bluuebunny/crossref_metadata_2025_split huggingface dataset:
Advancements in Thin, Reinforced Proton Exchange Membranes for Water Electrolysis
Authors: Gebhardt Ryan , Wrubel Jacob A , Bartuska Samuel , Vander Woude Meghan , Wright Ben , Bender Guido , Park Andrew 
Published: September 2023

Proton exchange membrane water electrolysis (PEMWE) is emerging as one of the most promising methods to produce clean hydrogen at industrial scale. New PEMWE stack designs require high voltage efficiency and differential pressure operation without sacrificing low hydrogen in oxygen concentrations in the anode stream. Membranes used in current stack designs, such as Chemours Nafion™ N115, are thick to provide strong mechanical stability. However, employing a thinner and mechanically supported membrane can enhance both the electrochemical performance and mechanical properties. With the demand for cheaper hydrogen, these new membrane designs are needed to achieve advanced performance metrics. In this presentation, recent improvements in membrane design at Chemours will be summarized.
Novel architectures comprise a thin, reinforced composite membrane approach, utilizing a lower equivalent weight (EW) polymer that can surpass the performance of the current commercial membranes. For example, overpotential is reduced by >150 mV at 3 A/cm2 for novel membranes compared to Nafion™ N115 at 80°C. However, one concern with having a thinner film is the increase in hydrogen crossover, since the lower explosive limit (LEL) for hydrogen in oxygen is only 4 vol %. PEMWE differential pressures of up to 30 bar on the cathode side can exacerbate these hydrogen crossover challenges. To mitigate this hazard, gas recombination catalyst (GRC) additives have been implemented within the membrane where the GRC recombines hydrogen and oxygen to form water. A reduction in anodic hydrogen in oxygen content of >50x has been observed, assuring the safe operation at high differential pressures for these thin membranes. Polarization curves across different membrane constructions were analyzed as well as hydrogen crossover for various GRC designs. Comparisons will be presented demonstrating the improved performance and reduced hydrogen crossover.

Figure 1
An Open-Source Continuum Model for Anion-Exchange Membrane Water Electrolysis
Authors: Gerhardt Michael Robert , Barnett Alejandro O , Khoza Thulile , Fortin Patrick , Andrenacci Sara , Faid Alaa Y. , Karstensen Pål Emil England , Sunde Svein , Clark Simon 
Published: September 2023

Anion-exchange membrane (AEM) electrolysis has the potential to produce green hydrogen at low cost by combining the advantages of conventional alkaline electrolysis and proton-exchange membrane electrolysis. The alkaline environment in AEM electrolysis enables the use of less expensive catalysts such as nickel, whereas the use of a solid polymer electrolyte enables differential pressure operation. Recent advancements in AEM performance and lifetime have spurred interest in AEM electrolysis, but many open research areas remain, such as understanding the impacts of water transport in the membrane and salt content in the electrolyte on cell performance and degradation. Furthermore, integrating electrolyser systems into renewable energy grids necessitates dynamic operation of the electrolyser cell, which introduces additional challenges. Computational modelling of AEM electrolysis is ideally suited to tackle many of these open questions by providing insight into the transport processes and electrochemical reactions occurring in the cell under dynamic conditions.
In this work, an open-source, transient continuum modelling framework for anion-exchange membrane (AEM) electrolysis is presented and applied to study electrolyzer cell dynamic performance. The one-dimensional cell model contains coupled equations for multiphase flow in the porous transport layers, a parameterized solution property model for potassium hydroxide electrolytes, and coupled ion and water transport equations to account for water activity gradients within the AEM. The model is validated with experimental results from an AEM electrolyser cell. We find that pH gradients develop within the electrolyte due to the production and consumption of hydroxide, which can lead to voltage losses and cell degradation. The influence of these pH gradients on potential catalyst dissolution mechanisms is explored and discussed. Finally, initial studies of transient operation will be presented.
This work has been performed in the frame of the CHANNEL project. This project has received funding from the Fuel Cells and Hydrogen 2 Joint Undertaking (now Clean Hydrogen Partnership) under grant agreement No 875088. This Joint undertaking receives support from the European Union's Horizon 2020 Research and Innovation program, Hydrogen Europe and Hydrogen Europe Research. Some of this work has been performed within the MODELYS project "Electrolyzer 2030 – Cell and stack designs" financially supported by the Research Council of Norway under project number 326809.
A Novel Stack Approach to Enable High Round Trip Efficiencies in Unitized PEM Regenerative Fuel Cells
Authors: Keane Alex , Roemer Andy B. , Roberts George , Junker Toby , Capuano Christopher , Ayers Katherine E. , Wang Shiyi , Weber Adam Z. 
Published: September 2023

