bluuebunny/crossref_metadata_2025_split huggingface dataset:
Automated Microstructural Analysis of Anodic Catalyst Layers in Proton Exchange Membrane Water Electrolyzers (PEMWEs) Using Python-Based Image Processing Framework
Authors: Batool Mariah , Ahmadi Maryam , Sanumi Oluwafemi Joseph , Larose Ravel , Horstmann Jeronimo , Klose Selina , Franzetti Irene , Yang J.V. , Yilmaz Abdurrahman , Parrish Chance , Rice Robin , Iyer Radhika , Foster Jayson , Pylypenko Svitlana , Xu Hui , Mauger Scott A , Smolinka Tom , Groos Ulf , Zamel Nada , Jankovic Jasna 
Published: August 2024

Adverse climatic conditions caused by greenhouse gas (GHG) emissions from non-renewables have led to increased focus on utilization of clean alternative fuels such as hydrogen (H2). Clean H2 can be obtained via electrochemical reaction of water splitting through proton exchange membrane water electrolyzers (PEMWEs). However, challenges to its widespread commercialization lie with the high H2 production cost, a large portion of which comes from use of expensive anodic catalyst materials. To improve anodic catalyst utilization to attain better performance at reduced cost, a thorough understanding of anodic catalyst layer microstructure is needed. In-depth characterization through scanning transmission electron microscopy with energy dispersive spectroscopy (STEM/EDS) can provide a comprehensive dataset, which can be processed further to extract structural parameters and correlate to electrochemical performance. However, extracting relevant information from these datasets can be very challenging and time-consuming.
In this study, an automatic python-based image processing framework is implemented to quantify compositional and microstructural parameters for different IrO2 based catalyst inks and their corresponding catalyst layers. The code can provide areal density of catalyst materials, pore/agglomerate size distribution, connectivity of phases, coverage of catalyst particles by ionomer, and its content percentage and distribution. Quantified parameters are then correlated with the electrochemical performance of the PEMWEs. The results provide adequate pointers to not only help capturing microstructural details of catalyst layers but also provide a basis to predict electrochemical behavior and performance of the inks and catalyst layers being studied.
(Invited) Dynamic Modeling of Liquid Alkaline Water Electrolyzers: From Laboratory Cells to Industrial-Sized Stacks
Authors: Turek Thomas , Becker Maik , Kirstein Fabian , Gäde Felix , Brauns Jörn , Lüke Lukas 
Published: August 2024

The transition of the energy system towards renewable energies creates an enormous demand for green hydrogen produced by water electrolysis [1]. Among the available processes, alkaline water electrolysis (AEL) is already well-developed and cost-effective, as it does not require expensive or critical membrane and electrode materials [2]. If the liquid alkaline electrolyte is maintained at sufficient reaction temperature (60-90 °C), efficient operation of AEL systems is possible with rapid response to fluctuating renewable power supply [3]. However, a critical phenomenon for all low-temperature water electrolysis technologies is the increased gas impurity – especially for hydrogen in oxygen – during part-load operation [4]. This decreases the process efficiency and is safety-relevant as electrolysis systems must shut down when exceeding 50% of the lower explosive limit. These impurities become dominant at low current density since gas production decreases while the contamination mechanisms (diffusion through the separator and convective transport through electrolyte cycles mixing) are almost load-independent. We have developed a comprehensive dynamic model to properly describe the performance of an AEL system, including cell voltage, electrolyte temperature, electrolyte concentration, and gas purity [5]. With this model, it is possible to describe the dynamic operation of a laboratory AEL system with high accuracy. However, if this model is employed for an industry-sized shortstack with more than 1 m2 cell size, predictions and experimental results are in lesser agreement. This is most probably because the present model assumption of perfectly mixed half-cells no longer holds in large cells with a pronounced dependency of the gas fraction over the cell height. Thus, an improved model including this height dependence must be developed.
[1] M. Wappler, D. Unguder, X. Lu, H. Ohlmeyer, H. Teschke, W. Lueke, Int. J. Hydrogen Energ. 47 (2022) 33551
[2] J. Brauns, T. Turek, Processes 8 (2020) 248
[3] J. Brauns, T. Turek, Electrochim. Acta 404 (2022) 139715
[4] P. Trinke, P. Haug, J. Brauns, B. Bensmann, R. Hanke-Rauschenbach, T. Turek, J. Electrochem. Soc. 165 (2018) F502
[5] J. Brauns, T. Turek, J. Electrochem. Soc. 170 (2023) 064510
Distribution of Relaxation Times Analysis of PEMFC through Loewner Framework: A Direct and Regularization Free Approach
Authors: Patel Bansidhar , Sorrentino Antonio , Gosea Ion Victor , Vidakovic-Koch Tanja , Antoulas Athanasios C. 
Published: August 2024

