Abstract
Bubbles accumulation in the electrode limits anion exchange membrane water electrolyzer performance at industrial current densities (>1.0 A cm-2). Currently, conventional electrode designs prioritize the optimization of the electrochemically active surface area. However, this study reveals that bubble dynamics matters high-rate water electrolysis efficiency in anode-feeding mode in three ways:1) cover active sites at the anode; 2) hinder water diffusion through the membrane; 3) cause water shortage at the cathode. Based on this mechanism, we propose an easy-to-prepare gradient stainless steel square hole mesh electrode. It not only offers a low cost ($8-150/m2), but also improves bubble dynamics. As a result, it reduces the cell voltage by 0.14 V at a current density of 5.0 A cm-2, even with a lower electrochemically active surface area compared to the stainless steel felt electrode. And it maintains a stable operation over 400 hours. This work redefines electrode engineering paradigms, shifting focus from electrochemically active surface area-centric approaches to two-phase flow management in water electrolyzers for industrial current densities-scale hydrogen production.
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The data generated in this study are provided in the Supplementary Information/Source Data file. Source data are provided with this paper.
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Acknowledgements
This work was supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. 15308024) (received by L.A.) and by a grant from Research Centre for Carbon-Strategic Catalysis (RC-CSC), The Hong Kong Polytechnic University (CE2X) (received by L.A.).
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L.W. conceptualized the study, developed the methodology, performed the experiments, and prepared the original draft. Q.W., S.Y., and W.L. performed the investigation and validation. X.Z., M.T., and K.Z. helped polish the language. X.Y. and L.A. supervised the project and participated in the review. All authors commented on the manuscript.
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Wu, L., Wang, Q., Yuan, S. et al. Bubble dynamics matters at high-rate water electrolysis. Nat Commun (2026). https://doi.org/10.1038/s41467-026-69052-5
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DOI: https://doi.org/10.1038/s41467-026-69052-5
