bluuebunny/crossref_metadata_2025_split huggingface dataset:
Boosting Hydrogen Production: Non-Noble Metal Catalysts Optimize Electrodes in Anion Exchange Membrane Water Electrolysis
Authors: Hesse Miriam , Pineti Enado , Kaufmann Bastian , Pilaski Moritz , Radev Ivan , Manolova Mila , Sörgel Seniz , Müller Thomas Ernst , Apfel Ulf-Peter 
Published: December 2024

As the world transitions to renewable energy sources, efficient energy storage is crucial for managing power fluctuations and decarbonize crucial high temperature processes. Achieving grid balance and optimizing renewable energy capacity requires innovative solutions. One promising option is the conversion of electrical energy into hydrogen through Anion Exchange Membrane Water Electrolysis (AEM-WE).
AEM-WE combines high hydrogen production rates per electrode area and little production site footprint of Proton Exchange Membrane Water Electrolysis (PEM-WE) with cost-effectiveness of non-noble electrode materials utilized in Alkaline Water Electrolysis (A-WE). To further optimize AEM-WE, it is essential to improve hydrogen production while reducing material costs. This can be achieved through innovative approaches to electrocatalyst and electrode design. However, developing cost-effective catalysts that combine superior efficiency and robustness in aqueous environments, ideally in alkaline conditions, remains a big challenge. In this work, two electrode preparation approaches are investigated. For the anodic OER a corrosion synthesis is been developed to form highly active NiFe-layered double hydroxide (LDH) structures on nickel non-woven porous transport layers (PTL). A highly active cell can be combined with a cathodic HER catalyst, prepared by electrochemical deposition Ni-S on a stainless steel non-woven PTL.
In single cell AEM water electrolysis using 1 M KOH-solution utilizing the prepared NiFe-LDH anode and Pt/C cathode, 2.7 A/cm² at 2 V were achieved, surpassing commercially available powder catalysts like NiFe-oxide. Comparative analysis of Ni-S cathode with NiFe-LDH, integrated into a membrane electrode assembly demonstrated superior AEM-WE performance, outperforming the mentioned platinum on carbon catalysts. Electrochemical impedance spectra indicated higher charge transfer activity of Ni-S cathode compared to Pt/C. Importantly, the electrodes prepared in this study exhibited stability under accelerated electrochemical stress tests for 1000 cycles.
These approaches provide a simple, inexpensive, scalable and therefore industry-relevant fabrication method with improved active areas and excellent catalytic activity during AEM water electrolysis.

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Reduction in Fuel Cell Break-in Duration by Accelerating the Removal of Impurities in the Electrode
Authors: Kodama Kensaku , Kajiya Shuji , Yamada Haruhiko , Ohshima Ayako , Murata Hajime , Oka Noritoshi , Nomoto Shigemitsu 
Published: December 2024

For the widespread adoption of polymer electrolyte fuel cells (PEFCs), a high productivity of fuel cell stacks is required. The conditioning (also called break-in) of a PEFC is known to frequently take multiple hours and has been recognized to be a bottleneck for mass production [1]. In this study, we identify the origin of a long break-in duration in the production of Toyota Mirai stacks and demonstrate effective break-in protocols to reduce the duration.
Electrochemical measurements with a small cell and sample analyses were conducted for retrieved catalyst-coated-membranes (CCMs) after the cell assembling process in the production. Figure 1 shows the I-V curves and Tafel plots measured for the retrieved CCMs before and after a break-in, and the amounts of organic impurities in those CCMs. The results indicate that the oxygen reduction reaction activity of the cathode catalyst is suppressed by organic impurities before the break-in and that how to effectively remove those impurities is essential for reducing the break-in duration.
We developed a new break-in protocol for effectively removing impurities, where impurities desorbed from Pt surfaces in the cathode at a low potential are expected to be immediately washed away by produced water (Fig. 2(a)). As intended, the new protocol promptly brought the cell to a state where it could demonstrate its maximum performance compared to the reference protocol (Fig. 2(b)). The concept of the new protocol was applied in the break-in process for the second-generation Mirai stacks, and the break-in duration was reduced by 70% compared to the process for the first-generation Mirai stacks [2]. In the meeting, the details of the experimental results and their mechanisms are discussed.
References:
[1] F. Van Der Linden et al., J. Power Sources, 2023, 575, 233168
[2] Toyota Technical Review, 2021, vol. 66

