bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Deformable Electronics Based on Strain-Engineered Van Der Waals Materials
Authors: Nam SungWoo
Published: August 2024

Materials exhibit drastically different physical and chemical properties as their dimensionality varies. Atomically-thin van der Waals (vdW) materials possess unique mechanical, electrical, optical, and thermal characteristics, originated from quantum confined low-dimensionality and a lack of dangling bond. In particular, strong in-plane covalent bonding and weak interlayer vdW interaction of two-dimensional (2D) vdW materials enable exceptional combination of mechanical properties, such as high Young’s modulus, high in-plane strength, and ultralow bending stiffness at a level of cell membrane. Moreover, mechanical strain can induce modulation of electronic and phononic band structures of 2D vdW materials more effectively due to mechanical resilience and high surface-to-volume ratio. For these reasons, deformation engineering has garnered substantial interest in mechanics, materials and electronics communities as a new tuning knob for emerging phenomena and functionalities of 2D vdW materials. In this talk, I will discuss deformation engineering of 2D vdW materials – (1) active and dynamic deformation strategies, including in-plane interfacial slippage and out-of-plane structural deformation, (2) deformation strain induced phenomena, and (3) emerging device concepts based on deformation engineering of 2D vdW materials.
Developing Field Effect Transistor Sensors Based on DNA Probes to Detect Staphylococcus Lugdunensis Bacteria
Authors: Thokchom Rohan , Su Yi-De , Tseng Huan-Wei , Kalaimani Vishal Mani , Lin Chia Kai , Zeng Guan-Cheng , Wang Yu-Lin
Published: August 2024

The goal of this research is to work with an Electrical Double Layer (EDL)-gated Field Effect Transistor (FET) to detect the bacteria Staphylococcus lugdunensis, which can cause a variety of illnesses, including infections of the skin and soft tissues. In rare cases, Staphylococcus lugdunensis can be successfully identified using the combination of a positive catalase test, a negative tube coagulase test, a positive PYR test, and a positive ornithine decarboxylase test. We are employing an Electrical Double

Layer (EDL)-gated Field Effect Transistor (FET) to speed up the procedure because this test is time consuming and requires a highly competent individual to perform. An ssDNA probe was developed, and effectively immobilized on a gold surface electrode sensor with a square surface, and due to hybridization with the cDNA at different concentrations, electrical signals were generated in the form of current.

Our sensor was fabricated using photolithography where the gold electrode surface having 500 μm x 500 μm gate sensing area consisting of each individually addressable sensor arranged in a 1 x 8 array which is the extent gate was expose for immobilization purpose. The sensor was then subjected

to O2 plasma & HCl solution for surface cleaning and fluorescence image of baregold were taken Figure1(b).

The Single-Stranded DNA comprising of fluorescent dye (FAM) at 3’ and thiol modifier at 5’ was drop-casted on the gold surface and was incubated for 24 hours at 24°C. After, it went through a washing process in order to remove the unbound ssDNA and fluorescence images were taken. We observed that intensity was higher than that of baregold which indicates that our probe has successfully immobilized on the gold surface Figure 1(b).

Figure 1(a) represents the device that we designed. The system works with N-Channel Enhancement-Mode DMOS FET (VN10LP) in which a continuous drain voltage (3.5 V) was applied and the drain current which is the signal, were measured at two distinct gate bias voltage (2V and 3V). cDNA having quencher (BHQ1) at 5’ was diluted in different concentration namely 1fM, 10fM, 100fM and 1000fM. These cDNA with different concentrations were drop-casted on our sensor with Tris-EDTA (TE) buffer as the baseline and starting with lower concentration to higher concentration every after 12 seconds periodically where we record the change in signal as shown in Figure 1(c).

After the electrical measurement, fluorescence image was taken and we can observe that it quenched which indicates that the cDNA and the immobilized ssDNA has successfully hybridized which give the signal change.

Figure 1: (a) Surface Immobilization Principal Display in Extended Gate EDL BioFETs. (b)

Fluorescence value comparison. (c) Plot showing the change in drain current over time for aptamer

sensors exposed to various cDNA concentrations.

Figure 1
The Self-Powered Thermoelectric System Driving an Electric Field for Raman-Spectrum Glucose Quantitative Analysis
Authors: Shih Jing-Siang , Liu Kuei-Lin , Lin Zong-Hong
Published: August 2024

For a long time, blood glucose monitoring has been a challenging issue in the field of medicine. Although it is possible to visit a hospital for regular blood tests to track blood sugar concentration, the physiological reactions triggered by blood collection might lead to feeling weak, dizzy, or even vomiting. Therefore, especially for diabetic patients, they need to frequently monitor their blood sugar concentration in their daily lives to ensure their health. Currently, the primary methods for blood glucose testing still rely on invasive techniques, such as using fingertip glucose meters and other methods which require skin puncture to obtain blood samples. Although these methods provide a quick assessment of current blood glucose concentration, they come with the pain and discomfort of blood collection process and the potential risk of infection. As a result, in recent years, many researchers have been dedicated to developing non-invasive blood glucose monitoring methods. However, accurately measuring glucose concentration inside the human body remains a challenging task. One of the primary issues is the presence of strong noise and background noise. To avoid this challenge, we have developed an innovative detection platform that is combines surface-enhanced Raman spectroscopy (SERS) and external electric field sensing technology. With the electromagnetic effect, we add external electric field in our platform to excite more the surface plasmon resonance. By using this method, we can achieve signal amplification to detect lower concentrations of glucose. Now, we can detect down to 0.001mM of glucose. We also exhibit self-powered electric field system, using the flexible themoelctric device to combine our platform. By the property of self-powered, we success to create a self-powered electric field system. We focus on driving themoelectric through the temperature different between body temperature and environment. The approach is aimed at generating power from the human body, providing a self-powered thermoelectric system for Raman-spectrum glucose sensors. This innovative approach holds promise for advancing non-invasive blood glucose monitoring and benefiting a larger population of diabetes patients in the future.
Exploring Neuromorphic Computing with Double-Gate Floating Device Based on Van Der Waals Heterostructures
Authors: Ghosh Advaita , Lin Yen-Fu , Lin Shu-Ping
Published: August 2024

