Understanding water dynamics in operating fuel cells by operando neutron tomography: investigation of different flow field designs
Water management plays a key role in ensuring optimum polymer electrolyte fuel cell (PEFC) performance, and flow field design can influence the ability of a cell to balance maintaining hydration, whilst avoiding flooding and cell failure. This work deepens the understanding of water evolution in dif...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2024-01-01
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| Series: | JPhys Energy |
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| Online Access: | https://doi.org/10.1088/2515-7655/ad3984 |
| _version_ | 1797211908343857152 |
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| author | Jennifer Hack Ralf F Ziesche Matilda Fransson Theo Suter Lukas Helfen Cyrille Couture Nikolay Kardjilov Alessandro Tengattini Paul Shearing Dan Brett |
| author_facet | Jennifer Hack Ralf F Ziesche Matilda Fransson Theo Suter Lukas Helfen Cyrille Couture Nikolay Kardjilov Alessandro Tengattini Paul Shearing Dan Brett |
| author_sort | Jennifer Hack |
| collection | DOAJ |
| description | Water management plays a key role in ensuring optimum polymer electrolyte fuel cell (PEFC) performance, and flow field design can influence the ability of a cell to balance maintaining hydration, whilst avoiding flooding and cell failure. This work deepens the understanding of water evolution in different PEFC flow channel designs, namely single serpentine (SS), double serpentine (DS) and parallel, using our novel high-speed neutron computed tomography method. We developed our previously-reported method by introducing continuous cell rotation, enabling 18 s per tomogram during 1 h holds at 300, 400 and 500 mA cm ^−2 . The volume of water evolved in the cathode, membrane electrode assembly and anode was quantified, and key mechanisms for water droplet formation in the different flow channel designs were elucidated. The parallel flow field design had the poorest water management, with 47% of the cathode flow channel becoming filled after 1 h at 400 mA cm ^−2 . This significant flooding blocked reactant sites and contributed to unstable cell performance and, ultimately, cell failure at higher current densities. The SS cell displayed the best water management, with only 11% of the cathode channel filled with water after 1 h at 500 mA cm ^−2 , compared with 28% of the DS cathode channel. 3D visualisation and analysis of droplet behaviour elucidated how water ‘slugs’ in the SS were removed in the gas stream, whereas three of the four parallel cathode flow channels became entirely filled with water plugs, blocking gas flow and exacerbating cell flooding. The new insights gained here are expected to extend to novel flow field designs and image-based models, with the use of operando neutron CT demonstrated as a powerful technique for both visualising and quantifying water management in operating PEFCs, as well as deepening the knowledge of droplet behaviour in different flow field types. |
| first_indexed | 2024-04-24T10:33:58Z |
| format | Article |
| id | doaj.art-e447399047e64981bcdd06c08f1de7fb |
| institution | Directory Open Access Journal |
| issn | 2515-7655 |
| language | English |
| last_indexed | 2024-04-24T10:33:58Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | JPhys Energy |
| spelling | doaj.art-e447399047e64981bcdd06c08f1de7fb2024-04-12T13:57:03ZengIOP PublishingJPhys Energy2515-76552024-01-016202502110.1088/2515-7655/ad3984Understanding water dynamics in operating fuel cells by operando neutron tomography: investigation of different flow field designsJennifer Hack0https://orcid.org/0000-0002-5529-4750Ralf F Ziesche1https://orcid.org/0000-0001-7955-6893Matilda Fransson2Theo Suter3Lukas Helfen4Cyrille Couture5Nikolay Kardjilov6Alessandro Tengattini7Paul Shearing8Dan Brett9Department of Materials Science & Engineering, University of Sheffield , Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD, United Kingdom; Electrochemical Innovation Lab, Department of Chemical Engineering, University College London , London WC1E 7JE, United Kingdom; The Faraday Institution, Quad One, Becquerel Avenue, Harwell Science and Innovation Campus, The Faraday Institute , Didcot OX11 0RA, United KingdomHelmholtz-Zentrum Berlin für Materialien und Energie (HZB) , Hahn-Meitner-Platz 1, 14109 Berlin, GermanyElectrochemical Innovation Lab, Department of Chemical Engineering, University College London , London WC1E 7JE, United Kingdom; ESRF, The European Synchrotron Radiation