Figure 1
Asymmetric Diaphragms and Their Influence on Gas Crossover in Alkaline Electrolysis
Authors: Kraglund Mikkel Rykær , Gellrich Florian , Xia Yifan , Rajappan Sinu Charamchirail , Aili David , Jensen Jens Oluf 
Published: December 2024

Many novel lab-scale diaphragms, as well as commercial state-of-the-art diaphragms for alkaline water electrolysis are prepared by non-solvent based phase inversion processes. On the lab-scale, the fabrication process is often asymmetric. The polymer dope is coated onto a glass plate similar to conventional film forming techniques, after which the glass substrate carrying the film is immersed into a non-solvent bath to rapidly precipitate the constituting polymer. As the film is initially only exposed to the non-solvent on the top surface, the resulting pore structure at the top surface of the film differs from that at the glass plate side.
This contribution explores a number of phase-inversion prepared diaphragms towards their pore structure, and in particular investigate how the asymmetric nature influences the electrolysis behavior at single cell level. Reference diaphragms based on polysulfone (PSU) are used as reference materials, and the investigation is extended to include diaphragms based on more novel polymers systems.
Significant differences are observed in the relative crossover of hydrogen to oxygen (HTO) as well as the oxygen to hydrogen (OTH), depending on the orientation of the diaphragm. Specifically, towards which electrode the skin layer is oriented matters. More than an order of magnitude in apparent crossover flux can be observed in some cases at otherwise identical conditions. Introducing an electrode-diaphragm gap can alleviate severe supersaturation and reduce crossover flux, whereas over compressed cells exhibit more severe degrees of crossover.
Advancing PEMFC Bipolar Plate Design: Biomimetics, Simulation, and Surrogate Modeling By Deep Neural Networks for Optimized Performance
Authors: Fedi Baptiste , Boucher Aurélien 
Published: December 2024

Proton exchange membrane fuel cells (PEMFC) represent a promising solution in the transition to cleaner and more sustainable energy sources. Their efficient and environmentally friendly operation relies in part on the performance of bipolar plates. These key components play a crucial role in the uniform distribution of reactants and the evacuation of products, directly impacting the overall efficiency of the fuel cell. By optimizing the design of bipolar plates, particularly through simulation, it is possible to significantly improve the operation of these cells.
The use of biomimetics design in bipolar plate design offers an innovative approach to maximize active species concentration, facilitate product evacuation, and reduce pressure drop. Drawing inspiration from natural structures and mechanisms, such as leaf vascular networks, optimized channel configurations can be designed to promote uniform and efficient flow of reactants and products across the plate. This approach not only enhances overall fuel cell performance but also reduces environmental footprint by optimizing resource utilization.
The use of multiphysics simulation provides a valuable tool to predict the behavior of PEMFCs based on operational parameters such as gas fluxes and operating voltage/current density. Focusing on the operating power per unit area of the bipolar plate's active surface, as well as the distribution of partial pressures in gas, water, and temperature within the cell, simulation allows for a thorough understanding of the complex interactions within the system. This enables optimization of operating conditions to enhance energy efficiency and durability of PEMFCs.
Developing a surrogate model, with Comsol Multiphysics, for bipolar plate design holds significant interest in creating an application able of real-time prediction of the impact of minor geometry modifications on local concentration distributions within the channels of the bipolar plate and gas diffusion layers (GDLs) using deep neural networks. This approach enables rapid assessment of design variations, facilitating optimization efforts and informed decision-making. By harnessing the power of deep learning, the surrogate model enhances efficiency in the design process, streamlining iterations and minimizing experimental testing requirements. This innovative approach accelerates the development of high-performance fuel cell systems.
The developed strategy combines biomimetics for designing optimized bipolar plates, multiphysics simulation to predict PEMFC behavior, and the development of a surrogate model to accelerate prototyping phase.
(Invited) Optimized Conditioning and Performance of PEM Fuel Cell Stacks
Authors: Dombrovskis Johanna , Shokhen Victor , Kylhammar Lisa , Bodén Andreas 
Published: December 2024

