Characterization of a monolithic mesoporous carbon as diffusion layer for micro fuel cells application

The preparation and characterization of a monolithic mesoporous carbon structure, which could be used as diffusion layer in PEM and DMPEM micro fuel cells, is described. Several characteristics of the monolithic carbon were studied, such as specific surface area, pore size distribution, bulk electrical resistivity, contact resistance with graphite plates, along with the wettability, imbibition and permeability of methanol aqueous solution. These properties were compared to those reported for commercial carbon paper and carbon cloth materials commonly used as diffusion layers in PEM fuel cells. The electrical properties of the mesoporous carbon meet the requirements to be employed as diffusion layers in PEM stacks assembled at pressures above 15 bar. The rapid spreading and imbibition of concentrated methanol solutions in the mesoporous carbon, as well as the permeability of the aqueous methanol through it, also make this mesostructured carbon a possible candidate for diffusion layer and catalyst support in passive direct methanol micro fuel cells.

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► Mesoporous carbon with high specific area as diffusion layer in PEM and DMPEM.
► Resistivity is lower than the through-plane resistivity of commercial GDL.
► Contact resistance with graphite is remarkable low at pressures above 20 bar.
► The spreading and imbibition of concentrated methanol solutions is very rapid.
► Permeability of aqueous methanol is adequate for passive DM micro fuel cells.