The analysis and interpretation of electrochemical impedance spectroscopy (EIS) data are often complex and challenging, despite its popularity within the field of electrochemistry. Hence, recently, we have introduced novel data-driven approach for extracting the distribution of relaxation times (DRT) from impedance data in order to improve further analysis [1, 2]. This approach is based on the Loewner framework, which is a versatile and straightforward data-driven modeling method that computes reduced-order models in a state-space representation directly from frequency response data. Thus, it allows estimation of DRT without need of regularization procedures or iterative optimization algorithms.
The effectiveness of this approach is successfully demonstrated by analysing the experimental EIS data of a polymer electrolyte membrane fuel cell (PEMFC). The results show that this method allows clear identification of the individual polarization processes based on their characteristic time constants (see Figure). Furthermore, the peaks observed in the DRT plot are correctly associated with different processes by examining spectra under various operating conditions. This is further validated by employing a physics-based model [3]. In this way, unambiguous fault identification and monitoring of the degradation state of the cell is possible and it can be the foundation for an on-board diagnostic tool.

References

[1] B. Patel, "Application of Loewner framework for data-driven modeling and diagnosis of polymer electrolyte membrane fuel cells," Master Thesis, Otto-von-Guericke-Universität Magdeburg, 2021.
[2] A. Sorrentino, B. Patel, I. V. Gosea, A. C. Antoulas, and T. Vidaković-Koch, "Determination of the distribution of relaxation times through Loewner framework: A direct and versatile approach," Journal of Power Sources, vol. 585, p. 233575, 2023/11/30/ 2023.
[3] A. Sorrentino, T. Vidakovic-Koch, R. Hanke-Rauschenbach, and K. Sundmacher, "Concentration-alternating frequency response: A new method for studying polymer electrolyte membrane fuel cell dynamics," Electrochimica Acta, vol. 243, pp. 53-64, 2017/07/20/ 2017.

Figure 1
Aspects of Reduced Performance of Proton-Exchange-Membrane Water Electrolysis Via Continuum Modeling
Authors: Dizon Arthur , Padgett Elliot , Adesso Anthony , Gawas Ramchandra , Goyal Priyamvada , Kushner Douglas I. , Wrubel Jacob A , Peng Xiong , Alia Shaun M , Mukundan Rangachary , Pivovar Bryan S. , Weber Adam Z. 
Published: August 2024

Proton-exchange-membrane water electrolysis (PEMWE) is a technology, where hydrogen is electrochemically produced from water. Efficient industrial-scale production of hydrogen via PEMWE is contingent upon developing systems that are sufficiently resilient to operate under non-ideal operating conditions. Mathematical models can provide insight into the underlying physical mechanisms and inform the development of mitigating strategies. In the current work, a cell-level non-isothermal continuum model that is based on concentrated-solution theory that accounts for multiple ionic mobile species in the membrane and ionomer, energy transport, and fluid flow through porous media, was used to investigate two challenges to PEMWE becoming a viable technology, specifically contamination and hydrogen crossover. In cationic contamination, dissolved salts in the reactant water supplant protons in the membrane and ionomer and significantly increase the applied potentials required for operation. Hydrogen crossover is a concern especially in low-current operational modes, which can arise due to PEMWE powered by variable and cyclical renewable energy sources and can result in the production of combustible gas mixtures.
For cation-contaminated cells, simulation results suggest that the uptake of the contaminant cation increased as a function of current density until local conditions in the cathode catalyst layer (cCL) allowed the contaminant desorption to occur. The model suggests that the increased cell potential is primarily due to proton activity losses in the hydrogen evolution reaction within the cCL and that ionic conductivity losses are insufficient to cause the performance losses observed experimentally. Agreement with experimental data lends the model as a possible method or predictive models for PEMWE cell recovery methods. Observations of hydrogen crossover simulations suggest several aspects of hydrogen crossover, which include that localized pressures within the catalyst layers can enhance crossover, bubble-nucleation kinetics limit the exhaust of product gases, and convective fluxes due to electroomostic drag are negligible. An improved understanding of the crossover mechanisms can inform the development of low-crossover designs and mitigation strategies.

