A Review of Diagnostic Tools for Evaluating Porous Transport Layers for Proton Exchange Membrane (PEM) Water Electrolysis

Aroune Ghadbane; Xiao-Zi Yuan; Alison Platt; Ali Malek; Nima Shaigan; Marius Dinu; Samaneh Shahgaldi; Khalid Fatih

doi:10.1007/s41918-025-00256-x

Electrochemical Energy Reviews ›› 2025, Vol. 8 ›› Issue (1) :23 DOI: 10.1007/s41918-025-00256-x

Review Article

review-article

A Review of Diagnostic Tools for Evaluating Porous Transport Layers for Proton Exchange Membrane (PEM) Water Electrolysis

Author information +

¹Clean Energy Innovation Research Centre, National Research Council Canada, 4250 Wesbrook Mall, V6T 1W5, Vancouver, BC, Canada

², Hydrogen Research Institute/Institute of Innovations in Ecomaterials, Ecoproducts and Ecoenergy/University of Quebec at Trois-Rivières, 3351 Boul. des Forges, C.P. 500, G9A 5H7, Trois-Rivières, QC, Canada

^a Khalid.Fatih@nrc-cnrc.gc.ca

Aroune Ghadbane

Aroune Ghadbane is a Ph.D. student in Energy and Materials at the Université du Québec à Trois-Rivières (UQTR), conducting his doctoral research at the Clean Energy Innovation (CEI) Research Centre of the National Research Council Canada in Vancouver. He holds a B.Sc. degree in General Engineering from Al Akhawayn University in Ifrane, and an M.Sc. degree in Energy Engineering from Sapienza Università di Roma, where he completed his thesis on PEM fuel cells at SINTEF and the Norwegian University of Science and Technology (NTNU) in Trondheim. His expertise lies in advanced energy-conversion systems, particularly hydrogen technologies. Aroune’s current work focuses on the development of porous transport layers for proton exchange membrane water electrolysis.

Xiao-Zi Yuan

Xiao-Zi Yuan is a Senior Research Officer at the Clean Energy Innovation (CEI) Research Centre of the National Research Council Canada (NRC). Dr. Yuan received her B.S. and M.Sc. degrees in Applied Chemistry from the Nanjing University of Technology in 1991 and 1994, respectively and her Ph.D. degree in Material Science from Shanghai Jiaotong University in 2003. Beginning in 2004, she carried out a three-year postdoctoral research program supported by Natural Sciences and Engineering Research Council (NSERC). Since 2007, Dr. Yuan has been working with NRC. Her research interests include PEM fuel cells, Li-ion batteries, Zn/Li air batteries, and other types of electrochemical devices and energy storage systems, including PEM electrolysis. Her research areas range from cell design, electrode material and structure to cell testing, diagnosis, and durability. In 2014 and 2016, Dr. Yuan was listed as Highly Cited Researcher by Thomson Reuters under the Engineering Section. Since 2019, Dr. Yuan has been classified as the top 2% researchers in the world by Stanford University and listed by Research.com among Top Scientists in the area of engineering & technology.

Alison Platt

Alison Platt is a Research Officer at the Clean Energy Innovation (CEI) Research Centre of the National Research Council Canada (NRC) in Vancouver, British Columbia. She has a BASc degree in Chemical Engineering from the University of British Columbia. Alison’s expertise includes electrochemical evaluation and characterization of proton exchange membrane (PEM) water electrolyzers, vanadium redox flow batteries (VRFBs), lithium-ion batteries, and direct liquid fuel cells.

Ali Malek

Ali Malek has been a Research Officer at the Clean Energy Innovation Centre of the National Research Council Canada in Vancouver since 2018. He obtained his Ph.D. degree in theoretical chemistry from the Institute of Physical Chemistry (IChF-PAN), Poland, in 2014, after which he completed a postdoctoral fellowship with Prof. Michael Eikerling at Simon Fraser University. His fundamental research integrates density functional theory (DFT) and molecular dynamics (MD) simulations with data-driven tools and machine-learning pipelines to accelerate the discovery of next-generation energy materials-spanning CO₂ and nitrogen reduction catalysts (CO₂RR, NRR), oxygen evolution (OER), and high-entropy alloy electrocatalysts, and porous transport layer (PTL) evaluation through automated data retrieval, NLP/LLM extraction, and graph-based predictive modeling.

Nima Shaigan

Nima Shaigan graduated from the University of Alberta with a Ph.D. degree in materials engineering in 2009. Since then, he has been working at National Research Council Canada as a Research Officer. Nima’s research focuses on identifying and resolving material-related issues for clean energy components and devices, particularly for fuel cells and water electrolysers.

Marius Dinu

Marius Dinu is a Research Officer with NRC’s Clean Energy Innovation Research Centre. Marius obtained his M.Sc. degree in Mechatronics at the Gerhard Mercator University in Germany in 2001. His professional background is Mechatronics and System Engineering, starting his engineering career with the development of fuel injection systems for diesel engines at Bosch GmbH in Stuttgart, Germany and later developing planetary gearing technology with Ikona Gear in Canada. Over the last two decades his focus is designing and building experimental electrochemical systems in the area of renewable technologies and bio-energy systems as well as developing fabrication technologies for critical components of fuel cells and electrolyzer components. In a more recent period, his focus area is proton exchange membrane (PEM) water electrolysis. Marius is responsible for the research capabilities development and implementation of PEM water electrolysis testing infrastructure, building testing stations and testing cells for PEM water electrolysis used for testing new catalyst formulations with their fabrication technologies, coatings for enhanced durability and performance as well as studying the complex interplay of catalyst coated membranes and porous transport layers. He is also overseeing the PEM water electrolysis testing activities, developing testing protocols, creating testing specification and evaluating testing data.

