bluuebunny/crossref_metadata_2025_split huggingface dataset:
(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.
(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
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.
(Invited) OER Active Phases, Catalytic Mechanism and Reaction Centers of Ni (oxy)Hydroxide with and without Fe Impurities
Authors: Zhu Jing , Dionigi Fabio , Li Wei-Xue , Greeley Jeffrey , Strasser Peter , Zeng Zhenhua 
Published: August 2024

Identifying atomic-scale structures of catalytically active phases, catalytic mechanism and reaction centers are crucial for establishing rigorous structure-activity relationship of highly active catalysts and for designing new catalysts with further improved performance. Due to the lack of theoretical guidance and challenges in experimental structural characterization during OER conditions, in-situ structures and stabilities of two (a-Ni(OH)2 and g-NiOOH with water and ion intercalation) out of four (oxy)hydroxide phases (another two are b-Ni(OH)2 and b-NiOOH without water and ion intercalations) remain elusive after at least half a century study, which has hindered the establishment of rigorous structure-activity relationship of Ni (oxy)hydroxides and their derivatives for the OER. As a consequence, it is still unclear regarding which phases should be the hosts and the precursors of choice for highly active catalysts. Here, by combining ab initio molecular dynamics simulation, in-situ wide-angle X-ray scattering, and electrochemical measurements, we provide direct atomic-scale and self-consistent insights into the crystal structure, water and ion intercalation, and stable potential windows of complex a-Ni(OH)2 and g-NiOOH with respect to b-phases. DFT calculations indicate that b-NiOOH and g-NiOOH with Fe impurities have similar OER activity to or even higher OER activity than that of g-NiFe LDH, with a dependence on the Fe coverage on the edges. Current work suggests that both b-NiOOH and g-NiOOH are potential hosts of highly active OER catalysts, which enlarges the phase space for the design of OER catalysts with further improved performance.
We will discuss the implications of the above insights toward understanding of the active phases, reaction centers and catalytic mechanism of NiM and CoM layered double hydroxides. If time permits, we will further review our work our work regarding the promotion effects of non-covalent ligand-oxide interaction in OER and mitigation of RuO6 octahedron distortion by enhanced A-site electronegativity in pyrochlore for acidic water oxidation.
References:

Nature Communications 2020, 11, 2522

Angew. Chem., Int. Ed. 2021, 60, 14446

Journal of Materials Chemistry A 2022, 10, 9419

Nature Communications 2023,14, 997
Statistical Investigation of the Reproducibility of Stack Components in a PEM Water Electrolyzer
Authors: Hoppe Eugen , Janssen Holger , Müller Martin Johannes 
Published: August 2024

To achieve homogeneous conditions throughout a single cell of a stack and within a stack and furthermore within several stacks, the components assembled in a stack should be reproducible to achieve a homogeneous performance. To evaluate how reproducible the stack components are, the porous transport layers, the expanded metals sheets, the perforated metal sheets, and the flow field plates from a 5-cell stack were examined.
Eight samples were cut out of each of the 450 cm² layers, and a height profile (area: 10 x 10 mm) was recorded using a laser scan. From the height profile, the roughness values Ra (arithmetic average) and Rz (maximum peak to valley height) could be derived as well as the curvature of the samples (see Figure 1). Figure 1a) shows a contour plot of a perforated metal sheet. There is a height difference of up to 20 µm from the edge to the center of the sample. For the stack assembly this means an initial force is required to flatten the sheet before the actual compression of the stack takes place. Figure 1b) shows the roughness values Ra and Rz. The values vary within the sample (Ra: ± 3.8 µm, Rz: ± 5.7 µm) and throughout the samples (Ra: ± 1.4 µm, Rz: ± 2.5 µm). Further, the thickness of the components was measured, and the variation was calculated. In terms of stacking the components, as done in the stack, the best and worst case were calculated. The aim of this study was to determine input parameters for follow-up tests for the mechanical and electrical characterization of the components as especially the roughness of the components may have a significant impact on the contact resistance.

Figure 1
Diffusion-Bonded Unitized Anode Assemblies for PEM Electrolysis Stacks
Authors: Steele James , Gosselin Sean , Papandrew Alexander B 
Published: August 2024

Hydrogen generation via proton exchange membrane (PEM) water electrolysis is in the midst of a technological renaissance aimed at achieving cost parity with steam reforming within the decade. Reaching that plateau will require substantial system cost reductions accompanied by increased performance of the cell stack module. Many proposed improvements to the cell stack draw from the established principles of electrochemical and manufacturing engineering, targeting lower component resistances while lowering part count and enhancing ease of assembly, respectively.
The PEM electrolyzer anode assembly (comprising the porous transport layer (PTL) and the anode flow field) is suited for just such a revision. In practice, the anode PTL is positioned on a metallic bipolar plate that is machined or embossed with a flow field, or the PTL is joined to an assemblage of thin macroporous media that serves as a flow field1. In both cases, the interfacial resistances between the subcomponents of the assembly are non-negligible and are conventionally mitigated by applying noble metal coatings, typically Pt.
In this contribution, we investigate alternatives to conventional assemblies via diffusion bonding. Using thermal treatments, the porous transport layer is joined to the anode flow field, yielding a robust, atomic-scale metallurgical bond. We demonstrate the manufacturing of large-format assemblies in multiple configurations, using either stacked microporous media or grooved plates, meeting tight tolerances for thickness across their span. We also show that the bulk-like character imparted to the assembly obviates the need for antipassivation coatings at the critical interfaces between components, evinced by low series resistance in both ex situ and in situ electrolysis cell tests.
References
(1) Dristy, M. E. Proton Exchange Membrane Electrochemical Cell System. US7270908B2, September 18, 2007.