Figure 1
(Invited) Targeted Research to Develop Next Generation PEM Water Electrolyzers
Authors: Bender Guido , Duarte Ricardo Filipe Paz Moldes , Liu Chang , Ware Sam , Young James L. , Cullen David A. , Arregui-Mena David , Zenyuk Iryna , Lang Jack Todd , Engtrakul Chaiwat , Alia Shaun M , Badgett Alex , Pivovar Bryan S. , Padgett Elliot , Wrubel Jacob A 
Published: August 2024

The utilization of low-carbon intensity hydrogen as an energy carrier promises a path to the decarbonization of sectors including electricity, heavy-duty transportation, and industry at scale. The United States Department of Energy is investing into this opportunity by heavily supporting research and development efforts for hydrogen production at scale. In recent years, the DOE has established the H2NEW consortium which consists of nine national labs and additional partners to focus on the advancement of water electrolysis. It also launched the Hydrogen Energy Earthshot in 2021, targeting the reduction of clean hydrogen production cost by 80% from $5 to $1 per 1 kg H2 produced in 1 decade. For these efforts to be successful, techno-economic analyses are used to identify the research and development areas with the greatest impact, supporting targeted studies on scalable manufacturing and materials that lower capital costs, produce hydrogen efficiently, and enable durable operation over the system lifetime.
In this presentation the challenges and trade-offs of electrolyzer operation for renewable hydrogen generation will be reviewed, and results from targeted NREL studies on components, materials and interfaces will be discussed in detail, including for example PTL morphology, PTL coatings, and PTL/catalyst layer interactions and their effect on operation with thin membrane materials, hydrogen crossover and voltage loss contributions. The presentation also touches on any advanced in-situ diagnostic development that was required for the studies, such as high pressure operation, hydrogen crossover quantification, high throughput testing, and spatial diagnostics.
3D-Printed Hierarchical Electrodes for Ampere-Level Alkaline Water Electrolysis
Authors: Chen Xiaodong , Zhou Deli , Ding Junhao , Song Xu , Li Weihong 
Published: August 2024

In the realm of water electrolysis technology, Alkaline Electrolysis Cell (ALK) hydrogen production stands as a pivotal technology, playing a critical role in the pursuit of large-scale green hydrogen production and the achievement of the "dual carbon" objective. Despite its importance, the mass transfer efficiency of commercial porous nickel electrodes currently used in ALK systems is suboptimal. These electrodes, plagued by unstable catalyst loading, typically operate at current densities between 300-500 mA/cm², seldom reaching the desired threshold of 1 A/cm². This limitation hampers the potential of ALK hydrogen production to satisfy industrial-scale hydrogen production demands.
In the quest to overcome these limitations, the concept of the Triple Periodic Minimum Surface (TPMS) structure, a cellular architecture mathematically defined and prevalent in natural biological forms such as butterfly wings and beetle shells, is introduced. The TPMS's unique geometry is adept at adapting to mechanical requirements for various applications, including structural and fluidic systems. It allows for versatile manipulation of geometric parameters like aperture size, porosity, and tortuosity, thereby substantially broadening the design possibilities for electrode structures and enhancing the efficiency of gas-liquid and electron transfer.
To harness these benefits, we propose the creation of nickel/nickel-iron electrodes using 3D printing technology. These electrodes are characterized by their cross-scale porosity, ordered structure, and adjustable TPMS design. This innovative electrode design significantly augments bubble transport efficiency and mass transfer performance, while also providing additional anchor points for catalysts, thereby enhancing the electrochemical active surface area, intrinsic activity, and stability of the composite catalyst. As a result, these electrodes achieve ampere-level current densities in ALK electrolysis cells, enhancing electrolysis efficiency and reducing energy consumption.
Our methodology involves the use of selective laser melting printing technology to fabricate multi-tier nickel/nickel-iron electrodes of varying specifications. These electrodes are then coated with MOOH catalysts using an electrochemical deposition process. Through rigorous testing and comparison of electrochemical performance parameters, we identified the optimal multi-stage nickel/nickel-iron electrode and its composite catalyst.
Electrochemical performance tests reveal that, compared to traditional commercial porous nickel electrodes, our 3D printed electrodes decrease overpotential by 14% and improve electrolytic cell efficiency by 10% at a current density of 1 A/cm². Furthermore, these electrodes exhibit minimal degradation after a 500-hour durability test. The demonstrated efficiency and durability of these 3D-printed hierarchical electrodes indicate significant potential for their application in ampere-level alkaline water electrolysis.

