---
res:
  bibo_abstract:
  - Our experimental results shown here disprove that finite diffusion can generally
    be assumed in ac impedance models for H2/air-polymer electrolyte fuel cells (PEFCs)
    to account for the diffusive transport of oxygen through the gas diffusion layer
    (GDL) toward the air electrode. It is shown that the amplitude of the oxygen concentration
    oscillation created as a consequence of superimposed ac current at the air electrode
    is not zero at the channel/GDL interface but extends into the gas channels, at
    least below modulation frequencies of fmod=10 Hz . By this, sinusoidal oxygen-concentration
    oscillations within the cathode gas channels are excited locally along the flow
    field. Due to the forced air convection in the cathode flow-field channels, a
    coupling via the gas phase occurs downstream of the flow field. The coupling strongly
    affects the local and by this the overall impedance response of the cell and evokes
    the formation of a low-frequency arc in H2/air-PEFC impedance spectra. Based on
    the experimental results, a qualitative model is presented explaining the local
    impedance response of a segmented 200cm2H2/air PEFC.@eng
  bibo_authorlist:
  - foaf_Person:
      foaf_givenName: I. A.
      foaf_name: Schneider, I. A.
      foaf_surname: Schneider
  - foaf_Person:
      foaf_givenName: Stefan Alexander
      foaf_name: Freunberger, Stefan Alexander
      foaf_surname: Freunberger
      foaf_workInfoHomepage: http://www.librecat.org/personId=A8CA28E6-CE23-11E9-AD2D-EC27E6697425
    orcid: 0000-0003-2902-5319
  - foaf_Person:
      foaf_givenName: D.
      foaf_name: Kramer, D.
      foaf_surname: Kramer
  - foaf_Person:
      foaf_givenName: A.
      foaf_name: Wokaun, A.
      foaf_surname: Wokaun
  - foaf_Person:
      foaf_givenName: G. G.
      foaf_name: Scherer, G. G.
      foaf_surname: Scherer
  bibo_doi: 10.1149/1.2435706
  bibo_issue: '4'
  bibo_volume: 154
  dct_date: 2007^xs_gYear
  dct_isPartOf:
  - http://id.crossref.org/issn/0013-4651
  dct_language: eng
  dct_publisher: The Electrochemical Society@
  dct_title: 'Oscillations in gas channels: Part I. The forgotten player in impedance
    spectroscopy in PEFCs@'
...