Neuromorphic devices represent a frontier in technological development, aiming to emulate the intricate parallel functionalities inherent to the human brain [1, 2]. Traditional computing models, such as Von Neumann architecture, grapple with limitations in parallel processing, prompting the exploration of neuromorphic computing to integrate memory and processing efficiently. Our research presents the double gate floating device based on Vander Waals heterostructure (DG-VH-FET), employing molybdenum disulfide (MoS2), hexagonal boron nitride (h-BN), and graphene (Gr) as key components. These devices, based on 2D materials, enable independent modulation of channel doping through electrostatic means [3].

In this study, we initially assessed the fundamental characteristics of the floating gate, including transfer characteristics, output characteristics, retention, and endurance. By applying constant drain-to-source voltages (VDS) while introducing variations in the back gate voltage (VBG) sweeping range, the memory window of the transfer characteristics changes. Conversely, maintaining a constant VBG and VDS while varying the top gate voltage (VTG) solely results in a shift in the threshold voltage of the memory window. This is attributed to the crucial role of VBG in charge trapping in the floating gate layer, with the influence of VTG on charge trapping being negligible due to the screening effect of MoS2 [4]. Moreover, by using VTG and VBG this study shows that DG-VH-FET could have potential applications in exploring and understanding various neurological effects, thereby bridging the gap between electronics and biology.

Figure 1
(Invited) Wearable Pocket-Sized Fully Non-Contact Cardiorespiratory Sensor
Authors: Wang Ting-Wei
Published: August 2024

Cardiovascular and respiratory diseases have emerged as the leading cause of global mortality over the past decade, encompassing conditions such as atrial fibrillation and chronic obstructive pulmonary disease. Consequently, continuous monitoring plays a crucial role in managing these conditions, as it enables early detection, improves patient survival rates, and alleviates the burden on emergency medical resources. Our research group has developed a wearable pocket-sized fully non-contact cardiorespiratory sensor that utilizes electromagnetic induction technology to measure dynamic changes in electrical conductivity resulting from cardiac contractions and pulmonary volume variations. This enables the continuous acquisition of eddy current damping response signals to achieve cardiorespiratory monitoring. In comparison to commercially available ECGs, PPG smartwatches, and respiratory sensors, our proposed pocket-sized sensor offers three major advantages: exceptional concealment, convenience, and comfort for health monitoring due to its pocket-sized and micro-structured design; simultaneous acquisition of two-dimensional cardiac and respiratory signals, facilitating comprehensive cardiorespiratory health monitoring; and the ability to adjust sensing depth through frequency modulation of the electromagnetic field, thus eliminating variations in physiological structures among subjects and achieving optimized sensing and personalized medical benefits.
Detection of Hydrogen Ions Resulting from the Inhibition of Acetylcholinesterase Using Indium Tin Oxide-Coated Nanostructures for Pesticide Sensing
Authors: Zeng Yi-Syuan , Wei Yu-Ting , Chao Yu-Chan , Lin Shu-Ping
Published: August 2024

The neurotransmitter acetylcholine (ACh) is hydrolyzed by acetylcholinesterase (AChE) into acetic acid and choline to terminate synaptic transmission (1). Organophosphorus (OPs) found in pesticides induce toxicity in organisms by irreversibly binding to AChE, leading to the phosphorylation of the serine residue at the active site. ACh cannot undergo hydrolysis by the phosphorylated enzyme, resulting in excessive stimulation of nerves and muscles, akin to a nerve agent (2). Our objective is to develop a rapid detection tool for determining the levels of pesticide residues in dairy products. In this study, we measured the release of hydrogen ions (H+) resulting from the hydrolysis of ACh by AChE, serving as an indirect method to evaluate the inhibitory effect of OPs on AChE. To detect the signals of H+ released during ACh decomposition, we used ITO-coated nanostructures modified with 3-aminopropyl trimethoxysilane (APTMS) as a sensing substrate integrated into the extended gate of a field-effect transistor (EGFET) biosensor. The amino group at the end of APTMS can bond with H+. By monitoring the changes in electrical signal from the EGFET biosensor, it is possible to know the concentration of H+ in the solution. The output characteristics (Id-Vd) of the APTMS-modified ITO-VASiNW EGFET were measured using ACh solutions at different concentrations. A correlation was observed between Id and ACh concentration within the tested range, exhibiting a sensitivity of 0.016 mA1/2 / mM and an R2 value of 0.9. A lower concentration of H+ indicates a more pronounced inhibitory effect on AChE by OPs and suggests higher levels of pesticide residues.

