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Lookup NU author(s): Dr Daniel NiblettORCiD, Dr Hosni Ahmed Elwan Atout, Professor Mohamed MamloukORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2025. Intensification of water electrolysers is essential to lower the cost of green hydrogen. In this study we design and test a novel alkaline water electrolyser operating without a separator diaphragm (membraneless), using instead a convective flow barrier between electrodes, saving material and energy cost. For the first time, high-speed imaging has confirmed conditions required for a clear electrode gap, with bubble separation up to high current density >4 A cm−2. This design was enabled through computational fluid dynamics simulations (OpenFOAM) developed for coupling ionic and kinetic charge transport in the electrolyte and electrodes with the insulating effect of bubble two-phase flow. A pseudo-2D, 3D-printed transparent electrolyser cells validated the fluid flow vectors using particle image velocimetry of bubbles, as well as tracking bubble transport inside the cell. The simulated current density distribution on the electrodes, along with the two-phase flow simulations showed membraneless separation of bubbles was possible and later proven in the experiments using an inactive porous barrier layer with pore diameter of <51μm. Modelling at larger scale detailed that two-phase flow of bubbles effects charge-transfer instead of ohmic transport in this system. Theoretical single-phase flow and transport models predict at 50 cm scale it can operate at low current density with low crossover (
Author(s): Niblett D, Elwan HA, Mamlouk M
Publication type: Article
Publication status: Published
Journal: Chemical Engineering Journal
Year: 2025
Volume: 519
Print publication date: 01/09/2025
Online publication date: 16/06/2025
Acceptance date: 05/05/2025
Date deposited: 30/06/2025
ISSN (print): 1385-8947
ISSN (electronic): 1873-3212
Publisher: Elsevier BV
URL: https://doi.org/10.1016/j.cej.2025.163444
DOI: 10.1016/j.cej.2025.163444
Data Access Statement: Data will be made available on request.
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