Window gasketing for self humidified H2|O2 and H2 |air polymer electrolyte membrane fuel cells fed dry gases

Wayne L Gellett; Drew C Dunwoody; Johna Leddy

doi:10.1016/j.jelechem.2020.114695

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Window gasketing for self humidified H2|O2 and H2 |air polymer electrolyte membrane fuel cells fed dry gases

Journal article

Peer reviewed

Window gasketing for self humidified H2|O2 and H2 |air polymer electrolyte membrane fuel cells fed dry gases

Wayne L Gellett, Drew C Dunwoody and Johna Leddy

Journal of electroanalytical chemistry (Lausanne, Switzerland), Vol.875, p.114695

10/15/2020

DOI: 10.1016/j.jelechem.2020.114695

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Abstract

Polymer electrolyte fuel cells (PEFCs) are often formed with the cation exchange polymer Nafion® sandwiched between two electrodes and run on humidified H2 and O2 gases fed to electrodes held in tight gaskets. The tight gasket opening is only slightly wider than the electrodes. When run on dry H2 and O2, tight gasketed cells fail as water becomes imbalanced across the membrane. Here, the cathode is framed by a narrow perimeter washer so the cathode is centered in a generous Nafion window and surrounded by a thin (≈ 0.05 cm) reservoir volume. Unlike tight gasketed cells, water generated at the cathode crosses the large Nafion window to sustain self humidification at 0.522 V on dry H2 and O2 at 70, 37, and 25 oC and dry H2 and air at 37 oC for 1 atm pressure and moderate flow rates. Built from commercial components, window gasketed PEFCs provided stable, steady state current and power at 0.5 V for >170 h on dry H2 and oxidant. Tight gaskets always fail to yield self humidification whereas window gaskets enable effective self humidification on dry gases. A sketch is provided of how the Nafion window enhances water flux from the cathode. Because humidification hardware can be eliminated, window gasketed PEFCs may be especially useful in portable fuel cell systems. Submitted In Honor of Andrej Wieckowski. [Display omitted] •Self humidifying polymer electrolyte fuel cells run on dry H2 and dry O2 for > 170 h at 70, 37, and 25 oC.•A generous Nafion window frames the cathode to facilitate water transport from the cathode to sustain self humidification.•On dry H2 and O2 at 70 oC, the highest steady state power and current densities are 0.72 W cm−2 and 1.42 A cm−2 at 0.505 V.•Compared to tight gaskets at 70 oC on wet gas, power for window gaskets is comparable on dry gas and 30% higher on wet gas.•A simple sketch characterizes water flux from the cathode in window gasketed cells.

Dry gases

Nafion window gasket

Polymer electrolyte fuel cells

Self humidifying PEFC

Window gasketing

Details

Title: Subtitle: Window gasketing for self humidified H2|O2 and H2 |air polymer electrolyte membrane fuel cells fed dry gases
Creators: Wayne L Gellett
Drew C Dunwoody
Johna Leddy
Resource Type: Journal article
Publication Details: Journal of electroanalytical chemistry (Lausanne, Switzerland), Vol.875, p.114695
Publisher: Elsevier B.V
DOI: 10.1016/j.jelechem.2020.114695
ISSN: 1572-6657
eISSN: 1873-2569
Grant note: DOI: 10.13039/100000183, name: Army Research Office; DOI: 10.13039/100000001, name: National Science Foundation
Language: English
Date published: 10/15/2020
Academic Unit: Chemistry
Record Identifier: 9984216721902771

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