References

(1) Colović, M. B., Krstić, D. Z., Lazarević-Pašti, T. D., Bondžić, A. M., & Vasić, V. M. (2013). Acetylcholinesterase inhibitors: pharmacology and toxicology. Curr Neuropharmacol, 11(3), 315-335.

(2) Rajagopalan, V., Venkataraman, S., Rajendran, D. S., Vinoth Kumar, V., Kumar, V. V., & Rangasamy, G. (2023). Acetylcholinesterase biosensors for electrochemical detection of neurotoxic pesticides and acetylcholine neurotransmitter: A literature review. Environmental Research, 227, 115724.

Figure 1
(Invited) Probing Oxygen Intercalation, Oxidation and Chemo-Mechanical Coupling in OER Electrocatalysts
Authors: Akbashev Andrew
Published: August 2024

I will discuss how intercalation of O2- under OER conditions can lead to lattice oxygen redox and chemo-mechanical coupling inside the crystal lattice of a perovskite electrocatalyst. Specifically, I will show that high-resolution resonant inelastic X-ray scattering (RIXS) can detect the oxidation state of oxygen in a perovskite oxide. The emergence of oxidized oxygen depends on the transition metal and the amount of intercalated oxygen. At the same time, oxygen dimerization has a direct relevance to the stress-induced structural disorder that takes place inside the electrocatalyst. At the end, I will also discuss our recent finding in which oxygen can intercalate spontaneously following a catalytic O2 splitting at the surface and induce substantial transformations in the bulk of the perovskite.
Influence of Different Operating Conditions on Iridium Dissolution in a Proton Exchange Membrane Water Electrolyzer
Authors: Milosevic Maja , Winkelmann Leonard , Thiele Simon , Cherevko Serhiy
Published: August 2024

Polymer electrolyte membrane (PEM) water electrolysis plays a key role in the global decarbonization scheme by coupling the intermittent renewable energy sources to the production of high-purity hydrogen. Its deployment onto a GW scale, however, is hindered by the cost and availability of the precious metal catalysts utilized in today’s commercial systems, primarily by that of Ir used as the anode catalyst for the oxygen evolution reaction (OER). With the continuous increase in the demand for carbon-free hydrogen, drastic reductions from the current Ir loading of 1 – 2 mgIr cm-2 by at least an order of magnitude, without compromising the overall electrolyzer performance, are of crucial importance.1

In the recent years, significant efforts have been focused on understanding PEM electrolyzer degradation mechanisms and developing the necessary mitigation strategies, with a special focus being placed on the anode catalyst layer (CL).2-4 Recent results from our group showed that there are two main pathways for Ir to be removed from the anode CL: dissolution into the anode water line and transport through the membrane and the cathode CL.5 In the present work, we aim to shed light onto the effects influencing Ir dissolution under intermittent operation by quantitative analysis of the main Ir sinks within an electrolyzer and the determination of the charge of the dissolved Ir species.5, 6 Various accelerated stress tests with square-wave configuration aimed at accelerating Ir-based anode CL degradation were performed and the results were compared to those obtained during steady-state operation of the electrolyzer cell, which was used as a reference point. The influence of electro-diffusion, electroosmotic drag and Ir redeposition back to the ACL onto Ir dissolution were analyzed in detail to obtain deeper understanding on the Ir degradation processes.

M. Clapp, C. M. Zalitis, M. Ryan, Perspectives on current and future iridium demand and iridium oxide catalysts for PEM water electrolysis. Catal Today
420, (2023).

S. M. Alia et al., Electrolyzer Performance Loss from Accelerated Stress Tests and Corresponding Changes to Catalyst Layers and Interfaces. J Electrochem Soc
169, (2022).

Z. Q. Zeng et al., Degradation Mechanisms in Advanced MEAs for PEM Water Electrolyzers Fabricated by Reactive Spray Deposition Technology. J Electrochem Soc
169, (2022).

A. Weiss et al., Impact of Intermittent Operation on Lifetime and Performance of a PEM Water Electrolyzer. J Electrochem Soc
166, F487-F497 (2019).

M. Milosevic et al., In Search of Lost Iridium: Quantification of Anode Catalyst Layer Dissolution in Proton Exchange Membrane Water Electrolyzers. Acs Energy Lett
8, 2682-2688 (2023).

A. P. Dam, B. Y. A. Abuthaher, G. Papakonstantinou, K. Sundmacher, Insights into the Path-Dependent Charge of Iridium Dissolution Products and Stability of Electrocatalytic Water Splitting. J Electrochem Soc
170, (2023).
Understanding Mechanisms and Reversibility of Anode Degradation in PEM Water Electrolysis
Authors: Blair Sarah J. , Alia Shaun M , Padgett Elliot
Published: August 2024

Water electrolysis is an important route toward sustainable industrial production of hydrogen, as well as mitigation of the CO2 emissions associated with current hydrogen production from natural gas. The industrial deployment of clean electrolytic hydrogen will depend on long-term electrolyzer durability under the intermittent operating conditions associated with coupling with renewable sources of electricity. Thus, understanding cell degradation mechanisms is required to develop mitigation strategies and minimize performance degradation over extended periods of operation.

