Proton electrolyte membrane properties and direct methanol fuel cell performance - I. Characterization of hybrid sulfonated poly(ether ether ketone)/zirconium oxide membranes

V. S. Silva, B. Ruffmann, H. Silva, Y. A. Gallego, A. Mendes*, L. M. Madeira, Suzana Nunes

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

139 Scopus citations


This paper presents an evaluation of the zirconium oxide effects in sulfonated poly(ether ether ketone) (sPEEK) with sulfonation degree (SD) of 87%. A series of inorganic-organic hybrid membranes were prepared with a systematic variation of the zirconium oxide content via in situ zirconia formation (2.5, 5.0, 7.5, 10, 12.5 wt.%). This procedure enabled the preparation of proton electrolyte membranes (PEM) with a wide range of properties, which can be useful for evaluating the relationship between the PEM properties and the direct methanol fuel cell (DMFC) performance. The investigated properties are the proton conductivity, proton transport resistance, water uptake, water, methanol, oxygen, carbon dioxide and nitrogen permeability coefficients, morphology and elemental analysis. The results obtained show that the inorganic oxide network decreases the proton conductivity and water swelling. It is found that it leads also to a decrease of the water, methanol, carbon dioxide and oxygen permeability coefficients, an increase of the water/methanol selectivity and a decrease of the carbon dioxide/nitrogen and oxygen/nitrogen selectivities. In terms of morphology, it is found that in situ zirconium alkoxide hydrolysis enables the preparation of homogeneous membranes that present a good adhesion between inorganic domains and the polymer matrix.

Original languageEnglish (US)
Pages (from-to)34-40
Number of pages7
JournalJournal of Power Sources
Issue number1
StatePublished - Jan 1 2005


  • Direct methanol fuel cell
  • Morphology
  • Permeability coefficients
  • Sol-gel chemistry
  • Sulfonated poly(ether ether ketone) (sPEEK)
  • Zirconium oxide

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

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