with aqueous dispersion of colloidal PTFE particles. However, the use of solid fluoropolymers causes poor gas transport and high electric resistance.Gas permeability as well as thermooxidative stability represents the main characteristic of perfluoropolyethers (PFPEs) and highly hydrophobic PFPE chains can be covalently bonded to carbon-based materials by the thermal decomposition of PFPE peroxides.[1]The functionalization of CC and conductive CB with PFPE moieties was performed without any molecular spacer that could decrease both thermal and chemical stabilities of the resulting materials and, as a result, the carbon-based materials became superhydrophobic, maintaining their electrical conductivity.[2]GDLs were prepared with PFPE-modified carbon-based materials and they were tested in a fuel cell at two operating temperatures, 60�C and 80�C, with 80/60% and 80/100% relative humidity (RH) of the inlet gases. The tests revealed that GDLs based on PFPE-modified materials overall performed better than standard PTFE-hydrophobized GDLs.References1)  Maurizio Sansotera, Walter Navarrini, Massimo Gola, Giovanni Dotelli, Paola Gallo Stampino, Claudia L. Bianchi, Int. J. Hydrogen Energ., 37 , 6277-6284 (2012).2)  Massimo Gola, Maurizio Sansotera, Walter Navarrini, Claudia L. Bianchi, Paola Gallo Stampino, Saverio Latorrata, Giovanni Dotelli, J. Power Sources, (2014), DOI: http://dx.doi.org/10.1016/j.jpowsour.2014.02.025.

Perfluoropolyether-modified carbon-based materials for proton exchange membrane fuel cells

248th National Meeting (2014)

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