Samaneh Shahgaldi

Samaneh Shahgaldi is an Associate Professor at the Hydrogen Research Institute, University of Quebec and Adjunct Associate Professor at the University of Waterloo. She holds the Canada Research Chair (CRC) Tier 2 at proton exchange membrane fuel cells and electrolyzers. She is an award-winning researcher and a member of the editorial board of the International Journal of Green Energy. She was also a Senior Research Scientist at Cummins/Hydrogenics dealing with different PEM fuel cell and PEM Water electrolyzer projects. She published more than 70 articles with over 3 000 citations with an h index of 30 on the development of components for fuel cells, electrolysers and batteries. Dr. Shahgaldi has unique interdisciplinary expertise in the renewable energy field; she has made foundational contributions to research in the development of different components for fuel cells, electrolyzer and battery applications. https://shahgaldiresearchgroup.ca/. https://www.linkedin.com/in/samaneh-shahgaldi-b584089/.

Khalid Fatih

Khalid Fatih is a Principal Research Officer and Team Leader at the National Research Council of Canada (NRC). He has extensive expertise in electrocatalysis, surface electrochemistry, and electrode kinetics, with applications in fuel cells, redox fuel cells, bio-fuel cells, redox flow batteries, lithium-ion batteries, and electrolysis. One of his primary research interests is the development of materials, and the exploration of both fundamental and applied aspects of water electrolysis for cost-effective hydrogen production. Dr. Fatih leads projects aimed at developing critical materials and components for water electrolysis, as well as understanding performance degradation and failure modes. Over the past decade, Dr. Fatih has also supported Canadian and international regulators, including the Standards Council of Canada, CSA, IEC, Transport Canada, SAE G-27, and UN-Informal Working Groups (EVS-GTR and LiB TDG reclassification), in the development and adoption of battery-related codes, standards, and regulations. Since 2014, he has chaired the Canadian National Battery Committee to IEC TSC-21A.

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Abstract

As a key component of the proton exchange membrane water electrolyzer (PEMWE), the porous transport layer (PTL) not only provides mechanical support but also facilitates the supply of reactants to the electrode and the removal of produced gases and ensures efficient electrical and thermal management. Commercially available PTLs are often repurposed for other applications, such as filtration, and are not specifically tailored for PEMWE applications. Given this context, research output on PTL development has increased notably in recent years. Optimized, structured PTLs with preferred properties require applicable, relevant, and convenient diagnostic tools for PTL material development. As such, this work aims to identify and review a wide range of techniques for evaluating developed PTLs, including electrochemical techniques, custom-engineered cells, operando diagnosis, ex situ characterization, and postmortem analysis. By providing detailed information on these characterization techniques, this review aims to catalyze further research and development in the academic and industrial sectors, enhancing the understanding, development, and quality control of PTL components.

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Keywords

Porous transport layer / Diagnosis / Diagnostic tool / PEM water electrolysis / Electrolyzer / Evaluation

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Aroune Ghadbane, Xiao-Zi Yuan, Alison Platt, Ali Malek, Nima Shaigan, Marius Dinu, Samaneh Shahgaldi, Khalid Fatih. A Review of Diagnostic Tools for Evaluating Porous Transport Layers for Proton Exchange Membrane (PEM) Water Electrolysis. Electrochemical Energy Reviews, 2025, 8(1): 23 DOI:10.1007/s41918-025-00256-x

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References

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[1]	Flexibility Resources Task Force: Increasing Electric Power System Flexibility: the Role of Industrial Electrification and Green Hydrogen Production, Energy Systems Integration Group, Reston, VA. https://www.esig.energy/reports-briefs (2022). Accessed 1 Sep 2025, Accessed 10 Jan 2024

[2]	Gulli, C., Heid, B., Noffsinger, J., et al.: Global Energy Perspective 2023: Hydrogen Outlook. McKinsey & Company. https://www.mckinsey.com/industries/oil-and-gas/our-insights/global-energy-perspective-2023-hydrogen-outlook (2024). Accessed 10 Jan 2024

[3]	Carmo M, Fritz DL, Mergel Jet al. . A comprehensive review on PEM water electrolysis. Int. J. Hydrog. Energy. 2013, 38: 4901-4934.

[4]	Shirvanian P, van Berkel F. Novel components in proton exchange membrane (PEM) water electrolyzers (PEMWE): status, challenges and future needs. A mini review. Electrochem. Commun.. 2020, 114. 106704

[5]	Maier M, Smith K, Dodwell Jet al. . Mass transport in PEM water electrolysers: a review. Int. J. Hydrog. Energy. 2022, 47: 30-56.

[6]	Bernt M, Hartig-Weiß A, Tovini Met al. . Current challenges in catalyst development for PEM water electrolyzers. Chem. Ing. Tech.. 2020, 92: 31-39.

[7]	Tomić AZ, Pivac I, Barbir F. A review of testing procedures for proton exchange membrane electrolyzer degradation. J. Power. Sources. 2023, 557. 232569

[8]	Feng Q, Yuan XZ, Liu GYet al. . A review of proton exchange membrane water electrolysis on degradation mechanisms and mitigation strategies. J. Power. Sources. 2017, 366: 33-55.

[9]	Prestat M. Corrosion of structural components of proton exchange membrane water electrolyzer anodes: a review. J. Power. Sources. 2023, 556. 232469

[10]	Yuan XZ, Shaigan NM, Song CJet al. . The porous transport layer in proton exchange membrane water electrolysis: perspectives on a complex component. Sustain. Energy Fuels. 2022, 6: 1824-1853.

[11]	Ouimet RJ, Young JL, Schuler Tet al. . Measurement of resistance, porosity, and water contact angle of porous transport layers for low-temperature electrolysis technologies. Front. Energy Res.. 2022, 10. 911077

[12]	Borgardt E, Panchenko O, Hackemüller FJet al. . Mechanical characterization and durability of sintered porous transport layers for polymer electrolyte membrane electrolysis. J. Power. Sources. 2018, 374: 84-91.

