Synthesis of Poly (2,2′-(1,4-phenylene) 5,5′-bibenzimidazole) (para-PBI) and Phosphoric Acid Doped Membrane for Fuel Cells

Authors

  • S. Yu,

    1. Department of Chemistry and Biochemistry, USC NanoCenter, University of South Carolina, Columbia, SC 29208, USA
    2. Current address: BASF Fuel Cell, Inc., 39 Veronica Ave, Somerset, NJ 08873, USA
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  • H. Zhang,

    1. Department of Chemistry and Biochemistry, USC NanoCenter, University of South Carolina, Columbia, SC 29208, USA
    2. Current address: Hollingsworth & Vose, 5035 County Route 113, Easton, NY 12834, USA
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  • L. Xiao,

    1. Department of Chemistry and Biochemistry, USC NanoCenter, University of South Carolina, Columbia, SC 29208, USA
    2. Current address: Pall Corporation, 25 Harbor Park Drive North, Port Washington, NY 11050, USA
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  • E.-W. Choe,

    1. Department of Chemistry and Biochemistry, USC NanoCenter, University of South Carolina, Columbia, SC 29208, USA
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  • B. C. Benicewicz

    1. Department of Chemistry and Biochemistry, USC NanoCenter, University of South Carolina, Columbia, SC 29208, USA
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  • Paper presented at the MEA'08 Conference, La Grande Motte, 21st–24th September 2008

Abstract

A detailed investigation of the polymerisation conditions for poly(2,2′-(1,4-phenylene)5,5′-bibenzimidazole) (para-PBI) in polyphosphoric acid (PPA) led to the preparation of high molecular weight polymer. The polymer solutions could be used directly to produce phosphoric acid (PA)-doped PBI membranes by the PPA process. These membranes showed very high PA doping levels, i.e., up to ∼30 moles of PA per mole of PBI repeat unit. The ionic conductivity of the membranes was 0.24 S cm–1 at 160 °C. Fuel cell performance was measured at various operating conditions by changing temperature, pressure and gases and verified the high carbon monoxide (CO) tolerance of fuel cells operating at this temperature.

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