A Unitized Reversible Fuel Cell (URFC) system provides many benefits for energy storage by combining a fuel cell and an electrolyzer into a single stack, thus simplifying the system while decreasing weight, footprint, and material costs. URFC systems usually have low overall efficiency due to conflicting optimal operating conditions required for electrolyzer and fuel cell. This study optimized the membrane electrode assembly of the proton exchange membrane cell components to achieve 50% round trip efficiency and reliable performance under relevant duty cycles.
Several components have been studied in this project including membranes, bifunctional catalysts for oxygen reduction and evolution reactions and porous transport layers (PTL). Different strategies have been applied to increase the overall performance of the stack while maintaining a low degradation rate. In particular, we looked at reducing the thickness of membranes as well as increasing the operating temperature. A comprehensive study of bifunctional catalyst has been carried out by varying the ratio of catalysts suitable for OER and catalysts suitable for ORR. Variation of the hydrophilicity of the PTL has been done to identify the optimum amount in terms of water and gas transport in the layers for both modes of operation.
A Study on the Electrochemical Performance of MOF Based HER Catalysts for Anion Exchange Membrane Water Electrolysis
Authors: Lee Hyein , Cho EunAe 
Published: September 2023

Recently, research on anion exchange membrane water electrolysis (AEMWE) has been conducted, which has the advantage of using a non-noble transition metal catalyst to reduce cost and improve the activity and durability of the catalyst. In alkaline solutions, heterojunction catalysts are favored because the rational design of catalysts requires the ability to simultaneously dissociate water and bind hydrogen species.
In this study, N-doped carbon hollow polyhedron (NCHP) supports were synthesized using two types of metal-organic frameworks (MOFs) to enhance catalyst durability by effective active site-support interactions. Moreover, well dispersed MoC on MOFs with regularly connected metal nodes and organic ligands increased the number of active sites and improved the reaction kinetics owing to the synergistic effects between MoC and Co@NC, which enhanced the hydrogen evolution reaction (HER).
The formation mechanism of NCHP was confirmed by transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. During the half-cell test, the incorporation of MoC (MoC-Co@NC/NCHP) reduced the HER overpotential by approximately 1.8 times at 10mA/cm2 compared with that of Co@NC/NCHP. Furthermore, durability cycling was conducted from 0.1 to -0.6 V versus a reversible hydrogen electrode (RHE). The durability tests revealed that after 3000 cycles, the reduction in the HER current of MoC-Co@NC/NCHP was 1.4 and 2.7 times lower than those of Co@NC/NCHP and commercial Pt/C, respectively. This study provides two strategies to obtain highly stable NC matrix supports and highly active heterojunction catalysts.
Catalyst Application in Three-Dimensional Porous Electrodes for Alkaline Electrolysis
Authors: Russo Andrea , Jensen Jens Oluf , Kraglund Mikkel Rykær , Zhang Wenjing (Angela) , Cho EunAe 
Published: September 2023

Hydrogen is critical in the green transition, and a key system for producing green hydrogen is through alkaline electrolysis. Although the alkaline electrolyzers are mature and commercially available, vast improvements are still expected in the future 1.
Traditional and most commercially applied alkaline electrolyzer electrodes are made from massive nickel plates (or nickel-plated steel plates) with some scattered perforation. With the ongoing development of thin alkaline ion‐conducting membranes with low internal resistance, the benefit of three‐dimensional porous electrodes becomes obvious. With such electrodes, there will be no blind spots and the active catalytic area can be increased significantly. Today, most groups developing such 3D electrodes use commercial nickel foam as substrate. This limits the options to what is available in the market, moreover the purchase cost is high.
The present work aims at developing high‐performing three‐dimensional hydrogen and oxygen evolution electrodes for alkaline electrolysis. The focus will be on the application of nanostructured electrocatalysts into three‐dimensional electrode structures, similar to nickel foams.
The results obtained, so far, show homogeneous formation of nanoparticles on the surface. The analysed samples show mechanical flexibility as soon as the particles are deposited but samples become rigid after testing in a half cell setup with KOH 1 M electrolyte. Further analysis will explore changes to the microstructure. The roughness factor calculated by non-faradaic cyclic voltammetry is in the range of 75 cm2 ECSA / cm2geometric, showing higher value than the commercial Nickel foam.
Initial experiments are carried out on as-prepared samples, but more advanced catalysts are also explored based on state-of-the-art materials.