Figure 1
(Invited) The Latest Developments in Radiation-Grafted Anion-Exchange Membranes
Authors: Periasamy Arun Prakash , Rupesinghe Rosemary , Nash Rebecca , Willson Terrence , Bance-Souahli Rachida , Chakraborty Arup , Wang Lianqin , Whelligan Daniel K , Varcoe John R 
Published: August 2024

This invited lecture will discuss the latest developments in radiation-grafted anion-exchange membranes (RG-AEM) that are being developed for a wide range of electrochemical technologies including fuel cells, electrolysers, and reverse electrodialysis.
This presentation will discuss the following key points:
RG-AEMs can have very high conductivities and water diffusivities, however they generally have excessive water uptakes and degrees of swelling in water, as well as poor permselectivities when in contact with aqueous salt solutions.
Crosslinking can reduce swelling and improve permselectivities, but this is at the expense of conductivity.
The cationic headgroup chemistries can alter the water uptakes of the RG-AEMs, which can impact properties such as their alkali stability and permselectivity.
Subtle changes in amination can lead to RG-AEMs with very different water contents and diffusivities.
When fully hydrated, RG-AEMs in the alkali forms can have usefully high stabilities at temperatures above 60oC.
RG-AEMs can be made with multiple chemical functionalities either via the co-grafting of more than one monomer or via amination using more than one amine reagent (see scheme below).
Finally, the presentation will present some recent undergraduate project results that probe the homogeneity of grafting using a new titration technique.

Figure 1
Cyclic Olefin Copolymer-Based Reinforced Anion Exchange Membrane for Fuel Cell
Authors: Park Heemin , Nellepalli Pothanagandhi , Leonard Daniel P , Kim Yu Seung , Bae Chulsung 
Published: August 2024

Alkaline exchange membrane (AEM)-based fuel cells have emerged as a promising technology for clean energy conversion. In contrast to acidic proton exchange membrane in fuel cells, AEM fuel cells utilize an alkaline membrane AEM to facilitate the migration of hydroxide ions, offering advantages of economic earth-abundant catalysts and enhanced electrochemical reaction kinetics. However, AEMs that possess all characters of high ion conductivity, good chemical stability under high pH and temperature, robust mechanical properties, scalable synthesis, and low manufacturing costs are rare until now.
Herein, we present quaternary ammonium-functionalized cyclic olefin copolymers (COCs) as a new class of alkaline stable and low-cost AEMs. Furthermore, we developed reinforced composite AEM by impregnating the quaternary ammonium-functionalized COC into a mechanically robust matrix. The prepared COC-reinforced membrane exhibits outstanding hydroxide conductivity of 127 mS/cm at 80°C and low swelling ratio in liquid water, and excellent mechanical properties with a tensile strength > 50 MPa, and elongation at break > 248%. The H2-O2 fuel cell test exhibited a maximum peak power density of >1.2 W cm-2 at 80°C with a low high-frequency resistance (HFR) under 0.1 Ohm cm2.
Lanthanum Transition-Metal Sulfide Electrocatalysts for Overall Water Splitting
Authors: Diaz De la Cruz Germany , Singh Shantanu , Maniyanganam Ahamed Irshad , Zhao Boyang , Zayat Billal , Narayan Sri , Ravichandran Jayakanth 
Published: August 2024

