X-ray measurements of gas distribution in a zero gap alkaline water electrolyzer

On Yu Dung; Stephan Boden; A.W. Vreman; Niels G. Deen; Markus Schubert; Yali Tang

doi:10.1016/j.ijhydene.2025.01.110

X-ray measurements of gas distribution in a zero gap alkaline water electrolyzer

On Yu Dung
, Stephan Boden
, A.W. Vreman (Corresponding author)
, Niels G. Deen
, Markus Schubert
, Yali Tang

Research output: Contribution to journal › Article › Academic › peer-review

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Abstract

X-ray radioscopy was used to measure the 2D projected dynamic void fraction in a zero/narrow gap alkaline water electrolyzer at a spatial resolution of 15μm, for narrow gap sizes up to 300μm and current densities up to 0.54 A/cm². As expected, the void fraction in the bulk was found to increase along the cell height and with increasing current density. The void fraction measured in the gap region (the space between the diaphragm and the electrode and its holes) was always larger than in the bulk. It hardly depended on the gap size at current densities below 0.3 A/cm². The lowest cell potential was measured for zero gap. No evidence of isolating gas pockets/films in the gaps was found. Liquid crossover and oxygen void fraction exceeding the hydrogen void fraction occurred for porous plate electrodes, but these phenomena were suppressed for perforated foil electrodes.

Original language	English
Pages (from-to)	835-844
Number of pages	10
Journal	International Journal of Hydrogen Energy
Volume	105
DOIs	https://doi.org/10.1016/j.ijhydene.2025.01.110
Publication status	Published - 4 Mar 2025

Bibliographical note

Publisher Copyright:
© 2025 The Authors

Funding

This project is funded by NWO (ECCM KICKstart DE-NL program, KICH1.ED04.20.014) and co-funded by Nobian. Hans Lammers (Nobian) is acknowledged for suggesting foil-PMMA electrodes. Jan Timmers and Bart van Sassen are acknowledged for the design of the prototype and the improvement to the final design of the electrolyzer, respectively. We acknowledge the technician Hans van Griensven from the Power and Flow group for giving advices on the design, Henri Vliegen and Thijs van Mol for the mechanical support, and the Eindhoven Prototype Center (EPC) (Gerrit Fimerius, Luciano Oorthuizen, and Bram Kerkhoff) for building the components of the setup. We also acknowledge the technicians Nico Bley, Andr\u00E9 Flaisz, Jan Sch\u00E4fer, Ronny Berger, and Uwe Sprewitz at HZDR for the technical support of the X-ray experiments at HZDR. Frank Barthel and Dominic Windisch are also thanked for their patience with us since we occupied and blocked the X-ray laboratory almost all the time. We thank Prof. Uwe Hampel for approval and the facilitation of this project at HZDR.

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 7 Affordable and Clean Energy

Keywords

Alkaline water electrolysis
Bubbles
Gas volume fraction
X-ray
Zero gap

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10.1016/j.ijhydene.2025.01.110

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Cite this

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title = "X-ray measurements of gas distribution in a zero gap alkaline water electrolyzer",

abstract = "X-ray radioscopy was used to measure the 2D projected dynamic void fraction in a zero/narrow gap alkaline water electrolyzer at a spatial resolution of 15μm, for narrow gap sizes up to 300μm and current densities up to 0.54 A/cm2. As expected, the void fraction in the bulk was found to increase along the cell height and with increasing current density. The void fraction measured in the gap region (the space between the diaphragm and the electrode and its holes) was always larger than in the bulk. It hardly depended on the gap size at current densities below 0.3 A/cm2. The lowest cell potential was measured for zero gap. No evidence of isolating gas pockets/films in the gaps was found. Liquid crossover and oxygen void fraction exceeding the hydrogen void fraction occurred for porous plate electrodes, but these phenomena were suppressed for perforated foil electrodes.",

keywords = "Alkaline water electrolysis, Bubbles, Gas volume fraction, X-ray, Zero gap",

author = "Dung, \{On Yu\} and Stephan Boden and A.W. Vreman and Deen, \{Niels G.\} and Markus Schubert and Yali Tang",

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doi = "10.1016/j.ijhydene.2025.01.110",

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T1 - X-ray measurements of gas distribution in a zero gap alkaline water electrolyzer

AU - Dung, On Yu

AU - Boden, Stephan

AU - Vreman, A.W.

AU - Deen, Niels G.

AU - Schubert, Markus

AU - Tang, Yali

PY - 2025/3/4

Y1 - 2025/3/4

N2 - X-ray radioscopy was used to measure the 2D projected dynamic void fraction in a zero/narrow gap alkaline water electrolyzer at a spatial resolution of 15μm, for narrow gap sizes up to 300μm and current densities up to 0.54 A/cm2. As expected, the void fraction in the bulk was found to increase along the cell height and with increasing current density. The void fraction measured in the gap region (the space between the diaphragm and the electrode and its holes) was always larger than in the bulk. It hardly depended on the gap size at current densities below 0.3 A/cm2. The lowest cell potential was measured for zero gap. No evidence of isolating gas pockets/films in the gaps was found. Liquid crossover and oxygen void fraction exceeding the hydrogen void fraction occurred for porous plate electrodes, but these phenomena were suppressed for perforated foil electrodes.

AB - X-ray radioscopy was used to measure the 2D projected dynamic void fraction in a zero/narrow gap alkaline water electrolyzer at a spatial resolution of 15μm, for narrow gap sizes up to 300μm and current densities up to 0.54 A/cm2. As expected, the void fraction in the bulk was found to increase along the cell height and with increasing current density. The void fraction measured in the gap region (the space between the diaphragm and the electrode and its holes) was always larger than in the bulk. It hardly depended on the gap size at current densities below 0.3 A/cm2. The lowest cell potential was measured for zero gap. No evidence of isolating gas pockets/films in the gaps was found. Liquid crossover and oxygen void fraction exceeding the hydrogen void fraction occurred for porous plate electrodes, but these phenomena were suppressed for perforated foil electrodes.

KW - Alkaline water electrolysis

KW - Bubbles

KW - Gas volume fraction

KW - X-ray

KW - Zero gap

UR - https://www.scopus.com/pages/publications/85216113322

U2 - 10.1016/j.ijhydene.2025.01.110

DO - 10.1016/j.ijhydene.2025.01.110

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SN - 0360-3199

VL - 105

SP - 835

EP - 844

JO - International Journal of Hydrogen Energy

JF - International Journal of Hydrogen Energy

ER -

X-ray measurements of gas distribution in a zero gap alkaline water electrolyzer

Abstract

Bibliographical note

Funding

UN SDGs

Keywords

Access to Document

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