Here, we investigate the effect of temperature and intermittent conditions on proton exchange membrane (PEM) water electrolyzer performance over a variety of timescales. Performance losses consisting of both reversible losses and irreversible degradation accelerate quickly during holds at high current densities and low temperatures, reaching high cell voltages within several hours. However, the cell can be returned to near beginning-of-test performance by interrupting these current holds with a variety of intermittent states of operation, such as interruption of the applied current or operation at higher temperatures. Reversible losses can harm the overall cell efficiency without being captured in short-term polarization curves, and may also contribute to stressors causing long-term degradation. The impact of different shut-down and idle states on the catalyst layers and cell degradation will also be discussed. The presented insights could contribute to the development of accelerated stress test protocols as well as performance recovery strategies for long-term operation of PEM water electrolyzers.
(Invited) Electron Microscopy Investigation of PEM Electrolyzer Degradation at Low Iridium Loadings
Authors: Yu Haoran , Cullen David A. , Serov Alexey , Chan Ai-Lin , Padgett Elliot , Alia Shaun M , Parrish Chance , Mauger Scott A , Li Kui , Komini Babu Siddharth , Myers Deborah J. , Mukundan Rangachary
Published: August 2024

The employment of hydrogen as an energy carrier provides a promising solution toward zero carbon emission and battling climate change. To meet the DOE’s Hydrogen Shot goal of $1 per kilogram of hydrogen by 2031, proton exchange membrane (PEM) water electrolysis is a key technology of hydrogen production from renewable energy sources. Successful deployment of PEM electrolyzers requires reducing cost while simultaneously improving performance and lifetime. While cost reduction is expected from a variety of strategies including scaling up, operation optimization, and advanced manufacturing, it remains vital to reduce the use of noble-metal catalyst due to its scarcity and vulnerable supply chain subject to market disturbance. [1]

Reducing the loading of iridium catalyst on the anode while maintaining electrolyzer performance and durability is of great challenge. In this talk, we discuss issues in PEM electrolyzer component development and advanced manufacturing of electrode layers related to catalyst loading reduction with an emphasize on analytical electron microscopy which provides valuable insight on materials morphology, crystalline structure, and chemical compositions. The batch-to-batch variance of catalyst morphology and elemental composition/distribution from commercial suppliers will be examined for catalyst down-selection. We then analyze the effect of reducing Ir loading on the electrode layer structure and ionomer distribution. These results are correlated with electrochemical measurements in the electrolyzer cell, which help elucidate the effect of low catalyst loading on electrolyzer performance. Morphologies of degraded low-loading anode catalyst layer and gas recombination layers will be investigated, and the dissolution and migration of iridium will be studied. We will also examine impact of different roll-to-roll manufacturing strategies for low-loading catalyst layers and on electrolyzer durability. Last but not least, we analyze MEAs subject to cation contamination and recovery procedure with electron microscopy. [2]

References

[1] Alia, S.M., Current Opinion in Chemical Engineering 2021, 33:100703.

[2] Funding for this work was provided by U.S. Department of Energy Office of Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office through the H2NEW Consortium. Electron microscopy research conducted as part of a user project at the Center for Nanophase Materials Sciences (CNMS), which is a US Department of Energy, Office of Science User Facility at Oak Ridge National Laboratory.
Understanding Performance Limitation of Liquid Alkaline Water Electrolyzers
Authors: Wang Guanzhi , Tricker Andrew W. , Mukundan Rangachary , Peng Xiong
Published: August 2024

Green hydrogen production via water electrolysis powered by renewable energy is a critical technology in the pursuit of a net-zero emission economy1. Liquid alkaline water electrolyzers (LAWEs), being the most commercially mature electrolyzer technology, play a pivotal role in large-scale green hydrogen production2. The utilization of earth-abundant and cost-effective nickel and iron-based materials as cell components of LAWEs reduces capital cost of large-scale electrolyzer cells3. However, LAWEs suffer from low operational efficiency, primarily due to low intrinsic activity of unoptimized electrode materials, as well as high ohmic resistance introduced by separators and gas bubbles within thick electrodes. Herein, we used a lab-scale LAWE cell in combination with various electrode configurations to gain a deeper understanding of the limiting factors affecting conventional LAWE performance. Our results show that the electrochemical active surface area (ECSA), chemical compositions, and pore structure of the electrodes are key design parameters to achieve high efficiencies for advanced LAWEs. Besides, particular attention should be paid to the micro-gaps in between electrode and separator, which can be minimized through using electrodes with lower surface porosity and smaller pore size. Consequently, these enabled us to build LAWEs that are capable of sustaining 2 A cm-2 at 2.2 V and operating steadily at 1 A cm-2 for nearly 600 h with negligible performance decay. These findings establish essential criteria for selecting electrodes to achieve high-performance in LAWE and, in turn, expedite the adoption of LAWE technology in green hydrogen production and the transition towards a low-carbon economy.

Acknowledgement

The authors acknowledge the Department of Energy-Office of Energy Efficiency and Renewable Energy-Hydrogen and Fuel Cell Technologies Office (DOE-EERE-HFTO) and the H2 from Next-generation Electrolyzers of Water (H2NEW) consortium for funding under Contact Number DE-AC02-05CH11231.

References:

Pivovar, N. Rustagi and S. Satyapal, The Electrochemical Society Interface, 27, 47 (2018).