[1] IRENA - Green Hydrogen Cost Reduction: Scaling up Electrolysers to Meet the 1.5 °C Climate Goal, International Renewable Energy Agency, Abu Dhabi (2020)
Uniformly Dispersed Cobalt Catalyst on the Coffee Waste-Derived Carbon Support for Hydrogen Evolution Reaction
Authors: Sukhbaatar Bayaraa , Seo Jinmyeong , Qing Wang , Yoon Sanghwa , Yoo Bongyoung 
Published: September 2023

The research interests in transition metal catalysts on carbon support have increased last decade for expensive noble metal catalyst replacement. Because those catalysts have a large surface area, good chemical stability, and are cheap and earth-abundant. Mainly structured with Co-N-C catalysts such as Cobalt (Co) nanoparticle embedded N-doped carbon, Co single-atom catalyst on carbon, etc., are highly efficient for hydrogen evolution reaction (HER) in acidic and alkaline electrolytes.
Here, we report the uniformly dispersed cobalt catalysts (Co-SCC-N) on nitrogen (N)-doped spent coffee grounds (SCG) derived carbon support, which was further utilized as HER electrocatalyst. In the first step, SCG-derived carbon is synthesized by simple pyrolysis with ZnCl2. Then, the cobalt catalyst is prepared by adsorption of the complex Co ion with 1,10-phenanthroline on the SCG-derived carbon support, followed by pyrolysis at 800°C under a nitrogen atmosphere. Uniform and high dispersions of cobalt on the carbon substrate have been confirmed by scanning transmission electron microscopy (STEM) and energy dispersive X-ray (EDX) elemental mapping analysis. X-ray photoelectron spectroscopy (XPS) determined that the catalyst contained Co2+ ions and had nitrogen-doped. Also, X-ray diffraction (XRD) and Raman spectroscopy revealed carbon materials disorders, crystallinity, and no metal-related peaks that validated no metal clusters on the carbon. Electrochemical tests were examined by linear sweep voltammetry, Tafel, electrochemical impedance spectroscopy, and chronopotentiometry (CP) in alkaline and acidic electrolytes. Co-SCC-N exhibited excellent HER performance in an alkaline medium, which needed 0.246 V to reach 10 mA cm-2. And the CP test confirmed better stability at 10 mA cm-2 for 12 hours. The result recommends a simple synthesis method for uniformly dispersed metal catalysts on biomass-derived carbon support by a simple pyrolysis technique.
Durability and Performance of Poly(norbornene) Membranes and Ionomers in Alkaline Electrolyzers
Authors: Park Habin , Tee Hui Min , Shah Parin , Dietrich Chandler , Kohl Paul 
Published: September 2023

Ion conducting polymer electrolytes provide an enabling technology for low-temperature alkaline electrolyzers. The critical parameters of solid polymer electrolytes include ionic conductivity, ion selectivity, chemical resistance and dimensional stability in the presence of excess water. High pH operation using anion conductive polymer electrolytes has several potential advantages over acid-based polymer devices including low-cost catalysts, hydrocarbon (non-perfluorinated) polymer, and low cost cell components.
In this study, a family of hydroxide conducting, poly(norbornene) solid polymer electrolytes were synthesized and used in high-performance, durable membrane electrode assemblies for fuel cells and electrolyzers. In addition to membranes, covalently bonded, self-adherent, hydroxide conducting ionomers were used to form high-performance, durable membrane electrode assembly for water electrolysis. The self-adhesive ionomers and membranes are based on hydroxide conducting poly(norbornene) polymers. The effect of porous transport layer material and porosity was examined. High performance electrolysis with very low degradation rates was achieved using stainless steel and nickel porous transport layers and flow-channels
Mechanical and Physio-Chemical Properties of Anion Exchange Membranes and Their Implications on Industrial Scale Water Electrolysis
Authors: Klinger Andre , Schmid Guenter , Martic Nemanja , Strobl Oscar , Kress Michael , Michaels Hannes , Ignat Teodora , Maltenberger Anna 
Published: September 2023