[13]	Bock R, Karoliussen H, Seland Fet al. . Measuring the thermal conductivity of membrane and porous transport layer in proton and anion exchange membrane water electrolyzers for temperature distribution modeling. Int. J. Hydrog. Energy. 2020, 45: 1236-1254.

[14]	Kang ZY, Alia SM, Young JLet al. . Effects of various parameters of different porous transport layers in proton exchange membrane water electrolysis. Electrochim. Acta. 2020, 354. 136641

[15]	Pushkarev AS, Pushkareva IV, Solovyev MAet al. . On the influence of porous transport layers parameters on the performances of polymer electrolyte membrane water electrolysis cells. Electrochim. Acta. 2021, 399. 139436

[16]	Hoseini Larimi SZ, Ramiar A, Shafaghat Ret al. . The effect of geometric parameters of PTL on oxygen transport in PEM electrolysis cell. Proc. Inst. Mech. Eng. Part C J. Mech. Eng. Sci.. 2021, 235: 7484-7495.

[17]	Cruz JC, Barbosa R, Escobar Bet al. . Electrochemical and microstructural analysis of a modified gas diffusion layer for a PEM water electrolyzer. Int. J. Electrochem. Sci.. 2020, 15: 5571-5584.

[18]	Kulkarni D, Huynh A, Satjaritanun Pet al. . Elucidating effects of catalyst loadings and porous transport layer morphologies on operation of proton exchange membrane water electrolyzers. Appl. Catal. B Environ.. 2022, 308. 121213

[19]	Weber CC, Wrubel JA, Gubler Let al. . How the porous transport layer interface affects catalyst utilization and performance in polymer electrolyte water electrolysis. ACS Appl. Mater. Interfaces. 2023, 15: 34750-34763.

[20]	Peng X, Satjaritanun P, Taie Zet al. . Insights into interfacial and bulk transport phenomena affecting proton exchange membrane water electrolyzer performance at ultra-low iridium loadings. Adv. Sci.. 2021, 8. 2102950

[21]	Liu C, Shviro M, S. Gago Aet al. . Exploring the interface of skin-layered titanium fibers for electrochemical water splitting. Adv. Energy Mater.. 2021, 11. 2002926

[22]	Jia ZJ, Ning ZF, Yang GHet al. . Experimental investigation on the effect of solid-liquid interface charge transport on natural porous media flow. Transp. Porous Media. 2022, 143: 579-598.

[23]	Kim PJ, Lee JK, Lee Cet al. . Tailoring catalyst layer interface with titanium mesh porous transport layers. Electrochim. Acta. 2021, 373. 137879

[24]	Lee JK, Lau GY, Sabharwal Met al. . Titanium porous-transport layers for PEM water electrolysis prepared by tape casting. J. Power. Sources. 2023, 559. 232606

[25]	Daudt NF, Schneider AD, Arnemann ERet al. . Fabrication of NbN-coated porous titanium sheets for PEM electrolyzers. J. Mater. Eng. Perform.. 2020, 29: 5174-5183.

[26]	Schröder J, Mints VA, Bornet Aet al. . The gas diffusion electrode setup as straightforward testing device for proton exchange membrane water electrolyzer catalysts. JACS Au. 2021, 1: 247-251.

[27]	Bystron T, Vesely M, Paidar Met al. . Enhancing PEM water electrolysis efficiency by reducing the extent of Ti gas diffusion layer passivation. J. Appl. Electrochem.. 2018, 48: 713-723.

[28]	Jung GB, Yu JW, Dlamini MMet al. . Proton exchange membrane water electrolysis-effect of pretreatment before electrocoating Ti anode support. Int. J. Hydrogen Energy. 2024, 52: 22-31.

[29]	Moradizadeh L, Madhavan PV, Ozden Aet al. . Advances in protective coatings for porous transport layers in proton exchange membrane water electrolyzers: performance and durability insights. Energy Convers. Manag.. 2025, 332. 119713

[30]	Moradizadeh L, Madhavan PV, Chellehbari YMet al. . Porous transport layers with low Pt loading having Nb-Ta alloy as interlayer for proton exchange membrane water electrolyzers. Int. J. Hydrogen Energy. 2024, 94: 1114-1129.

[31]	Singh A, De BS, Singh Set al. . Exploring the engineered electroplating process for coating of gold on the inner structure of porous transport layer (PTL): performance evaluation of coating in simulated PEM electrolyzer. Int. J. Hydrog. Energy. 2025, 106: 1029-1040.

[32]	Moradizadeh L, Johar M, Mehdizadeh Chellehbari Yet al. . Optimized tantalum interlayer thickness for PTLs: enhancing PEMWE performance, stability, and reducing precious metal loading. J. Power. Sources. 2025, 647. 237360

[33]	Zhao BZ, Lee C, Lee JKet al. . Superhydrophilic porous transport layer enhances efficiency of polymer electrolyte membrane electrolyzers. Cell Rep. Phys. Sci.. 2021, 2. 100580

[34]	Kang ZY, Yu SL, Yang GQet al. . Performance improvement of proton exchange membrane electrolyzer cells by introducing in-plane transport enhancement layers. Electrochim. Acta. 2019, 316: 43-51.

[35]	Altaf H, Vorhauer N, Tsotsas Eet al. . Steady-state water drainage by oxygen in anodic porous transport layer of electrolyzers: a 2D pore network study. Processes. 2020, 8. 362

[36]	Lee JK, Bazylak A. Optimizing porous transport layer design parameters via stochastic pore network modelling: reactant transport and interfacial contact considerations. J. Electrochem. Soc.. 2020, 167. 013541

[37]	Bhaskaran S, Pandey D, Surasani VKet al. . LBM studies at pore scale for graded anodic porous transport layer (PTL) of PEM water electrolyzer. Int. J. Hydrog. Energy. 2022, 47: 31551-31565.