Ayers, N. Danilovic, R. Ouimet, M. Carmo, B. Pivovar and M. Bornstein, Annual review of chemical and biomolecular engineering, 10, 219 (2019).

David, C. Ocampo-Martínez and R. Sánchez-Peña, Journal of Energy Storage, 23, 392 (2019).
Polymorphic Engineering of MnO2 Structure as a Diffusion Blocking Layer for Selective Seawater Electrolysis
Authors: Gupta Prashant Kumar Kumar , Bishwanathan Shashwat
Published: August 2024

The water splitting via renewable energy is one of the sustainable process to generate the future clean energy in form of hydrogen. One of the key challenge for the large-scale water electrolysis is the availability of pure water. The sweater can be consider as an alternate feedstock for the large-scale water electrolysis. However, the presence of undesirable components like chlorides, bromides etc. are the potential challenge to make the use of seawater as a facile feedstock. As per the electrochemical potentials, chlorine evolution reaction (CER) along with the oxygen evolution reaction (OER) at the anode is one of the primary existing challenge in seawater electrolysis. Where thermodynamics favour OER and kinetic benefits, the CER process with two-electron transfers reaction. As of now, precious noble metal catalysts such as ruthenium and iridium-based oxides have been explored as a catalyst for seawater electrolysis. However, their high cost does not recommend the use of these catalysts for the large-scale production and limits its commercialization. Here, we are exploring the non-precious Mn based catalyst for OER vs. CER and make make seawater electrolysis as a commercial favourable process. We have explored various polymorphs of MnO2, such as α, β, γ, and δ-MnO2, considering the MnO2 as diffusion blocking layer for the selective OER process during the seawater electrolysis. The polymorphic engineering provide the window to tune the catalytic properties to make it selective towards the OER. Further, the results suggest that α- and β-MnO2 are OER selective however, the γ-, and δ- MnO2 are CER selective. We have identified the reaction mechanism using various electrochemical tools and shown the structure-activity-selectivity trends for the polymorphic structure of MnO2.
(Invited) CA Hydrogen Hub and Advanced Electrolysis R&D at LBNL
Authors: Weber Adam Z.
Published: August 2024

Widespread use of hydrogen energy is contingent on the development of reliable and economical sources of hydrogen. This is seen in DOE’s Hydrogen Energy Earthshot goal of production of hydrogen of $1 per 1 kg in 1 decade, as well as the Regional Hydrogen Hub Program. Endemic to reaching these cost metrics using renewable, clean electricity as a feedstock is the use of electrolysis. Prime among the electrolysis technologies are those utilizing ion-conducting polymers (ionomers) including polymer-electrolyte water electrolyzer (PEWE), high-temperature solid-oxide electrolyzer (SOEC), and those using liquid alkaline systems (LAWE). However, these technologies need to exhibit increased efficiency, (dynamic) performance, and durability to reduce costs and be commercially viable. In this talk, we will overview some of these technologies through the lens of recent advances at Lawrence Berkeley National Laboratory.

In addition, key to enabling a hydrogen ecosystem is the deployment of various hydrogen technologies at scale in resilient and sustainable system. Recently, the Alliance of Renewable Clean Hydrogen Energy Systems (ARCHES), a collective representing the CA region, was selected for negotiation with DOE as a hydrogen hub. In this talk, an overview of ARCHES and its approach will be given.

Finally, like most electrochemical devices, PEWEs involve multiple components (e.g., catalyst, ionomer, transport layers, membrane, plates) and multiple phases, with phenomena occurring across different time and length scales. Key in PEWE technologies is the interface between the ionomer and the catalyst. In this talk, time-permitting, recent results from the Center for Ionomer-based Water Electrolysis (CIWE) will be introduced including the description of interfacial properties and double layers at this interface.
(Invited) Growing Production Capacity in PEM Electrolysis: Learnings and Technical Accomplishments
Authors: Ayers Katherine E. , Capuano Christopher B. , Carmo Marcelo , Dalton Luke T.
Published: August 2024

Development of hydrogen production capacity with low carbon intensity (low carbon dioxide emissions) is an essential part of reaching global sustainability targets and mitigating long term climate change. While electrolysis has been commercial for decades, many applications have been smaller scale, and only a small fraction of the total hydrogen production is made from water rather than methane. In the US, there have also now been 7 Hubs selected which each have minimum targets of 50 metric tons of low carbon hydrogen production per day. The only way to meet these capacities in the near term is with proven commercial technologies such as liquid alkaline and proton exchange membrane (PEM) electrolysis. However, even though PEM technology has been commercial for decades, it has only recently reached megawatt scale, and most “gigafactories” that have been announced are not completely built out or staffed for these demands. It is therefore essential that PEM developers scale manufacturing capacity of cell stacks significantly in the next few years.

