---
_id: '7325'
abstract:
- lang: eng
text: 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.
article_number: B383
article_processing_charge: No
article_type: original
author:
- first_name: I. A.
full_name: Schneider, I. A.
last_name: Schneider
- first_name: Stefan Alexander
full_name: Freunberger, Stefan Alexander
id: A8CA28E6-CE23-11E9-AD2D-EC27E6697425
last_name: Freunberger
orcid: 0000-0003-2902-5319
- first_name: D.
full_name: Kramer, D.
last_name: Kramer
- first_name: A.
full_name: Wokaun, A.
last_name: Wokaun
- first_name: G. G.
full_name: Scherer, G. G.
last_name: Scherer
citation:
ama: 'Schneider IA, Freunberger SA, Kramer D, Wokaun A, Scherer GG. Oscillations
in gas channels: Part I. The forgotten player in impedance spectroscopy in PEFCs.
Journal of The Electrochemical Society. 2007;154(4). doi:10.1149/1.2435706'
apa: 'Schneider, I. A., Freunberger, S. A., Kramer, D., Wokaun, A., & Scherer,
G. G. (2007). Oscillations in gas channels: Part I. The forgotten player in impedance
spectroscopy in PEFCs. Journal of The Electrochemical Society. The Electrochemical
Society. https://doi.org/10.1149/1.2435706'
chicago: 'Schneider, I. A., Stefan Alexander Freunberger, D. Kramer, A. Wokaun,
and G. G. Scherer. “Oscillations in Gas Channels: Part I. The Forgotten Player
in Impedance Spectroscopy in PEFCs.” Journal of The Electrochemical Society.
The Electrochemical Society, 2007. https://doi.org/10.1149/1.2435706.'
ieee: 'I. A. Schneider, S. A. Freunberger, D. Kramer, A. Wokaun, and G. G. Scherer,
“Oscillations in gas channels: Part I. The forgotten player in impedance spectroscopy
in PEFCs,” Journal of The Electrochemical Society, vol. 154, no. 4. The
Electrochemical Society, 2007.'
ista: 'Schneider IA, Freunberger SA, Kramer D, Wokaun A, Scherer GG. 2007. Oscillations
in gas channels: Part I. The forgotten player in impedance spectroscopy in PEFCs.
Journal of The Electrochemical Society. 154(4), B383.'
mla: 'Schneider, I. A., et al. “Oscillations in Gas Channels: Part I. The Forgotten
Player in Impedance Spectroscopy in PEFCs.” Journal of The Electrochemical
Society, vol. 154, no. 4, B383, The Electrochemical Society, 2007, doi:10.1149/1.2435706.'
short: I.A. Schneider, S.A. Freunberger, D. Kramer, A. Wokaun, G.G. Scherer, Journal
of The Electrochemical Society 154 (2007).
date_created: 2020-01-15T12:22:31Z
date_published: 2007-02-09T00:00:00Z
date_updated: 2021-01-12T08:13:05Z
day: '09'
doi: 10.1149/1.2435706
extern: '1'
intvolume: ' 154'
issue: '4'
language:
- iso: eng
month: '02'
oa_version: None
publication: Journal of The Electrochemical Society
publication_identifier:
issn:
- 0013-4651
publication_status: published
publisher: The Electrochemical Society
quality_controlled: '1'
status: public
title: 'Oscillations in gas channels: Part I. The forgotten player in impedance spectroscopy
in PEFCs'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 154
year: '2007'
...