Nafion/TiO2 proton conductive composite membranes for PEMFCs operating at elevated temperature and reduced relative humidity

Elena Chalkova, Michael B. Pague, Mark Valentinovich Fedkin, David J. Wesolowski, Serguei Lvov

Research output: Contribution to journalReview articlepeer-review

97 Scopus citations

Abstract

Nafion/TiO2 composite membranes with different TiO2 contents were studied in an H2/O2 proton exchange membrane fuel cell (PEMFC) over a wide range of relative humidity (RH) values from 26 to 100% at temperatures of 80 and 120°C. The composite membranes, which were prepared using a recast procedure, showed a pronounced improvement over unmodified Nafion membranes when operated at 120°C and reduced RH. For instance, at 50% RH, the Nafion/20% TiO2 membrane demonstrated a performance identical to that of an unmodified Nafion membrane operated at 100% RH. This performance level was comparable to that of a bare Nafion membrane at 80°C. The high performance of the Nafion/TiO2 composite membranes at low RH was attributed to improved water retention due to the presence of absorbed water species in the electrical double layer on the TiO2 surface. The zeta potential and thickness of the hydrodynamically immobile water layer at the TiO2/water interface were discussed as parameters influencing the water balance in the membranes. The obtained experimental PEMFC performance data were fitted using an analytical equation, and calculated parameters were analyzed as functions of RH and TiO2 content in the composite membranes.

Original languageEnglish (US)
JournalJournal of the Electrochemical Society
Volume152
Issue number6
DOIs
StatePublished - Aug 1 2005

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

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