The fuel cell market is maturing, and the production volumes are increasing. In parallel, expectations on performance, lifetime and operational range for fuel cell stacks are growing. As fuel cell technology matures, more fuel cell stacks are used in real life applications instead of laboratory environment. These positive developments bring with them new challenges and opportunities to learn.
Several of these challenges and their impact on stack design and validation will be discussed. The focus will be on optimization of useful stack power density, fuel cell stack conditioning, enlarging the LT-PEM fuel cell operation range and on durability testing.
This talk addresses why conditioning and durability testing are closely connected and illustrates how this can impact stack platform and fuel cell development. In addition, the interactions between power density, stack integration and stack operational window are illustrated showing how each of these parameters could be optimized utilizing a current distribution plate and what trade-offs are relevant for optimized fuel cell stack and system performance.
Powercell is active in various market segments and has developed stacks and stack components for ~20 years. The optimizations and trade-offs described hinge heavily on key PEM stack requirements which can be widely different in different PEM fuel cell market sectors, as illustrated by the emerging usage of fuel cells in aviation.
Dynamic Simulation of a Hybrid PV/Awe/SOFC Stand-Alone System for Heat and Power Generation
Authors: Ham Jinyoung , Kang Sanggyu , Jang Dohyung , Shin Haeseong , SHIN Hee-SUN 
Published: December 2024

Global energy demand increased from 528 EJ in 2012 to 604 EJ in 2022, with CO2 emissions rising from 34 Gt to 36.8 Gt during the same period. According to the IEA, global energy demand is projected to reach 670 EJ by 2030. To meet this energy demand and simultaneously reduce greenhouse gas emissions, the capacity for renewable energy installations is expanding. However, renewable energy faces the issue of lacking flexibility to balance supply and demand due to its intermittency and variability. Sector coupling, which converts power to heat (P2H), gas (P2G), and liquid fuels (P2L), can overcome the flexibility challenges of renewable energy by integrating energy across sectors (power, transportation, industry, agriculture, and residential). As an energy storage medium, hydrogen serves as a key component in P2G and P2L and holds potential as a future energy carrier.
The residential sector requires both heat and electricity, yet the power supply through photovoltaics (PV) leads to an imbalance between energy demand during day and night. To alleviate this energy imbalance while flexibly meeting heat and electricity demands, a hydrogen-based 'PV-AWE-Batt-SOFC' hybrid system was proposed. Numerous previous studies have performed capacity optimization of hybrid systems with cost as the objective function. However, research on Energy Management Strategies (EMS) for stable operation of each system in conjunction with renewable energy is limited. Therefore, a stable hybrid system EMS based on the analysis of the dynamic behavior of AWE and SOFC needs to be established.
In this study, a dynamic model of the PV-AWE-Batt-SOFC hybrid system was developed using AMESim®. The AWE system consists of a stack, pump, heat exchanger, gas-liquid separator, cooling system, condenser, oxygen catalytic combustor, and dryer. The SOFC system comprises a stack, blower, heat exchanger, and after-burner. The stack was modeled with an in-house code to accurately resolve the electrochemical reactions. To establish a stable EMS for the hybrid system integrated with renewable energy, the dynamic behavior of both the AWE and SOFC systems was analyzed, and EMS scenarios were proposed. The scenarios were evaluated by comparing the state of charge of the battery and the state of charge of the hydrogen tank. Analyzed parameters in the AWE system include stack temperature/voltage, condenser temperature/hydrogen purity, oxygen catalytic combustor temperature/conversion rate, and dryer temperature/hydrogen purity. In the SOFC system, analyzed parameters are stack temperature/voltage/fuel utilization, and after-burner temperature/conversion rate.