Experience in commercial installations, manufacturing, and previous scale up are critical to success. Nel Hydrogen US has successfully scaled up cell stack active area by almost 2 orders of magnitude from its earliest products, and has gained decades of real world experience in how different field operation can be from controlled internal tests. The smaller platforms also offer built in verification testing for new designs and manufacturing methods. This talk will discuss Nel’s stack scale up journey, as well as updates on current expansion efforts.
(Invited) Towards the Next Generation of High Performance, Durable Water Electrolyzer Membranes
Authors: Park Andrew M , Gebhardt Ryan , Vander Woude Meghan , Wright Ben , Plymill Austin , Arslan Funda , Gurau Marc
Published: August 2024

Proton exchange membrane water electrolysis (PEMWE) has emerged as one of the most promising methods to produce clean hydrogen at industrial scale. Incumbent membranes (such as Nafion™ N115) have proven to enable high durability in the PEMWE application. However, it is well understood that novel PEMWE stack designs require higher voltage efficiency and low effective gas crossover, which implies thin, low resistance membranes containing gas recombination catalysts (GRCs). Compared to Nafion™ N115, thin membranes are at enhanced risk of failure from both mechanical and (electro)chemical mechanisms. While promising examples of these membranes have been recently disclosed,1 a systematic demonstration of their durability has not yet been performed.

In PEM fuel cells, decades of research have resulted in accelerated stress test (AST) protocols that are effective to mimic real failures while shortening the time to observe them. These ASTs have not yet been proven/implemented for PEMWE membranes. Progress toward engineering high performance, durable thin membranes will be presented, along with a perspective on how best to engineer ASTs for PEMWE.

Park, A., Performance and Durability Investigation of Thin, Low Crossover Proton Exchange Membranes for Water Electrolyzers. DOE Annual Merit Review. 2020.
Comprehensive Effort on Electrode Slurry for Proton Exchange Membrane Water Electrolysis
Authors: Kim Jung Ho , Lee Ju Sung , Lim Youngjoon , Park Hyun Jin , Baek Jisuk , Kim Hee-Tak , Kim Jun Young
Published: August 2024

Green hydrogen production through renewable energy-based water electrolysis is the most efficient technology for decarbonization, and demand has recently been rapidly increasing. Addressing this surge in demand requires the rapid development of reliable large-scale manufacturing methods for PEMWE membrane-electrode assemblies (MEAs).

For reliable large-scale manufacturing, it is necessary to optimize electrode components, including catalysts, binders, solvents, and additives, as well as their dispersion methods. Particularly, ensuring the homogeneity and stability of the electrode slurry is crucial.

In this study, we enhanced the stability of the electrode slurry to twice and five times that of the existing standard by selecting an appropriate dispersion method for the metal-oxide oxygen evolution reaction (OER) catalyst and by adjusting the OER catalyst (both support and particle size control), respectively. Additionally, we secured stable electrode coating characteristics by controlling the solvent composition and additives, based on the rheology of the slurry. By optimizing the composition, formulation, and preparation method of the electrode slurry to form an optimal catalyst layer, we achieved a 20% improvement in performance compared to commercial MEA products.
Activated Migration of Hydroxide Ion in Anolyte for Enhancing Performance of Scaled-up Non-Noble Catalysts in Pure Water-Fed Anion Exchange Membrane Water Electrolysis
Authors: Bae Sooan , GIM Han-Gyoul , Kim Yeongin , Lee Jaewon , Lee Kiyoung , Choi Jinsub , Lee Jaeyoung
Published: August 2024

The continuous advancement in water electrolysis technologies has illuminated the potential of sustainable energy sources, particularly in the realm of green hydrogen production. Anion exchange membrane water electrolysis (AEMWE) stands out as a promising technology capable of theoretically yielding high-purity hydrogen. However, the commercialization of AEMWE faces challenges arising from the inherent discord between high performance and the elevated costs associated with noble metal catalysts, such as platinum and iridium. Moreover, prevalent studies often focus on a limited electrode area of less than 4 cm2, thereby restricting the exploitation of the high purity hydrogen production capabilities inherent in AEMWE. This research prioritizes the enhancement of performance through a meticulously crafted membrane-electrode assembly (MEA) employing a 25 cm2 Ni-frame caged NiMoO4 catalyst for cathode synthesis. The observed performance improvement is attributed to the augmented active site of the catalyst, consisting of NiMoO4 entrapped in the Ni substrate during the compression process of the electrode. Additionally, the increase in local pH at the interfacial between electrode and bulk electrolyte is facilitated by the capillary phenomenon resulting from the space between the Ni substrate and the NiMoO4 catalyst layer, leading to enhanced migration of the electrolyte containing hydroxide ions.

Acknowledgements

This research was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resources from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20213030040590).
(Invited) Mechanical Properties of Proton Exchange Membranes for Water Electrolysis Applications
Authors: Novy Melissa , Wilcox Kieron , Humphris Mark Jason , Yandrasits Michael
Published: August 2024

Water electrolysers are critical to the advancement of sustainable hydrogen technologies. A key component of proton-exchange membrane water electrolysers (PEMWE) is the ionomer membrane which transports protons and water from the anode to the cathode and physically separates the H₂ and O₂ reaction products. Importantly, the barrier properties of the membrane must be maintained at high differential pressure over the lifetime of the PEMWE. To help predict the mechanical durability and operational safety of the PEMWE, it is important to understand the mechanical properties of the PEM as a function of temperature, differential pressure, and time.