Siemens Energy Global GmbH & Co. KG - Sustainable Energy Systems, Otto-Hahn-Ring 6, 81739 München
Membrane based water electrolysis can operate under acidic or alkaline conditions, depending on the nature of the conducting ion in the membrane. Proton conducting membranes became commercially available and sufficiently stable over the last decades, enabling to scale PEM (ProtonExchange Membrane) – electrolysis in the tens of MW range1,2 approaching GW plants.
Anion Exchange Membranes (AEM) suffered mainly from limited hydroxide stability. In recent years, AEMs with sufficient initial stability and semi-commercial availability on pilot size draw the attention of industry to invest in developing in AEM electrolysers3,4. On research scale, AEMs are mainly characterized by their ion exchange capacity, conductance, ASR, tensile strength or elongation at break5,6. For industrial application, parameters such as swelling, water uptake, permeability or solubility and viscosity of the corresponding ionomer set boundary conditions for scaling cell sizes into the square meter range and the applicability of high volume manufacturing or coating methods.
In the presentation, physio chemical properties of membranes (swelling, water uptake, IEC, conductance, stress/strain and anisotropy ) are brought in context to requirements for > 1000 cm² industrial membrane electrolysis. Investigations on ex-situ characterization of membranes are being compared to different membrane chemistries and implications for larger cell sizes are derived. First results of durability tests at 1.5 A/cm² and potential degradation mechanisms will be presented in an Ir-free electrolysis cell. Changes of morphological features of the membrane electrode assembly are
being examined by optical and scanning microscopy techniques. Membrane parameters will be correlated to the electrochemical performance (impedance, endurance) in 25 cm² cells. Relevant ex-situ measurable properties are compiled for discussion with the audience.
ACKNOWLEDGEMENT
The investigations were partly funded by the BMBF under the contract number AEMready
(FKZ:03SF0613B).
REFERENCES
1 https://www.siemens-energy.com/global/en/offerings/renewable-energy/hydrogen-solutions.html?gclid=EAIaIQobChMIsuu-wMHV wIVktZ3Ch24ngoYEAAYASAAEgJUF_D_BwE.
2 https://press.siemens-energy.com/global/en/pressrelease/new-production-facility-berlin-siemens-energy-wants-eliminate-worlds-most-potent .
3 https://www.enapter.com/applications
4 https://www.enerstack.eu/
5 D. Henkensmeier, M. Najibah, C. Harms, J. Zitka, J. o. Electrochemical Energy Conversion and Storage, 2021, Vol. 18, 024001
6 K.M. Meek, C.M. Antunes, A. Neyerlin, B.S. Pivovar, “High-Throughput Anion Exchange-Membrane Characterisation at NREL”, Electrochemical Engineering & Materials Chemistry, National Renewable Energy Laboratory, Gold, Colorado, USA
(Invited) The Design, Fabrication, and Operation of a MW-Scale Low-Temperature Electrolyzer System to Support Industry and the U.S. Dept. of Energy
Authors: Harrison Kevin William , Victor Claire , Smith Owen , Kirschbaum Asher , Sievers David 
Published: September 2023