[38]	Salihi H, Ju H. Two-phase modeling and simulations of a polymer electrolyte membrane water electrolyzer considering key morphological and geometrical features in porous transport layers. Energies. 2023, 16: 766.

[39]	Miličić T, Altaf H, Vorhauer-Huget Net al. . Modeling and analysis of mass transport losses of proton exchange membrane water electrolyzer. Processes. 2022, 102417.

[40]	Zlobinski M, Schuler T, Büchi FNet al. . Transient and steady state two-phase flow in anodic porous transport layer of proton exchange membrane water electrolyzer. J. Electrochem. Soc.. 2020, 167. 084509

[41]	Park S, Lee W, Na Y. Performance comparison of proton exchange membrane water electrolysis cell using channel and PTL flow fields through three-dimensional two-phase flow simulation. Membranes. 2022, 12. 1260(2022)

[42]	Schmidt G, Suermann M, Bensmann Bet al. . Modeling overpotentials related to mass transport through porous transport layers of PEM water electrolysis cells. J. Electrochem. Soc.. 2020, 167. 114511

[43]	García-Salaberri PA. 1D two-phase, non-isothermal modeling of a proton exchange membrane water electrolyzer: an optimization perspective. J. Power. Sources. 2022, 521. 230915

[44]	Lopata JS, Weidner JW, Cho HSet al. . Adjusting porous media properties to enhance the gas-phase OER for PEM water electrolysis in 3D simulations. Electrochim. Acta. 2022, 424. 140625

[45]	Doan TL, Lee HE, Shah SSHet al. . A review of the porous transport layer in polymer electrolyte membrane water electrolysis. Int. J. Energy Res.. 2021, 4514207-14220.

[46]	Yasin MC, Johar M, Gupta Aet al. . A comprehensive review of the material innovations and corrosion mitigation strategies for PEMWE bipolar plates. Int. J. Hydrogen Energy. 2024, 88: 726-747.

[47]	Bessarabov, D., G. Pollet, B., Millet, P.: 2.6 PEM water electrolysis: review of current trends. In: PEM Water Electrolysis, Hydrogen and Fuel Cells Primer Series, vol. 1, pp. 30–35. Essay, Elsevier (2018)

[48]	Lettenmeier P, Kolb S, Burggraf Fet al. . Towards developing a backing layer for proton exchange membrane electrolyzers. J. Power. Sources. 2016, 311: 153-158.

[49]	Chen Q, Wang Y, Yang Fet al. . Two-dimensional multi-physics modeling of porous transport layer in polymer electrolyte membrane electrolyzer for water splitting. Int. J. Hydrog. Energy. 2020, 45: 32984-32994.

[50]	Ivasishin, O., Moxson, V.: Low-cost titanium hydride powder metallurgy. In: Titanium Powder Metallurgy: Science, Technology and Applications, pp.117–148. Essay, Elsevier (2015)

[51]	Bessarabov, D., Wang, H., Li, H., et al.: Current collectors (GDLs) and materials. In: Bessarabov, D., Wang, H., Li, H., Zhao, N. (eds.) PEM Electrolysis for Hydrogen Production: Principles and Applications, 1st edn. Essay (2015). ISBN 9781138775497

[52]	Hackemüller FJ, Borgardt E, Panchenko Oet al. . Manufacturing of large-scale titanium-based porous transport layers for polymer electrolyte membrane electrolysis by tape casting. Adv. Eng. Mater.. 2019, 21: 1801201.

[53]	Arbabi F, Kalantarian A, Abouatallah Ret al. . Feasibility study of using microfluidic platforms for visualizing bubble flows in electrolyzer gas diffusion layers. J. Power. Sources. 2014, 258142-149.

[54]	Liu C, Carmo M, Bender Get al. . Performance enhancement of PEM electrolyzers through iridium-coated titanium porous transport layers. Electrochem. Commun.. 2018, 97: 96-99.

[55]	Liu C, Wrubel JA, Padgett Eet al. . Impacts of PTL coating gaps on cell performance for PEM water electrolyzer. Appl. Energy. 2024, 356. 122274

[56]	Vincent I, Kruger A, Bessarabov D. Development of efficient membrane electrode assembly for low cost hydrogen production by anion exchange membrane electrolysis. Int. J. Hydrogen Energy. 2017, 42: 10752-10761.

[57]	Pushkareva I, Pushkarev A, Solovyev Met al. . (2020) Application of nickel foam as a porous transport layer in a anion exchange membrane water electrolyzer. Nanotechnol. Russia. 2023, 18(Suppl 2): S389-S397.

[58]	Park JE, Choi HJ, Kang SYet al. . Effect of pore structures in nickel-based porous transport layers for high-performance and durable anion-exchange membrane water electrolysis. Int. J. Energy Res.. 2022, 46: 16670-16678.

[59]	Baumann N, Cremers C, Pinkwart Ket al. . Membrane electrode assemblies for water electrolysis using WO₃-supported Ir_xRu_1-_xO₂ catalysts. Energy Technol.. 2016, 4: 212-220.

[60]	Ozden A, Shahgaldi S, Li XGet al. . A review of gas diffusion layers for proton exchange membrane fuel cells: with a focus on characteristics, characterization techniques, materials and designs. Prog. Energy Combust. Sci.. 2019, 74: 50-102.

[61]	Ozden A, Shahgaldi S, Zhao Jet al. . Degradations in porous components of a proton exchange membrane fuel cell under freeze-thaw cycles: morphology and microstructure effects. Int. J. Hydrog. Energy. 2020, 45: 3618-3631.

[62]	Kuhnert E, Hacker V, Bodner M. A review of accelerated stress tests for enhancing MEA durability in PEM water electrolysis cells. Int. J. Energy Res.. 2023, 2023. 3183108

[63]	Young JL, Kang ZY, Ganci Fet al. . PEM electrolyzer characterization with carbon-based hardware and material sets. Electrochem. Commun.. 2021, 124. 106941

[64]	Becker H, Dickinson EJF, Lu XKet al. . Assessing potential profiles in water electrolysers to minimise titanium use. Energy Environ. Sci.. 2022, 15: 2508-2518.