Facility, CS40220 , F-38000 Grenoble, FranceElectrochemical Innovation Lab, Department of Chemical Engineering, University College London , London WC1E 7JE, United KingdomInstitut Laue-Langevin , 71 Avenue des Martyrs, CS 20156, 38042 Grenoble, Cedex 9, FranceInstitut Laue-Langevin , 71 Avenue des Martyrs, CS 20156, 38042 Grenoble, Cedex 9, FranceHelmholtz-Zentrum Berlin für Materialien und Energie (HZB) , Hahn-Meitner-Platz 1, 14109 Berlin, GermanyInstitut Laue-Langevin , 71 Avenue des Martyrs, CS 20156, 38042 Grenoble, Cedex 9, FranceElectrochemical Innovation Lab, Department of Chemical Engineering, University College London , London WC1E 7JE, United Kingdom; The Faraday Institution, Quad One, Becquerel Avenue, Harwell Science and Innovation Campus, The Faraday Institute , Didcot OX11 0RA, United Kingdom; Department of Engineering Science, University of Oxford , Parks Road, Oxford, OX1 3PJ, United KingdomElectrochemical Innovation Lab, Department of Chemical Engineering, University College London , London WC1E 7JE, United KingdomWater management plays a key role in ensuring optimum polymer electrolyte fuel cell (PEFC) performance, and flow field design can influence the ability of a cell to balance maintaining hydration, whilst avoiding flooding and cell failure. This work deepens the understanding of water evolution in different PEFC flow channel designs, namely single serpentine (SS), double serpentine (DS) and parallel, using our novel high-speed neutron computed tomography method. We developed our previously-reported method by introducing continuous cell rotation, enabling 18 s per tomogram during 1 h holds at 300, 400 and 500 mA cm ^−2 . The volume of water evolved in the cathode, membrane electrode assembly and anode was quantified, and key mechanisms for water droplet formation in the different flow channel designs were elucidated. The parallel flow field design had the poorest water management, with 47% of the cathode flow channel becoming filled after 1 h at 400 mA cm ^−2 . This significant flooding blocked reactant sites and contributed to unstable cell performance and, ultimately, cell failure at higher current densities. The SS cell displayed the best water management, with only 11% of the cathode channel filled with water after 1 h at 500 mA cm ^−2 , compared with 28% of the DS cathode channel. 3D visualisation and analysis of droplet behaviour elucidated how water ‘slugs’ in the SS were removed in the gas stream, whereas three of the four parallel cathode flow channels became entirely filled with water plugs, blocking gas flow and exacerbating cell flooding. The new insights gained here are expected to extend to novel flow field designs and image-based models, with the use of operando neutron CT demonstrated as a powerful technique for both visualising and quantifying water management in operating PEFCs, as well as deepening the knowledge of droplet behaviour in different flow field types.https://doi.org/10.1088/2515-7655/ad3984polymer electrolyte fuel cellneutron tomographywater managementflow field designoperando imaging |
| spellingShingle | Jennifer Hack Ralf F Ziesche Matilda Fransson Theo Suter Lukas Helfen Cyrille Couture Nikolay Kardjilov Alessandro Tengattini Paul Shearing Dan Brett Understanding water dynamics in operating fuel cells by operando neutron tomography: investigation of different flow field designs JPhys Energy polymer electrolyte fuel cell neutron tomography water management flow field design operando imaging |
| title | Understanding water dynamics in operating fuel cells by operando neutron tomography: investigation of different flow field designs |
| title_full | Understanding water dynamics in operating fuel cells by operando neutron tomography: investigation of different flow field designs |
| title_fullStr | Understanding water dynamics in operating fuel cells by operando neutron tomography: investigation of different flow field designs |
| title_full_unstemmed | Understanding water dynamics in operating fuel cells by operando neutron tomography: investigation of different flow field designs |
| title_short | Understanding water dynamics in operating fuel cells by operando neutron tomography: investigation of different flow field designs |
| title_sort | understanding water dynamics in operating fuel cells by operando neutron tomography investigation of different flow field designs |
| topic | polymer electrolyte fuel cell neutron tomography water management flow field design operando imaging |
| url | https://doi.org/10.1088/2515-7655/ad3984 |
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