Complex capacitance analysis of ionic resistance and interfacial capacitance in PEMFC and DMFC catalyst layers

Jong Hyun Jang, Sunyeol Jeon, Jae Hyung Cho, Soo Kil Kim, Sang Yeop Lee, Eunae Cho, Hyung Juhn Kim, Jonghee Han, Tae Hoon Lim

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

For polymer electrolyte membrane fuel cell (PEMFC) and direct methanol fuel cell (DMFC) catalyst layers (CLs), a complex capacitance analysis of impedance data was developed to evaluate the catalyst/ionomer interfacial capacitance and ionic resistance of ionomer networks without nonlinear data fitting. First, assuming no faradaic reactions, equivalent circuits for the CLs were suggested, which are similar to electric double-layer capacitor systems with porous carbon electrodes. Then, with the simulated complex capacitances, it was confirmed that the plots of the real and imaginary parts as a function of ac frequency are determined by the catalyst/ionomer interfacial capacitances and the ionic resistances time constants, which are important characteristics for high fuel cell performances. Experimentally, the condition of no faradaic reactions was realized by supplying nitrogen or water to the cathodes instead of air and by fixing the dc potential at 0.4 V during the impedance measurements. By performing a complex capacitance analysis, the interfacial capacitances and ionic resistances of PEMFC membrane electrode assemblies (MEAs) can be obtained at various relative humidities, proving that the catalytic activity in fuel cell operation depends on ionic resistances as well as on the catalyst/ionomer interfacial area. The effects of various MEA preparation methods on the ionomer distributions and DMFC performances were analyzed by a complex capacitance analysis.

Original languageEnglish
JournalJournal of the Electrochemical Society
Volume156
Issue number11
DOIs
Publication statusPublished - 2009 Oct 13
Externally publishedYes

Fingerprint

Direct methanol fuel cells (DMFC)
electrocatalysts
Proton exchange membrane fuel cells (PEMFC)
fuel cells
Ionomers
Capacitance
methyl alcohol
capacitance
electrolytes
membranes
Catalysts
polymers
catalysts
assemblies
Electrodes
electrodes
Fuel cells
Nonlinear networks
supplying
electrochemical capacitors

ASJC Scopus subject areas

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

Cite this

Complex capacitance analysis of ionic resistance and interfacial capacitance in PEMFC and DMFC catalyst layers. / Jang, Jong Hyun; Jeon, Sunyeol; Cho, Jae Hyung; Kim, Soo Kil; Lee, Sang Yeop; Cho, Eunae; Kim, Hyung Juhn; Han, Jonghee; Lim, Tae Hoon.

In: Journal of the Electrochemical Society, Vol. 156, No. 11, 13.10.2009.

Research output: Contribution to journalArticle

Jang, Jong Hyun ; Jeon, Sunyeol ; Cho, Jae Hyung ; Kim, Soo Kil ; Lee, Sang Yeop ; Cho, Eunae ; Kim, Hyung Juhn ; Han, Jonghee ; Lim, Tae Hoon. / Complex capacitance analysis of ionic resistance and interfacial capacitance in PEMFC and DMFC catalyst layers. In: Journal of the Electrochemical Society. 2009 ; Vol. 156, No. 11.
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