[65]	Wang Q, Zhou Z, Ye KQet al. . The effect of pretreatment and surface modification of porous transport layer (PTL) on the performance of proton exchange membrane water electrolyzer. Int. J. Hydrog. Energy. 2024, 53: 163-172.

[66]	Yuan S, Zhao CF, Li HYet al. . Rational electrode design for low-cost proton exchange membrane water electrolyzers. Cell Rep. Phys. Sci.. 2024, 5. 101880

[67]	Mo JK, Steen S, Kang ZYet al. . Study on corrosion migrations within catalyst-coated membranes of proton exchange membrane electrolyzer cells. Int. J. Hydrogen Energy. 2017, 42: 27343-27349.

[68]	Stiber S, Sata N, Morawietz Tet al. . A high-performance, durable and low-cost proton exchange membrane electrolyser with stainless steel components. Energy Environ. Sci.. 2022, 15: 109-122.

[69]	Lee JK. Designing microporous layers for electrolyzers using stochastic approach. JACS Au. 2024, 4: 2252-2261.

[70]	Tsotridis, G., Pilenga, A.: EU harmonised protocols for testing of low temperature water electrolysers. EUR 30752 EN, Publications Office of the European Union, Luxembourg (2021). ISBN 978-92-76-39266-8. https://doi.org/10.2760/58880, JRC122565

[71]	Schuler T, Ciccone JM, Krentscher Bet al. . Water electrolysis: Hierarchically structured porous transport layers for polymer electrolyte water electrolysis. Adv. Energy Mater.. 2020, 10: 2070009.

[72]	Rakousky C, Reimer U, Wippermann Ket al. . An analysis of degradation phenomena in polymer electrolyte membrane water electrolysis. J. Power. Sources. 2016, 326120-128.

[73]	Zhang, D., Yuan, X., Ma, Z.F.: Chatper 2 Polarization curve. In: Wang, H., Yuan, X.Z. Li, H. (eds.) PEM Fuel Cell Diagnostic Tools, pp.15–35. CRC Press (2010) ISBN: 9780429106255

[74]	Lickert T, Fischer S, Young JLet al. . Advances in benchmarking and round robin testing for PEM water electrolysis: reference protocol and hardware. Appl. Energy. 2023, 352. 121898

[75]	Moreno Soriano R, Rojas N, Nieto Eet al. . Influence of the gasket materials on the clamping pressure distribution in a PEM water electrolyzer: bolt torques and operation mode in pre-conditioning. Int. J. Hydrog. Energy. 2021, 46: 25944-25953.

[76]	Lickert T, Kiermaier ML, Bromberger Ket al. . On the influence of the anodic porous transport layer on PEM electrolysis performance at high current densities. Int. J. Hydrog. Energy. 2020, 45: 6047-6058.

[77]	Pham CV, Escalera-López D, Mayrhofer Ket al. . Essentials of high performance water electrolyzers: from catalyst layer materials to electrode engineering. Adv. Energy Mater.. 2021, 11. 2101998

[78]	Choi Y, Platzek P, Coole Jet al. . The influence of membrane thickness and catalyst loading on performance of proton exchange membrane fuel cells. J. Electrochem. Soc.. 2024, 171. 104507

[79]	Giesbrecht PK, Freund MS. Investigation of water oxidation at IrO₂ electrodes in Nafion-based membrane electrode assemblies using impedance spectroscopy and distribution of relaxation times analysis. J. Phys. Chem. C. 2022, 126: 17844-17861.

[80]	Shinagawa T, Garcia-Esparza AT, Takanabe K. Insight on Tafel slopes from a microkinetic analysis of aqueous electrocatalysis for energy conversion. Sci. Rep.. 2015, 5: 13801.

[81]	MACIAS SENSORS: The Tafel Equation: a guide to electrochemical kinetics, https://maciassensors.com/the-tafel-equation/ (2023).Accessed 17 Feb 2023

[82]	Doan TL, Lee HE, Kim Met al. . Influence of IrO₂/TiO₂ coated titanium porous transport layer on the performance of PEM water electrolysis. J. Power. Sources. 2022, 533. 231370

[83]	Yuan, X.Z., Song, C., Wang, H., et al.: Electrochemical Impedance Spectroscopy. In: PEM Fuel Cells Fundamentals and Applications. Springer, London (2009). ISBN 978-1-84882-845-2. https://www.scirp.org/reference/ReferencesPapers?ReferenceID=570350

[84]	Millet, P.: PEM water electrolysis. In: Jopek, A. G. (ed.) Hydrogen Production by Electrolysis. Essay, Wiley-VCH (2015)

[85]	Lazanas AC, Prodromidis MI. Electrochemical impedance spectroscopy-a tutorial. ACS Meas. Sci. Au. 2023, 3162-193.

[86]	Weber CC, Schuler T, De Bruycker Ret al. . On the role of porous transport layer thickness in polymer electrolyte water electrolysis. J. Power Sources Adv.. 2022, 15. 100095

[87]	Wu, J., Yuan, X. Z., Wang, H.: Chapter 4 Cyclic voltammetry. In: Wang, H., Yuan, X. Z., Li, H. (eds.) PEM Fuel Cell Diagnostic Tools, pp. 71–86. CRC Press (2010). ISBN:978-1-4398-5

[88]	Tan AD, Zhang YP, Shi XYet al. . The poisoning effects of Ti-ion from porous transport layers on the membrane electrode assembly of proton exchange membrane water electrolyzers. Chem. Eng. J.. 2023, 471. 144624

[89]	Bernt M, Schramm C, Schröter Jet al. . Effect of the IrO_x conductivity on the anode electrode/porous transport layer interfacial resistance in PEM water electrolyzers. J. Electrochem. Soc.. 2021, 168. 084513

[90]	Jiang G, Yu HM, Li YHet al. . Low-loading and highly stable membrane electrode based on an Ir@WO_xNR ordered array for PEM water electrolysis. ACS Appl. Mater. Interfaces. 2021, 13: 15073-15082.

