Variations in interfacial properties during cell conditioning and influence of heat-treatment of ionomer on the characteristics of direct methanol fuel cells

Fuqiang Liu, Chao Yang Wang

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

Variations in interfacial properties in the anode catalyst layer during cell conditioning were characterized, and influence of the heat-treatment of ionomer on the characteristics of direct methanol fuel cells was investigated in this work. The anode catalyst layer was made by mixing a solvent-substituted Nafion solution with unsupported Pt/Ru black and curing the mixture in an oven with an inert environment. Materials characterization (SEM and optical microscopy) and electrochemical characterization (cell polarization, anode polarization, electrochemical impedance spectroscopy, and CO-stripping cyclic voltammetry) were performed. During cell conditioning, the enhanced kinetics of MeOH electrochemical oxidation and severe limiting current phenomenon are due to the combination of variations in interfacial properties and swelling of ionomer in the anode catalyst layer over time. Ru oxides at the catalyst surface are reduced continuously during cell conditioning. The nearly constant integrated areas under the CO-stripping CV peaks and broadened peak shapes indicate a stable number of Pt/Ru bimetallic alloy surface sites, yet the surface composition distribution is broadened. Heat-treatment influences ionomer crystallinity, altering its swelling behavior and hence affecting the characteristics of the direct methanol fuel cell (DMFC) anode.

Original languageEnglish (US)
Pages (from-to)1413-1422
Number of pages10
JournalElectrochimica Acta
Volume50
Issue number6
DOIs
StatePublished - Jan 1 2005

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Electrochemistry

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