The Influence of Phosphoric Acid Migration on the Performance of High Temperature Polymer Electrolyte Fuel Cells

J Halter, S Thomas, S.K. Kær, T.J. Schmidt, F.N. Büchi

Research output: Contribution to journalJournal articleResearchpeer-review

6 Citations (Scopus)

Abstract

In high temperature polymer electrolyte fuel cells, phosphoric acid migration induces flooding of the anode gas diffusion layer at high current densities. The present study focuses on determining the influence of phosphoric acid flooding of the anode GDL on hydrogen mass transport limitations. Two methods for quantifying the performance losses at high current densities, related to acid migration, are discussed: anodic limiting current density measurements and electrochemical impedance spectroscopy. It is demonstrated that the limiting current measurements, the common method for determining transport resistances, is unable to detect the changes induced by acid migration, due to the transient time required when switching to the required low hydrogen concentrations, while EIS is able to capture the changes induced by acid migration because it is faster and less invasive. For diluted hydrogen, an increase of the transport resistance is measured, however the effect on the cell performance is negligible. The time constants for anode GDL flooding and de-flooding are determined based on the EIS data and found to be 8.1 ± 0.1 min for flooding and about 5.8 ± 0.9 min for de-flooding under the applied conditions.
Original languageEnglish
JournalJournal of Power Sources
Volume399
Pages (from-to)151-156
Number of pages6
ISSN0378-7753
DOIs
Publication statusPublished - Sep 2018

Fingerprint

phosphoric acid
Phosphoric acid
Electrolytes
fuel cells
Fuel cells
Hydrogen
Anodes
Polymers
Current density
electrolytes
Electric current measurement
Acids
anodes
polymers
current density
Phosphoric acid fuel cells (PAFC)
acids
high current
phosphoric acid fuel cells
hydrogen

Keywords

  • HT-PEFC
  • Mass transport resistance
  • Limiting current
  • EIS
  • Phosphoric acid migration

Cite this

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title = "The Influence of Phosphoric Acid Migration on the Performance of High Temperature Polymer Electrolyte Fuel Cells",
abstract = "In high temperature polymer electrolyte fuel cells, phosphoric acid migration induces flooding of the anode gas diffusion layer at high current densities. The present study focuses on determining the influence of phosphoric acid flooding of the anode GDL on hydrogen mass transport limitations. Two methods for quantifying the performance losses at high current densities, related to acid migration, are discussed: anodic limiting current density measurements and electrochemical impedance spectroscopy. It is demonstrated that the limiting current measurements, the common method for determining transport resistances, is unable to detect the changes induced by acid migration, due to the transient time required when switching to the required low hydrogen concentrations, while EIS is able to capture the changes induced by acid migration because it is faster and less invasive. For diluted hydrogen, an increase of the transport resistance is measured, however the effect on the cell performance is negligible. The time constants for anode GDL flooding and de-flooding are determined based on the EIS data and found to be 8.1 ± 0.1 min for flooding and about 5.8 ± 0.9 min for de-flooding under the applied conditions.",
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author = "J Halter and S Thomas and S.K. K{\ae}r and T.J. Schmidt and F.N. B{\"u}chi",
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The Influence of Phosphoric Acid Migration on the Performance of High Temperature Polymer Electrolyte Fuel Cells. / Halter, J; Thomas, S; Kær, S.K.; Schmidt, T.J.; Büchi, F.N.

In: Journal of Power Sources, Vol. 399, 09.2018, p. 151-156.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - The Influence of Phosphoric Acid Migration on the Performance of High Temperature Polymer Electrolyte Fuel Cells

AU - Halter, J

AU - Thomas, S

AU - Kær, S.K.

AU - Schmidt, T.J.

AU - Büchi, F.N.

PY - 2018/9

Y1 - 2018/9

N2 - In high temperature polymer electrolyte fuel cells, phosphoric acid migration induces flooding of the anode gas diffusion layer at high current densities. The present study focuses on determining the influence of phosphoric acid flooding of the anode GDL on hydrogen mass transport limitations. Two methods for quantifying the performance losses at high current densities, related to acid migration, are discussed: anodic limiting current density measurements and electrochemical impedance spectroscopy. It is demonstrated that the limiting current measurements, the common method for determining transport resistances, is unable to detect the changes induced by acid migration, due to the transient time required when switching to the required low hydrogen concentrations, while EIS is able to capture the changes induced by acid migration because it is faster and less invasive. For diluted hydrogen, an increase of the transport resistance is measured, however the effect on the cell performance is negligible. The time constants for anode GDL flooding and de-flooding are determined based on the EIS data and found to be 8.1 ± 0.1 min for flooding and about 5.8 ± 0.9 min for de-flooding under the applied conditions.

AB - In high temperature polymer electrolyte fuel cells, phosphoric acid migration induces flooding of the anode gas diffusion layer at high current densities. The present study focuses on determining the influence of phosphoric acid flooding of the anode GDL on hydrogen mass transport limitations. Two methods for quantifying the performance losses at high current densities, related to acid migration, are discussed: anodic limiting current density measurements and electrochemical impedance spectroscopy. It is demonstrated that the limiting current measurements, the common method for determining transport resistances, is unable to detect the changes induced by acid migration, due to the transient time required when switching to the required low hydrogen concentrations, while EIS is able to capture the changes induced by acid migration because it is faster and less invasive. For diluted hydrogen, an increase of the transport resistance is measured, however the effect on the cell performance is negligible. The time constants for anode GDL flooding and de-flooding are determined based on the EIS data and found to be 8.1 ± 0.1 min for flooding and about 5.8 ± 0.9 min for de-flooding under the applied conditions.

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