[91]	Babic U, Tarik M, Schmidt TJet al. . Understanding the effects of material properties and operating conditions on component aging in polymer electrolyte water electrolyzers. J. Power. Sources. 2020, 451. 227778

[92]	Wagner, N.: Chapter 3 Electrochemical impedance spectroscopy. In: Wang, H., Yuan X.Z., Li, H. (eds.) PEM Fuel Cell Diagnostic Tools, pp. 37–85. CRC Press (2010). ISBN:978-1-4398-5

[93]	Rozain C, Millet P. Electrochemical characterization of polymer electrolyte membrane water electrolysis cells. Electrochim. Acta. 2014, 131: 160-167.

[94]	Bautkinova T, Utsch N, Bystron Tet al. . Introducing titanium hydride on porous transport layer for more energy efficient water electrolysis with proton exchange membrane. J. Power. Sources. 2023, 565. 232913

[95]	Brunetto C, Moschetto A, Tina G. PEM fuel cell testing by electrochemical impedance spectroscopy. Electr. Power Syst. Res.. 2009, 79: 17-26.

[96]	Fortin P, Gerhardt MR, Ulleberg Øet al. . Multi-sine EIS for early detection of PEMFC failure modes. Front. Energy Res.. 2022, 10. 855985

[97]	Warkentin H, O’Brien CP, Holowka Set al. . Early warning for the electrolyzer: Monitoring CO₂ reduction via in-line electrochemical impedance spectroscopy. Chemsuschem. 2023, 16. e202300657

[98]	Fan ZX, Yu HM, Jiang Get al. . Low precious metal loading porous transport layer coating and anode catalyst layer for proton exchange membrane water electrolysis. Int. J. Hydrogen Energy. 2022, 47: 18963-18971.

[99]	Padgett E, Bender G, Haug Aet al. . Catalyst layer resistance and utilization in PEM electrolysis. J. Electrochem. Soc.. 2023, 170. 084512

[100]

Malevich D, Jayasankar BR, Halliop Eet al. . On the determination of PEM fuel cell catalyst layer resistance from impedance measurement in H₂/N₂ cells. J. Electrochem. Soc.. 2012, 159: F888-F895.

[101]

Malkow, T., Pilenga, A., Tsotridis, G.: EU harmonised test procedure: electrochemical impedance spectroscopy for water electrolysis cells. EUR 29267 EN, Publications Office of the European Union, Luxembourg (2018). ISBN 978-92-79-88739-0. https://doi.org/10.2760/8984 , JRC107053

[102]

Garcia-Navarro JC, Schulze M, Friedrich KA. Measuring and modeling mass transport losses in proton exchange membrane water electrolyzers using electrochemical impedance spectroscopy. J. Power. Sources. 2019, 431: 189-204.

[103]

Kerner Z, Pajkossy T. On the origin of capacitance dispersion of rough electrodes. Electrochim. Acta. 2000, 46: 207-211.

[104]

Kerner Z, Pajkossy T. Impedance of rough capacitive electrodes: the role of surface disorder. J. Electroanal. Chem.. 1998, 448: 139-142.

[105]

Siracusano S, Trocino S, Briguglio Net al. . Electrochemical impedance spectroscopy as a diagnostic tool in polymer electrolyte membrane electrolysis. Materials. 2018, 11: 1368.

[106]

Polonský J, Mazúr P, Paidar Met al. . Performance of a PEM water electrolyser using a TaC-supported iridium oxide electrocatalyst. Int. J. Hydrogen Energy. 2014, 393072-3078.

[107]

Millet P, Mbemba N, Grigoriev SAet al. . Electrochemical performances of PEM water electrolysis cells and perspectives. Int. J. Hydrogen Energy. 2011, 36: 4134-4142.

[108]

EC-Lab: Application note #60: distribution of relaxation times (DRT): an introduction. Accessed Jan 2017

[109]

Boulevard S, Kadjo JJA, Thomas Aet al. . Characterization of aging effects during PEM electrolyzer operation using voltage instabilities evolution. Russ. J. Electrochem.. 2022, 58: 258-270.

[110]

Zeng Z, Ouimet R, Bonville Let al. . Degradation mechanisms in advanced meas for pem water electrolyzers fabricated by reactive spray deposition technology. J. Electrochem. Soc.. 2022, 169: 054536.

[111]

Lee JK, Lee CH, Fahy KFet al. . Accelerating bubble detachment patterned through-pores. ACS Appl. Energy Mater.. 2020, 39676-9684.

[112]

Wang WT, Yu SL, Li Ket al. . Insights into the rapid two-phase transport dynamics in different structured porous transport layers of water electrolyzers through high-speed visualization. J. Power. Sources. 2021, 516. 230641

[113]

Hartig-Weiß A, Bernt M, Siebel Aet al. . A platinum micro-reference electrode for impedance measurements in a PEM water electrolysis cell. J. Electrochem. Soc.. 2021, 168. 114511

[114]

Kang ZY, Alia SM, Carmo Met al. . In-situ and in-operando analysis of voltage losses using sense wires for proton exchange membrane water electrolyzers. J. Power. Sources. 2021, 481. 229012

[115]

Tricker AW, Lee JK, Shin JRet al. . Design and operating principles for high-performing anion exchange membrane water electrolyzers. J. Power. Sources. 2023, 567. 232967

[116]

Nagasawa K, Ishida T, Kashiwagi Het al. . Design and characterization of compact proton exchange membrane water electrolyzer for component evaluation test. Int. J. Hydrog. Energy. 2021, 46: 36619-36628.