The main component of a typical modern PEM is a perfluorosulfonic acid (PFSA) ionomer. PFSAs have a hydrophobic perfluorinated backbone with pendant perfluorinated side chains terminating in sulfonic acid groups. The general chemical structure of PFSAs is understood to result in phase separation into hydrophilic, sulfonate-rich domains that act as transport pathways and hydrophobic, tetrafluoroethylene-rich domains that impart thermomechanical stability. In PEMWE applications, short-side chain PFSAs are a promising alternative to the benchmark Nafion, a long-side chain PFSA. At a given ion-exchange capacity (IEC), the ratio of perfluorinated backbone to sulfonic acid side chain increases as the side chain length decreases. Thus, short-side chain PFSAs may be more thermomechanically stable while maintaining good proton and water transport necessary for PEMWE efficiency.

In this work, the mechanical properties of short-side chain PFSAs are investigated as a function of IEC, temperature, differential pressure, and time. Particular focus is given to compressive mechanical measurements to simulate the conditions experienced by the membrane in PEMWE applications. The findings are expected to help inform the design of next-generation membranes for hydrogen technology applications.
Enhancing Impregnability in Reinforced Composite Membrane Using Greener Dispersion
Authors: Park Hyun Jin , Lim Youngjoon , Lee Ju Sung , KIM Jungho , Baek Jisuk , Lee Albert S , Kim Hee-Tak , Kim Jun Young
Published: August 2024

Perfluorosulfonic acid (PFSA) polymer commonly offer high ionic conductivity, chemical and physical properties, and rapid response, making them widely used in energy conversion technologies like fuel cell and water electrolysis. Industrial commercialization of the polymer electrolyte membranes for water electrolysis depends not only on sufficient electrochemical performance but also requires gas barrier properties and high dimensional stability. To improve the properties of these polymer electrolyte membranes selection of an appropriate dispersion solvent and optimization of its composition ratio are very important. However, PFSA polymer limits the types of dispersion solvents due to its unique structure, which consist of combining a hydrophilic perfluorovinyl ether side chain with sulfonate groups onto a hydrophobic tetrafluoroethylene backbone.

Here, we have introduced a new greener mixture system for the fabrication of PFSA-reinforced composite membranes for water electrolysis and compared it with conventional solvent systems. Our solvent system not only produced a more densely packed support layer but also relaxed the anisotropy of the reinforced composite membrane. As a result, the compressive strength and tensile strain increased, making it possible to compensate for the shortcomings caused by the support. Also, this increased impregnability resulted in relatively low gas permeability and high ionic conductivity. The water electrolysis performance was comparable with those prepared using an NMP-based solvent. These results demonstrate a method for preparing PFSA dispersions for reinforced composite membrane and their potential to replace hazardous solvents used in fabrication processes.
Development of Fe-Doped Ni2P-POx Electrocatalyst for Oxygen Evolution Reaction
Authors: Park Sunjin , Singu Bal Sydulu , Mandal Debasisi , Kim Hansung
Published: August 2024

Water electrolysis is extensively researched as a next-generation energy storage method to overcome the intermittency of renewable energy. Electricity generated from renewable sources such as solar and wind power can be converted into pure green hydrogen through water electrolysis. Despite the potential of green hydrogen as a renewable energy storage/carrier medium, the high overpotential resulting from the slow kinetics of oxygen evolution reaction (OER) and the use of expensive noble metals make cost-competitive hydrogen production a significant challenge. Anion exchange membrane water electrolysis (AEMWE) is one method for hydrogen production, offering economic advantages over proton exchange membrane systems as it allows for the use of relatively inexpensive transition metal catalysts like Ni, Fe, and Co due to its alkaline environment.

Nickel phosphide (Ni2P)-based catalysts have emerged as highly promising candidates to accelerate the electrocatalytic OER. In particular, the introduction of Fe into Ni2P has been found to induce charge transfer, optimizing the electronic structure and accelerating the OER process. OER catalysts based on transition metal phosphides often exhibit a core-shell structure with phosphide at the core and oxide at the shell during OER measurements. This core-shell structure enhances OER performance through the oxide shell, complementing the deficient electrical conductivity of the phosphide core, resulting in superior catalytic activity and durability. From this perspective, transition metal phosphates are also being studied as electrocatalysts for OER. Phosphates, such as PO3
-, not only promote oxygen adsorbate adsorption but also induce a distorted local metal center geometry that favors OH- adsorption and further oxidation.

To address these challenges, this study develops a facile and scalable synthesis of iron-doped nickel phosphide-phosphate (Fe-doped Ni2P-POx) nano-hybrid system as a superior noble-metal free OER powder-catalyst. The utilization of self-filling and pyrolysis approaches facilitates economically viable production of the highly porous phosphide catalyst with a high specific surface area and rough surfaces. X-ray diffractometer, X-ray photoelectron spectroscopy, and electron paramagnetic resonance elucidates the electronic structure modulation, resulting in phosphide-phosphate nano-hybrid structures. Consequently, the catalyst demonstrates excellent OER activity in 1 M KOH, with a significantly low overpotential of 283 mV at 20 mA cm-2, a small Tafel slope of 28.4 mV dec-1, and a superior exchange current density of 8.22 mA cm-2, surpassing state-of-the-art PGM catalysts. Furthermore, its durability over 20 hours indicates its excellent stability, mass transport properties, and mechanical robustness in alkaline media, underscoring its potential as an efficient OER catalyst to facilitate electrocatalytic hydrogen production.

