Polymer-zeolite composite membranes for direct methanol fuel cells

Authors

  • Brett Libby,

    1. Dept. of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455
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  • W. H. Smyrl,

    1. Dept. of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455
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  • E. L. Cussler

    Corresponding author
    1. Dept. of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455
    • Dept. of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455
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Abstract

Direct methanol fuel cells require membranes with the dual properties of high proton conductivity and low methanol crossover. Such membranes have a high selectivity, that is a high ratio of proton conductivity to methanol permeability. This research reports such a membrane made of polyvinylalcohol and loaded with mordenite, a proton conducting, methanol impermeable zeolite. Protons travel directly through both the polymer and zeolite phases, but methanol has a more tortuous path around the zeolite particles. The composite membranes show up to twenty times higher selectivity than Nafion, the current benchmark. The improved behavior, a result of the proper tailoring of the polymer and dispersion phase, is predicted using Maxwell's theory for diffusion in composite media.

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