[117]

Brightman E, Dodwell J, van Dijk Net al. . In situ characterisation of PEM water electrolysers using a novel reference electrode. Electrochem. Commun.. 2015, 52: 1-4.

[118]

Becker H, Castanheira L, Hinds G. Local measurement of current collector potential in a polymer electrolyte membrane water electrolyser. J. Power. Sources. 2020, 448. 227563

[119]

Verdin B, Fouda-Onana F, Germe Set al. . Operando current mapping on PEM water electrolysis cells. Influence of mechanical stress. Int. J. Hydrog. Energy. 2017, 42: 25848-25859.

[120]

Parra-Restrepo J, Bligny R, Dillet Jet al. . Influence of the porous transport layer properties on the mass and charge transfer in a segmented PEM electrolyzer. Int. J. Hydrog. Energy. 2020, 45: 8094-8106.

[121]

Sun SC, Xiao Y, Liang Det al. . Behaviors of a proton exchange membrane electrolyzer under water starvation. RSC Adv.. 2015, 5: 14506-14513.

[122]

Majasan JO, Cho JIS, Dedigama Iet al. . Two-phase flow behaviour and performance of polymer electrolyte membrane electrolysers: electrochemical and optical characterization. Int. J. Hydrogen Energy. 2018, 43: 15659-15672.

[123]

Mo JK, Kang ZY, Yang GQet al. . Thin liquid/gas diffusion layers for high-efficiency hydrogen production from water splitting. Appl. Energy. 2016, 177: 817-822.

[124]

Mo JK, Kang ZY, Yang GQet al. . In situ investigation on ultrafast oxygen evolution reactions of water splitting in proton exchange membrane electrolyzer cells. J. Mater. Chem. A. 2017, 5: 18469-18475.

[125]

Kang ZY, Yang GQ, Mo JKet al. . Novel thin/tunable gas diffusion electrodes with ultra-low catalyst loading for hydrogen evolution reactions in proton exchange membrane electrolyzer cells. Nano Energy. 2018, 47: 434-441.

[126]

Kang ZY, Mo JK, Yang GQet al. . Investigation of thin/well-tunable liquid/gas diffusion layers exhibiting superior multifunctional performance in low-temperature electrolytic water splitting. Energy Environ. Sci.. 2017, 10: 166-175.

[127]

Selamet OF, Pasaogullari U, Spernjak Det al. . In situ two-phase flow investigation of proton exchange membrane (PEM) electrolyzer by simultaneous optical and neutron imaging. ECS Trans.. 2011, 41: 349-362.

[128]

Selamet OF, Pasaogullari U, Spernjak Det al. . Two-phase flow in a proton exchange membrane electrolyzer visualized in situ by simultaneous neutron radiography and optical imaging. Int. J. Hydrog. Energy. 2013, 38: 5823-5835.

[129]

Hoeh MA, Arlt T, Kardjilov Net al. . In-operando neutron radiography studies of polymer electrolyte membrane water electrolyzers. ECS Trans.. 2015, 69: 1135-1140.

[130]

Seweryn J, Biesdorf J, Schmidt TJet al. . Communication: neutron radiography of the water/gas distribution in the porous layers of an operating electrolyser. J. Electrochem. Soc.. 2016, 163: F3009-F3011.

[131]

Panchenko O, Borgardt E, Zwaygardt Wet al. . In-situ two-phase flow investigation of different porous transport layer for a polymer electrolyte membrane (PEM) electrolyzer with neutron spectroscopy. J. Power. Sources. 2018, 390: 108-115.

[132]

Maier M, Dodwell J, Ziesche Ret al. . Mass transport in polymer electrolyte membrane water electrolyser liquid-gas diffusion layers: a combined neutron imaging and X-ray computed tomography study. J. Power. Sources. 2020, 455. 227968

[133]

Lee C, Lee JK, George MGet al. . Reconciling temperature-dependent factors affecting mass transport losses in polymer electrolyte membrane electrolyzers. Energy Convers. Manag.. 2020, 213. 112797

[134]

Leonard E, Shum AD, Danilovic Net al. . Interfacial analysis of a PEM electrolyzer using X-ray computed tomography. Sustainable Energy Fuels. 2020, 4: 921-931.

[135]

Mo J, Kang Z, Retterer STet al. . Discovery of true electrochemical reactions for ultrahigh catalyst mass activity in water splitting. Sci. Adv.. 2016, 2. e1600690

[136]

Kang ZY, Yang GQ, Mo JKet al. . Developing titanium micro/nano porous layers on planar thin/tunable LGDLs for high-efficiency hydrogen production. Int. J. Hydrog. Energy. 2018, 43: 14618-14628.

[137]

Lafmejani SS, Olesen AC, Kær SK. VOF modelling of gas-liquid flow in PEM water electrolysis cell micro-channels. Int. J. Hydrog. Energy. 2017, 42: 16333-16344.

[138]

Sadeghi Lafmejani S, Olesen AC, Kær SK. Analysing gas-liquid flow in PEM electrolyser micro-channels. ECS Trans.. 2016, 75: 1121-1127.

[139]

Dedigama I, Angeli P, van Dijk Net al. . Current density mapping and optical flow visualisation of a polymer electrolyte membrane water electrolyser. J. Power. Sources. 2014, 265: 97-103.

[140]

Dedigama I, Angeli P, Ayers Ket al. . In situ diagnostic techniques for characterisation of polymer electrolyte membrane water electrolysers: flow visualisation and electrochemical impedance spectroscopy. Int. J. Hydrog. Energy. 2014, 39: 4468-4482.

[141]

Hoeh MA, Arlt T, Manke Iet al. . In operando synchrotron X-ray radiography studies of polymer electrolyte membrane water electrolyzers. Electrochem. Commun.. 2015, 55: 55-59.

[142]

Leonard E, Shum AD, Normile Set al. . Operando X-ray tomography and sub-second radiography for characterizing transport in polymer electrolyte membrane electrolyzer. Electrochim. Acta. 2018, 276: 424-433.