Figure 1
Electrochemical Modeling of a Commercial Polymer Electrolyte Fuel Cell Using 3-D Micro-Computed Tomography
Authors: White Zakar , Swider-Lyons Karen , Litster Shawn 
Published: December 2024

Challenges remain with the accurate modeling and optimization of gas transport in polymer electrolyte membrane fuel cells (PEMFCs) due to the complexity of calculating transport across the relevant domains and structures in a fuel cell. Each cell comprises two bipolar plates (BPPs) compressed around a membrane electrode assembly (MEA). The bipolar plates (BPPs) are a multifunctional component having flow fields with mm-sized features designed for reactant delivery and heat and water management. The MEA comprises a 5-layer structure with microporous catalyst and gas diffusion layers (GDLs) on either side of a proton exchange membrane (PEM). Actual cell designs are further constrained by their materials, and manufacturing cost and speed.
Prior work primarily focuses on modeling the flow fields in metal BPPs as idealized geometries, neglecting the inherent curvature introduced during the stamping manufacturing process and the compression and thickness variation of the MEA layers. To create high-performance cells, it is necessary to understand the detailed interaction of the BPPs and MEAs in practical, manufactured fuel cell stacks.
In this work, a compressed short stack of unit cells from a decommissioned commercial fuel cell electric vehicle (FCEV) was resolved in three dimensions (3-D) using a micro-computed tomography instrument (micro-CT) capable of imaging large samples (up to 30 cm). Representative images from across the cell domains are shown in Figure 1. The 3-D images were subsequently segmented and meshed for computational fluid dynamics (CFD) modeling. Simulations of transport and electrochemical phenomena were performed using commercial CFD software using custom codes. Simulation results were used to assess the performance of a mesh-type cathode flow field design with secondary flows as well as the impact of compression, and stamped plate curvature. The results highlight the significant impact of the induced convective transport in the gas diffusion layers (GDLs) has on the performance of a practical fuel cell.
Acknowledgements: This material is based upon work supported by Plug Power Incorporated.
Figure Collage: Left – 3D Micro-CT Images of the BPPs and components of an MEA, Center - Meshing faces, Right – Relative Humidity Profile

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Multiscale Simulation of Internal Reforming Solid Oxide Fuel Cells to Capture Complex Reaction Phenomena
Authors: Abbasi Hamid , Babaei Masoud , Theodoropoulos Constantinos 
Published: December 2024

In our previous work, we successfully employed a multiscale modelling approach to simulate solid oxide fuel cells (SOFCs) fuelled by pure hydrogen [1]. This approach effectively captured the interplay between electrochemical and transport phenomena at various scales within the SOFC. Here, we extend this framework to investigate the complexities of internal reforming SOFCs (IR-SOFCs) fuelled by hydrocarbon fuels, such as methane. IR-SOFCs offer fuel flexibility but introduce significant modelling challenges due to the inclusion of steam methane reforming (SMR) within the anode[2]. Accurately capturing this process requires accounting for several complexities.
A multiscale modelling approach that can handle the interplay of several complex phenomena in IR-SOFCs. SMR involves a series of interconnected reactions with intricate mechanisms [3]. Unlike SOFCs working with pure hydrogen fuel, SMR reactions in IR-SOFCs may operate far from chemical equilibrium under certain operating conditions. To capture this condition, rigorous kinetic modelling across different length scales is needed. Finally, a significant challenge lies in describing the coupling between the electrochemical reactions at the anode and the chemical reactions of SMR. These phenomena are intrinsically linked, as the reforming process consumes reactants (steam and methane) that are also crucial for the electrochemical oxidation at the anode. An effective modelling framework must seamlessly integrate the transport and reaction phenomena occurring at both micro and macro scales within the SOFC electrodes. By addressing these challenges, our multiscale modelling framework aims to provide a more comprehensive understanding and optimization of IR-SOFC performance.

