High temperature transport properties of polyphosphazene membranes for direct methanol fuel cells

Xiangyang Zhou, Jamie Weston, Elena Chalkova, Michael A. Hofmann, Catherine M. Ambler, Harry R. Allcock, Serguei N. Lvov

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101 Scopus citations

Abstract

Experimental methods for studying the conductivity and methanol permeability of proton conductive polymers over a wide range of temperatures have been developed. The proton conductivity and methanol permeability of several polymer electrolyte membranes including sulfonated and phosphonated poly[(aryloxy)phosphazenes] was determined at temperatures up to 120 °C. Nafion 117 membranes were tested using the same methods in order to determine the reliability of the methods. Although the conductivities of the polyphosphazene membranes were either similar to or lower than that of the Nafion 117 membranes, they continue to hold promise for fuel cell applications. We observed similar activation energies of proton conduction for Nafion 117, and for sulfonated and phosphonated polyphosphazene membranes. However, the methanol permeability of a sulfonated membrane was about 8 times lower than that of the Nafion 117 membrane at room temperature although the values were comparable at 120 °C. The permeability of a phosphonated phosphazene derivative was about 40 times lower than that of the Nafion 117 membrane at room temperature and about 9 times lower at 120 °C. This is a significant improvement over the behavior of Nafion 117.

Original languageEnglish (US)
Pages (from-to)2173-2180
Number of pages8
JournalElectrochimica Acta
Volume48
Issue number14-16 SPEC.
DOIs
StatePublished - Jun 30 2003

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Keywords

  • Conductivity
  • Direct methanol fuel cell
  • High temperature
  • Methanol permeability
  • Polyphosphazene membrane

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Analytical Chemistry
  • Electrochemistry

Cite this

Zhou, X., Weston, J., Chalkova, E., Hofmann, M. A., Ambler, C. M., Allcock, H. R., & Lvov, S. N. (2003). High temperature transport properties of polyphosphazene membranes for direct methanol fuel cells. Electrochimica Acta, 48(14-16 SPEC.), 2173-2180. https://doi.org/10.1016/S0013-4686(03)00201-9