Hydrogen has been identified as a sustainable energy source for the future with the potential of replacing fossil fuels due to its high gravimetric energy density and zero carbon emissions. Water electrolysis is a promising approach to the clean production of pure hydrogen, however, the benchmark catalysts of the half reactions of water electrolysis are noble-metal based, which limit the application of this technique.1 As well, the high energy barrier and sluggish kinetics of the oxygen evolution reaction limit the efficiency of the system. Therefore, it is crucial to develop robust, stable, and cost-effective materials for water electrolysis to be scalable. Lanthanum transition-metal oxide electrocatalysts have been pursued in the past for water splitting due to the high abundance of lanthanum and transition metals.2 However, these catalysts suffer from low conductivity and inherent instability towards oxygen evolution. Binary sulfides, selenides, and phosphides have also been pursued,3 but the compositional space of these materials is limited. Ternary sulfides offer a wider compositional space that allows fine-tuning for optimal performance. As a result, we have pursued the synthesis and application of the relatively unexplored ternary chalcogenides, LaMS3 (M = Ni, Co, Fe, Mn) towards water electrolysis. The efficiency of water electrolysis and stability of the materials have been tested with linear sweep voltammetry, galvanostatic measurements, and electrochemical impedance spectroscopy. We found these materials to be active towards both the hydrogen and oxygen evolution reactions, in acidic and alkaline conditions, respectively, with the catalysts exhibiting an activity trend where LaNiS3 > LaCoS3 > LaFeS3 > LaMnS3. For HER, LaNiS3 exhibits an overpotential of 340 mV at 10 mAcm-2 with a Tafel slope of 79 mV/decade. For OER, an overpotential of 373 mV at 10 mAcm-2 and a low Tafel slope of 48 mV/decade are observed. In addition, LaNiS3 proved to be highly stable with minimal change in potential over a period of 18 hours. The high activity and stability of LaNiS3 towards both half reactions of water electrolysis make it a promising candidate for a bifunctional water splitting electrocatalyst.
References

Wang, S.; Lu, A.; Zhong, C.-J. Hydrogen Production from Water Electrolysis: Role of Catalysts. Nano Convergence
2021, 8 (1), 4.

Dias, J. A.; Andrade, M. A. S.; Santos, H. L. S.; Morelli, M. R.; Mascaro, L. H. Lanthanum‐Based Perovskites for Catalytic Oxygen Evolution Reaction. ChemElectroChem
2020, 7 (15), 3173–3192.

Anantharaj, S.; Ede, S. R.; Sakthikumar, K.; Karthick, K.; Mishra, S.; Kundu, S. Recent Trends and Perspectives in Electrochemical Water Splitting with an Emphasis on Sulfide, Selenide, and Phosphide Catalysts of Fe, Co, and Ni: A Review. ACS Catal.
2016, 6 (12), 8069–8097.
Applicability of Non-PGM Bi-Functional Electrocatalyst in a Scaled-up Anion Exchange Membrane Water Electrolysis
Authors: Lee Dong-Yeol , Lee Jaeyoung , Kang Sinwoo 
Published: August 2024

While non-precious metal catalyst materials are crucial for AEMWE systems, catalyst substances possessing both adequate hydrogen molecule adsorption ability and suitable electrical conductivity and hydrophilicity are still in the developmental stage.
Ni-Mo alloy metals are known as those that have appropriate hydrogen molecule adsorption binding energy, making them excellent electrochemical catalysts for the cathode. However, they suffer from a high content of oxide, which hampers electrical conductivity, and the formation of a high oxidation state of Ni molecules, making hydrogen molecule detachment challenging.
On the other hand, Ni-Fe alloys are recognized for their excellent -OOH group adsorption ability and high electrical conductivity, and that has a low oxidation state Ni phase for high hydrogen desorption ability.
Therefore, in this study, we aimed to synthesize NiMoFe-based alloy catalysts to enhance the hydrogen evolution reaction (HER) activity of Ni-Mo group catalysts while simultaneously increasing the oxygen evolution reaction (OER) activity. Using a hydrothermal synthesis method for NiMoFe catalysts we employed a high-temperature thermal reduction process to minimize the oxide layer that has poor conductivity.
Evaluation of the catalyst activity through half-cell experiments demonstrated low overpotentials in both Overall water electrolysis reactions. Furthermore, an MEA-type experiment was conducted to evaluate the applicability of single-cell.
Furthermore, Stability tests confirmed a stable voltage.
Finally, when compared to the combination of precious metal catalysts, this exhibited superior performance. Therefore, this study suggests that non-noble catalysts could serve as a crucial stepping stone, surpassing PGM metal catalysts in alkaline media.