Electrolyser 2030 - Cell and stack designs (MODELYS)

• Norby, Truls (2024). Protonic conduction on oxide surfaces - role and applications in electrochemical energy conversion. Progress in Energy. 6, s. 043002–043002. doi: 10.1088/2516-1083/ad6c9f. Fulltekst i vitenarkiv Vis sammendrag

  Protonic conduction on surfaces of oxides has over the last two decades drawn attention for its possible utilisation in electrolytes for energy conversion at low temperatures and for its roles in enhancement of catalytic activity. This has led to deeper investigation and increased understanding of the phenomenon and development of quantifiable models. Along with this has emerged apparent demonstrations of use of such conduction in low-drain fuel cells as well as acknowledgement of the role of surface protonic conduction in electrodes for solid-state electrochemical and photoelectrochemical cells. Here is provided a brief review and elaboration of the fundamentals of the interaction of water and hydrogen with oxide surfaces, and models for the resulting protonic conduction in chemisorbed and physisorbed layers. We finally discuss aspects of surface protonic conduction in a range of applications, including sensors, catalysis, and electrochemical and photoelectrochemical energy conversion.

• Gerhardt, Michael; Østenstad, Jenny S.; Barnett, Alejandro Ricardo Oyarce & Thomassen, Magnus (2023). Modeling Contact Resistance and Water Transport within a Cathode Liquid-Fed Proton Exchange Membrane Electrolyzer. Journal of the Electrochemical Society. ISSN 0013-4651. 170(12). doi: 10.1149/1945-7111/ad129d. Fulltekst i vitenarkiv Vis sammendrag

  Conventional proton-exchange membrane (PEM) water electrolyzers use thicker membranes (>175 μm) than their PEM fuel cell counterparts (<25 μm), which reduces hydrogen crossover but also reduces electrolyzer efficiency due to the increased resistance. Reduction of hydrogen crossover is critical in conventional systems to avoid buildup of hydrogen in the anode above the lower flammability limit. New concepts for operating PEM water electrolyzers are emerging, such as the patented concept involving liquid water supply at the cathode while operating the anode with air, which reduces the safety concern related to hydrogen crossover using thin membranes. Experimental work has demonstrated the viability of this approach, but open questions remain regarding the interplay between water transport, water consumption, and cell performance, as well as identifying the components and material properties that enable high performance. In this work, a physics-based computational model of a cathode-fed PEM water electrolyzer was developed. The model highlights the importance of limiting contact resistance and explores the effect of cell compression on non-uniformity of current distributions. Sensitivity studies found that membranes up to 50 μm thick can be used without significant water transport limitations.

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• Strandbakke, Ragnar; Vøllestad, Einar; Singh, Kalpana & Norby, Truls (2025). Influence of bias on electrode reactions for Proton Ceramic Cells. Vis sammendrag

  In this work, we investigate electrode overpotential of positrodes under anodic and cathodic operation. We study how the impedance of several state-of-the-art positrode materials is affected by applied bias and propose a model for decoupling the kinetic and mass transfer contributions to the total electrode polarisation. Furthermore, we investigate how partial electronic conductivity – affected by applied bias – disguise the true electrode impedance. The model is tested for two different electrolytes – BaZr0.7Ce0.2Y0.1O3 (BZCY721) and BaZr0.4Ce0.4Y0.2O3 (BZCY442) – displaying different ionic- to electronic transference numbers and revealing the true influence of p-type conductivity on measured impedance under anodic and cathodic bias. The results enable decoupling of three main charge carriers – electron holes, protons and oxygen vacancies – and show how the partial currents are affected by temperature, pO2 and pH2O. Moreover, the kinetic part of the overpotential is revealed as more influential than previously interpreted from the small low-capacitance charge transfer reaction at the electrolyte-electrode interface as seen by EIS at OCV. The results are obtained by applying voltage over BZCY button-cells with three-electrode configuration in symmetrical atmosphere, and stepwise modelling of electrolyte and electrode impedances for three charge carriers. We propose a correction for the effect of the counter electrode overpotential on p-type conductivity, enabling full modelling of electrode impedance under bias

• Norby, Truls (2024). Charge and mass transfer in positrodes of proton ceramic electrochemical cells. Fulltekst i vitenarkiv
• Sun, Xinwei & Norby, Truls (2024). Charge and mass transfer polarisation of BGLC37 positrodes for proton ceramic electrochemical cells. Fulltekst i vitenarkiv
• Norby, Truls (2024). Mechanisms and polarisation of electrodes for proton ceramic electrochemical cells (PCECs). Fulltekst i vitenarkiv
• Norby, Truls (2024). Mechanisms and Polarisation of Electrodes for Proton Ceramic Electrochemical Cells. Fulltekst i vitenarkiv
• Norby, Truls; Wu, Mengxin; Ewerhardt, Patrick & Sun, Xinwei (2024). Charge and Mass Transfer Polarisation of Electrodes for Proton Ceramic Electrochemical Cells. Fulltekst i vitenarkiv
• Gerhardt, Michael; Barnett, Alejandro Ricardo Oyarce; Khoza, Thulile; Fortin, Patrick Joshua; Andrenacci, Sara & Faid, Alaa Yahia Abulgheit A. [Vis alle 9 forfattere av denne artikkelen] (2023). An Open-Source Continuum Model for Anion-Exchange Membrane Water Electrolysis. Fulltekst i vitenarkiv Vis sammendrag

  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.

• Norby, Truls (2023). Transport in electrolytes and electrodes of proton ceramic electrochemical cells (PCECs). Fulltekst i vitenarkiv
• Norby, Truls (2023). Proton Conducting Ceramics - Science and Applications. Fulltekst i vitenarkiv
• Norby, Truls (2023). Thermodynamics and polarisation of electrodes for proton ceramic electrochemical cells. Fulltekst i vitenarkiv
• Norby, Truls (2023). Model and parameterisation of positrodes for proton ceramic electrochemical cells. Fulltekst i vitenarkiv

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