Figure 1
Investigating Corrosion Degradation of Porous Transport Layers for PEM Water Electrolyzers Using on-Line ICP-MS
Authors: Kariuki Nancy N. , Dang Ngoc K , Myers Deborah J.
Published: August 2024

The degradation of polymer electrolyte membrane water electrolyzer (PEMWE) is the net result of degradation phenomena across each component, which includes structural changes to the catalyst layer, deactivation of the electrolyte, loss of performance due to impurities in the feed water, and the corrosion and passivation of titanium-based bipolar plates (BPPs) and porous transport layers (PTLs).1, 2 This presentation will focus on PTL degradation, which has received relatively little attention compared to loss of performance related to catalyst and electrode degradation mechanisms. Generally, PTL degradation can be categorized into chemical/corrosion degradation and mechanical degradation. 3 In this work, we focus on corrosion degradation of the anode PTL. Titanium (Ti) is the state-of-the-art material for PTLs due to its stability and intrinsic electrical conductivity. Ti can however, develop an oxide layer in the harsh oxidizing conditions of the anode, thus reducing the effective electrical conductivity and cell performance. Coating the Ti parts with platinum group metals (Pt or Ir) is often used to protect against oxidation.4

An electrochemical flow cell system connected to an inductively-coupled plasma-mass spectrometer (ICP-MS) capable of detecting trace concentrations (<ppb) of dissolved elements in solution has been used to investigate the corrosion rates of the Ti-PTLs with and without coatings toward understanding factors influencing degradation mechanisms. The influence of various parameters such as potential, potentiodynamic profile parameters (e.g., scan rate, upper and lower potential limits), electrolyte type, and pH on the corrosion processes has been investigated.

References

Feng, X. Yuan, G. Liu, B. Wei, Z. Zhang, H. Li, H. Wang, J. Power Sources 2017, 366, 33.

Babic, M. Suermann, F. N. Büchi, L. Gubler, T. J. Schmidt, J. Electrochem. Soc. 2017, 164, F387.

Park, H. Oh, T. Ha, Y.I. Lee, K. Min, Appl. Energy 155 (2015) 866-880.

Rakousky, U. Reimer, K. Wippermann, M. Carmo, W. Lueke, D. Stolten, J. Power Sources 326 (2016) 120–128.

Acknowledgements

This research is supported by the U.S. Department of Energy, Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office under the auspices of the H2NEW consortium. Argonne National Laboratory is managed for the U.S Department of Energy by the University of Chicago Argonne, LLC under contract DE-AC-02-06CH11357.
Design and Preparation at Scale of Ternary NiFe-M-Ox (M=Co, Mo) Catalysts for OER in Alkaline Media
Authors: Serov Alexey , Lyu Xiang , Yu Haoran , Cullen David A.
Published: August 2024

Due to scarcity of Platinum Group Metals (PGMs) widely used in low temperature water electrolysis as cathodes (Hydrogen Evolution Reaction; HER) and anodes (Oxygen Evolution Reaction; OER) a boosting interest to their substitution to Earth abundant elements is observed. It was successfully demonstrated that elements like iron, nickel, cobalt and other (in their oxide and hydroxide forms) can be effective OER catalysts when operate at high pH ranges from 12 to 14 [1-3].

This work is devoted to systematic investigation of influence of third element addition to NiFeOx system on a performance and stability of catalysts in alkaline OER. As a co-catalytic elements Mo and Co were selected, based on our previous experience [4,5]. A systematic study on an effect of NiFe-to-M ratio, concentration of precipitation agent and post-treatment temperature were evaluated in a wide range of parameters. Taking into account that mass loading of PGM-free OER catalysts is substantially higher than iridium/ruthenium once and can be up to several milligrams per cm2 all experiments were designed to be scalable. In a laboratory scale reactor, a fascinating batch size of 25g was achieved, using minimal amount of water-based solvents in order to minimize a waste stream generated. Presentation will discuss characterization of obtained materials by SEM, TEM, XPS, XRD and other methods as well as their performance, stability and durability in alkaline conditions, studying Oxygen Evolution Reaction.

Acknowledgements and Statements.

The authors acknowledge financial support from H2NEW and ElectroCat consortia.

References.

[1] X. Lyu, J. Li, J. Yang, A. Serov "Significance of Slight Ambient Temperature Variation on the Electrocatalyst Performance toward Oxygen Evolution Reaction" Journal of Environmental Chemical Engineering (2023).

[2] X. lyu, A. Serov “Cutting-edge methods for amplifying the oxygen evolution reaction during seawater electrolysis: a brief synopsis” Ind. Chem. Mater., (2023).

[3] X. Lyu, Y. Bai, J. Li, R. Tao, J. Yang, A. Serov "Investigation of oxygen evolution reaction with 316 and 304 stainless-steel mesh electrodes in natural seawater electrolysis" J. of Environmental Chemical Engineering 11 (2023) 109667.

[4] A. Serov,N. I. Andersen, A. J. Roy, I. Matanovic, K. Artyushkova, P. Atanassov “CuCo2O4 ORR/OER Bi-Functional Catalyst: Influence of Synthetic Approach on Performance”, J. of The Electrochem. Soc. 162 (4) (2015) F449-F454.

[5] N. I. Andersen, A. Serov, P. Atanassov “Metal Oxides/CNT Nano-Composite Catalysts for Oxygen Reduction/Oxygen Evolution in Alkaline Media”, Appl. Catal. B: Environmental 163 (2015) 623-627.