[143]

Panchenko O, Carmo M, Rasinski Met al. . Non-destructive in-operando investigation of catalyst layer degradation for water electrolyzers using synchrotron radiography. Mater. Today Energy. 2020, 16. 100394

[144]

Panchenko U, Arlt T, Manke Iet al. . Synchrotron radiography for a proton exchange membrane (PEM) electrolyzer. Fuel Cells. 2020, 20: 300-306.

[145]

Kim PJ, Lee C, Lee JKet al. . In-plane transport in water electrolyzer porous transport layers with through pores. J. Electrochem. Soc.. 2020, 167. 124522

[146]

Bromberger K, Ghinaiya J, Lickert Tet al. . Hydraulic ex situ through-plane characterization of porous transport layers in PEM water electrolysis cells. Int. J. Hydrog. Energy. 2018, 43: 2556-2569.

[147]

Jeon DH, Kim S, Kim Met al. . Oxygen bubble transport in a porous transport layer of polymer electrolyte water electrolyzer. J. Power. Sources. 2023, 553. 232322

[148]

Hoppe E, Holtwerth S, Müller Met al. . An ex-situ investigation of the effect of clamping pressure on the membrane swelling of a polymer electrolyte water electrolyzer using X-ray tomography. J. Power Sources. 2023, 578. 233242

[149]

Stähler M, Stähler A, Scheepers Fet al. . Impact of porous transport layer compression on hydrogen permeation in PEM water electrolysis. Int. J. Hydrog. Energy. 2020, 45: 4008-4014.

[150]

Lædre S, Kongstein OE, Oedegaard Aet al. . Materials for Proton Exchange Membrane water electrolyzer bipolar plates. Int. J. Hydrog. Energy. 2017, 42: 2713-2723.

[151]

Yuan XZ, Gu E, Bredin Ret al. . Development of a 3-in-1 device to simultaneously measure properties of gas diffusion layer for the quality control of proton exchange membrane fuel cell components. J. Power. Sources. 2020, 477. 229009

[152]

Zhang HB, Hou M, Lin GQet al. . Performance of Ti-Ag-deposited titanium bipolar plates in simulated unitized regenerative fuel cell (URFC) environment. Int. J. Hydrog. Energy. 2011, 36: 5695-5701.

[153]

Kellenberger A, Vaszilcsin N, Duca Det al. . Towards replacing titanium with copper in the bipolar plates for proton exchange membrane water electrolysis. Materials. 2022, 15: 1628.

[154]

Glenn JR, Lindquist GA, Roberts GMet al. . Standard operating procedure for post-operation component disassembly and observation of benchtop water electrolyzer testing. Front. Energy Res.. 2022, 10. 908672

[155]

Rojas N, Sánchez-Molina M, Sevilla Get al. . Coated stainless steels evaluation for bipolar plates in exchange PEM water electrolysis conditions. Int. J. Hydrogen Energy. 2021, 4625929–2594325929-25943.

[156]

Rakousky C, Keeley GP, Wippermann Ket al. . The stability challenge on the pathway to high-current-density polymer electrolyte membrane water electrolyzers. Electrochim. Acta. 2018, 278: 324-331.

[157]

Shigemasa K, Wani K, Nakayama Tet al. . Effects of porous transport layer wettability on performance of proton exchange membrane water electrolyzer: mass transport overvoltage and visualization of oxygen bubble dynamics with high-speed camera. Int. J. Hydrog. Energy. 2024, 62: 601-609.

[158]

Li H, Fujigaya T, Nakajima Het al. . Optimum structural properties for an anode current collector used in a polymer electrolyte membrane water electrolyzer operated at the boiling point of water. J. Power. Sources. 2016, 332: 16-23.

[159]

Lim, A., Jeong, H.Y., Lim, Y., et al.: Amphiphilic Ti porous transport layer for highly effective PEM unitized regenerative fuel cells. Sci. Adv. 7, eabf7866(2021). https://doi.org/10.1126/sciadv.abf7866

[160]

Kang ZY, Schuler T, Chen YYet al. . Effects of interfacial contact under different operating conditions in proton exchange membrane water electrolysis. Electrochim. Acta. 2022, 429. 140942

[161]

Mo JK, Steen SM, Zhang FYet al. . Electrochemical investigation of stainless steel corrosion in a proton exchange membrane electrolyzer cell. Int. J. Hydrog. Energy. 2015, 40: 12506-12511.

[162]

Li N, Araya SS, Kær SK. Long-term contamination effect of iron ions on cell performance degradation of proton exchange membrane water electrolyser. J. Power. Sources. 2019, 434. 226755

[163]

Li N, Araya SS, Cui XTet al. . The effects of cationic impurities on the performance of proton exchange membrane water electrolyzer. J. Power. Sources. 2020, 473. 228617

[164]

Kang SY, Park JE, Jang GYet al. . Directly coated iridium nickel oxide on porous-transport layer as anode for high-performance proton-exchange membrane water electrolyzers. Adv. Mater. Interfaces. 2023, 10: 2202406.

[165]

Hayatzadeh A, Fattahi M, Rezaveisi A. Machine learning algorithms for operating parameters predictions in proton exchange membrane water electrolyzers: anode side catalyst. Int. J. Hydrog. Energy. 2024, 56302-314.

[166]

Madhavan PV, Moradizadeh L, Shahgaldi Set al. . Data-driven modelling of corrosion behaviour in coated porous transport layers for PEM water electrolyzers. Artif. Intell. Chem.. 2025, 3. 100086

[167]

Chen X, Rex A, Woelke Jet al. . Machine learning in proton exchange membrane water electrolysis: a knowledge-integrated framework. Appl. Energy. 2024, 371. 123550

Funding

Office of Energy Research and Development (OERD) and the Advanced Clean Energy (ACE) Program of the National Research Council Canada(project #NRC-23-140)

National Research Council Canada