Over the last 15 years the National Renewable Energy Laboratory (NREL) has supported industry and the U.S. Department of Energy by providing independent evaluation and performance validation of next generation electrolyzer stacks. Designated a U.S. Department of Energy user facility, the Energy Systems Integration Facility (ESIF) houses a comprehensive balance-of-plant infrastructure designed to support a wide range of drop-in electrolyzer stacks with capacities of up to 1 MW direct current (DC) electrical power. This NREL designed and fabricated infrastructure includes four individual power supplies (250V, 4000A Total), high-quality and high-flow deionized water (DIW) supply (up to 300 GPM), water polishing and particulate filters to achieve better than 10MΩ-cm resistive water, heat rejection via a plate heat exchanger and facility chilled water, gas/liquid phase separation of hydrogen and oxygen from water, and a hydrogen dryer bed to reduce water vapor content to less than 5 parts per million by volume to enable compression, storage and use in a wide variety of applications including light- and heavy-duty fueling, onsite fuel cell research and development (R&D), and biological and thermochemical processes requiring hydrogen. Safety, monitoring, data archiving, and control of the electrolyzer and balance of system are achieved using custom controls programmed specifically to achieve a safe and flexible architecture.
Robust and redundant safety systems ensure safe and reliable long-duration, unattended operation of the electrolyzer with downstream compression equipment and systems consuming the product gas directly from the stack. Working with a small business, NREL is working to develop a low-cost individual cell voltage (iCVM) monitoring system capable of monitoring 100’s of cell voltages in the 2 – 3V range at a rate of 1 sample per second. The presentation will highlight critical safety considerations including reliable hydrogen-in-oxygen monitoring, lessons learned, and performance date taken over last 15 years of designing, building, and operating lab- and megawatt-scale low-temperature water electrolyzer systems.
(Invited) Electrolyser Manufacturing Scale-up Versus Design Development for Meeting Green H2 Targets
Authors: Fahy Kieran , Sinanan Anson , Joos Nathan 
Published: September 2023

Cummins-Hydrogenics pioneered our MW-scale PEM electrolysis cell stack architecture in 2012 and has built and operated multiple sites since, including the 20 MW Bécancour facility for Air Liquide from 2020. Lessons learned from these projects provide a springboard for large-scale manufacturing and deployment of PEM electrolysers worldwide and Cummins has announced GW-scale manufacturing deployment in Europe, N America and Asia. This is required to meet the growing global demand for PEM electrolysers, which derives from the targets and subsidies for green hydrogen production announced by many governments.
Concurrent to this manufacturing scale-up, significant work on cost reduction and technology advancement is ongoing resulting in anticipated cost decreases from catalyst loading (Ir<150g/MW), efficiency improvements (<46 kWh/kg) and higher current density, all of which need to be achieved for commercial viability. Driving down the Ir-loading of PEM electrolysers while increasing current densities will remain the primary driver of CapEx reductions in the short to medium term but the deployment of large-scale manufacturing also allows for significant economies of scale. Recycling and regeneration of used components will also become a larger issue and new processes need to be implemented for each stack component.
Moving from a project-based design methodology to design for volume manufacturing, all while maintaining the fast pace of technology development, makes for significant challenges and can lead to processing waste and inefficiencies. Rigorous testing and validation protocols are needed across the industry in order to successfully scale-up while implementing technology improvements necessary to meet TCO targets. This talk will focus on the juxtaposition of these challenges and ways to mitigate future risks.
Green Hydrogen via PEM Electrolysis – Avoiding Iridium Supply Limitations
Authors: Clapp Mark , Zalitis Christopher Mark , Ryan Margery 
Published: September 2023

Proton exchange membrane water electrolysis (PEMWE) is projected to become a key technology to enable the decarbonisation of ‘hard to abate’ sectors of the economy. However, the technology’s reliance on iridium, one of the scarcest elements on Earth, as an oxygen evolution reaction catalyst, has led to uncertainty over whether a large-scale PEMWE industry can be realised. This work investigates the future iridium demand of the global PEMWE sector and examines how different catalyst strategies can improve iridium utilisation in the anode catalyst. Iridium utilisation targets necessary to avoid a situation where the PEMWE sector becomes limited by iridium supply are reviewed. Modelling the iridium demand of the PEMWE sector showed that iridium utilisation needs to improve by an order of magnitude by 2050 to avoid iridium supply limiting the capacity expansion. Furthermore, closed-loop recycling of iridium would increase the installed capacity in 2050 by 170%. If these two conditions are met, global PEMWE capacity could reach 1.3 TW by 2050 using only 20% of annual global primary iridium supply, which we consider to be realistic given future demand projections. Different types of iridium-based anode catalysts are compared in terms of iridium utilisation using catalyst coated membrane (CCM) testing data from the literature. The need to place greater research focus on catalyst stability and the ability to make homogeneous catalyst layers at low iridium loadings is established. As a main result, it is found that a terrawatt-scale PEMWE industry can avoid being constrained by iridium supply as long as technological development of a similar level to that seen in PEM fuel cells and high iridium recycling rates are realised.
Reference: Perspectives on Current and Future Iridium Demand and Iridium Oxide Catalysts for PEM Water Electrolysis, submitted to Catalyst Today ‘Catalysis for the Future’ special edition.

Figure 1