References:

[1] H. R. Abbasi, M. Babaei, A. Rabbani, and C. Theodoropoulos, ‘Multi-scale model of solid oxide fuel cell: enabling microscopic solvers to predict physical features over a macroscopic domain’, in Computer Aided Chemical Engineering, vol. 52, Elsevier, 2023, pp. 1039–1045.
[2] K Tseronis, I.S. Fragkopoulos, I. Bonis, and C. Theodoropoulos. Detailed Multi‐dimensional Modeling of Direct Internal Reforming Solid Oxide Fuel Cells, Fuel Cells vol. 16, no 3, pp. 294-312, 2016, https://doi.org/10.1002/fuce.201500113.

[3] E. S. Hecht et al., ‘Methane reforming kinetics within a Ni–YSZ SOFC anode support’, Appl. Catal. Gen., vol. 295, no. 1, pp. 40–51, Oct. 2005, doi: 10.1016/j.apcata.2005.08.003.
Developing Cobalt-Free, Strontium Titanium Ferrite Based Air Electrodes for Solid Oxide Cells
Authors: Hong Junsung , Reinke Jakob Michael , Barnett Scott A 
Published: December 2024

The development of stable air electrodes for Solid Oxide Cells operating at reduced temperatures (≤700°C) creates unique material design challenges. These electrodes must not only show excellent oxygen evolution and oxygen reduction reaction rates, but also be able to maintain these fast rates over the 40,000hr lifetimes envisioned for solid oxide cells. One material of significant interest for this is Sr(Ti0.3Fe0.7)O3-δ (STF), which is a mixed ionic-electronic conducting (MIEC) perovskite that has shown performance similar to that of LaxSr1-xCoyFe1-yO3-δ (LSCF) (1). Performance and stability substantially better than that of LSCF can be achieved by substitution of as little as 7% Cobalt onto the B-site of STF. (2) Reducing or eliminating the Cobalt while maintaining performance is desirable to avoid issues with its toxicity, availability, and cost. In this work, we explore Cobalt-free STF-based air electrodes; strategies explored include composites of STF and Gd0.1Ce0.9O2-δ (GDC), PrOX infiltration, and alternative B-site substitutions of STF with Ni and Cu.
One of the aims of GDC-STF composite electrodes is to improve the thermal expansion coefficient (TCE) match and adhesion with the GDC reaction barrier layer, presumably making them more robust in thermal cycling. The 50% STF – 50 % GDC composites yielded polarization resistance values similar to those of pure STF electrodes, ~ 0.2 Wcm2 at 700C in air. Over the temperature range of 200°C-850°C, the coefficient of thermal expansion (CTE) of STF-GDC closely matches the CTE of GDC (~12×10-6 K-1), representing a significant improvement compared to STF. As previously discussed by Lu et al (3), the performance of pure STF electrodes can be significantly improved by infiltration with PrOx. Here we show that infiltration of STF-GDC composites with 1, 2, or 3 PrOx infiltration steps significantly decreases initial polarization resistance, e.g., from 0.5 to < 0.2 Wcm2 at 650C, with two infiltration steps yield the lowest polarization resistance. Furthermore, long term stability tests over >2 kh show that STF-GDC electrode degradation rates can be decreased by a factor of 4 through infiltration.
Additional results for STF substituted with alternatives to Co, including Cu, Ni, and Cu-Ni, will be presented, along with the effects of exsolution induced by pre-reduction.

S.-L. Zhang, D. Cox, H. Yang, B.-K. Park, C.-X. Li, C.-J. Li and S. A. Barnett, Journal of Materials Chemistry A, 7, 21447 (2019).

S.-L. Zhang, H. Wang, M. Y. Lu, A.-P. Zhang, L. V. Mogni, Q. Liu, C.-X. Li, C.-J. Li and S. A. Barnett, Energy & Environmental Science, 11, 1870 (2018).

M. Y. Lu, R. Scipioni, B.-K. Park, T. Yang, Y. A. Chart and S. A. Barnett, Materials Today Energy, 14, 100362 (2019).