bluuebunny/crossref_metadata_2025 huggingface dataset:
Coating Applications By Pulse/Pulse Reverse Electrolysis
Authors: Hall Timothy , Garich Holly , Wang Dan , Vijapur Santosh Hanamant , Radhakrishnan Rajeswaran , Le Huong , Snyder Stephen , Inman Maria , Taylor Earl Jennings
Published: February 2024

Faraday Technology Inc. is a research, development and electrochemical engineering firm developing electrochemical innovations based has pulse/pulse reverse electrolytic principles. [1,2] With that founding basis Faraday has been able to bridge the gap between academic understanding and small-scale demonstrations to commercialization of practical components for over 32 years of operation.

This presentation will discuss a broad range of electrodeposition studies including single metal, alloy, composite and electrophoretic. We will highlight some of the key factors that determine the usefulness and successfulness of using pulse/pulse reverse principles to apply materials to a broad range of structures. For instances, we will discuss additive free Cu deposition into a microvia, functionally graded NiMo coatings from a single electrolyte, graphene incorporation into a Cu film, and electrophoretic deposition of CNTs. Each process utilized pulse/pulse reverse plating to overcome key challenges with diffusion, stress, composition, adhesion, and functional properties.

References:

J. Taylor “Adventures in Pulse/Pulse Reverse Electrolytic Processes: Explorations and Applications in Surface Finishing” J. Applied Surface Finishing,
3(4), 178-189 (2008).

J. Taylor, et al., (2019; Chapter 7) “Breaking the Chemical Paradigm in Electrochemical Engineering: Case Studies and Lessons Learned from Plating to Polishing” R.C. Alkire (Volume 18). Electrochemical Engineering: The Path from Discovery to Product.Wiley-VCH.
Reverse Pulse Plating of Thick and Crack-Free Magnetic Layers for MEMS Manufacturing
Authors: Bernasconi Roberto , Cesaro Riccardo , Rinaldi Christian , Magagnin Luca
Published: February 2024

The integration of hard magnetic alloys in the form of thick films is one of the most interesting challenges for the manufacturing of energy efficient magnetic microelectromechanical systems (MEMS) [1]. With respect to current state of the art devices, whose working principle mostly relies on the exploitation of Lorentzian forces, MEMS based on permanent magnets can potentially present lower power consumption, larger displacements and stronger actuation forces. However, despite these attractive advantages, it is generally difficult to integrate thick hard magnetic layers with currently employed MEMS fabrication techniques.

Electrodeposition is a technique that is compatible with MEMS fabrication and is characterized by many significant advantages: high deposition rates, no necessity of a vacuum system, low cost, possibility to deposit alloys and composites. Despite of these advantages, electrodeposition methods capable to yield the thick hard magnetic films suitable for MEMS sensors/actuators have not been successfully developed yet. The reason resides in the problems typically encountered in the deposition of hard magnetic alloys: high residual stress, presence of cracks and inadequate surface finishing.

In this context, Reverse Pulse Plating (RPP) may constitute a possible solution to address the challenges of hard magnetic alloys electrodeposition [2]. This technique can significantly reduce internal stresses and hydrogen embrittlement, inhibiting thus cracks formation. In addition, it can simplify electrolyte formulation, eliminating the need of excessive amounts of additives. Finally, it can enhance magnetic properties and refine the grain structure of the deposits, resulting in better mechanical properties.

In the present work, RPP of thick and crack-free layers of CoNiP and CoPtP is investigated. These two materials are between the most studied for potential MEMS applications [3, 4]. Indeed, whereas CoPtP offers high coercivities (> 3000 Oe) and excellent remanences, CoNiP represents a low cost alternative characterized by good magnetic properties (with HC up to 2000 Oe). Co-rich CoNiP and CoPtP are deposited from a chloride based acidic electrolyte [3] and from a tartrate based bath, respectively, using ultra-fast RPP. The resulting coatings, characterized by thickness up to 20 µm, are characterized to assess their morphology, phase composition and magnetic behavior.

[1] N. M. Dempsey, “Hard Magnetic Materials for MEMS Applications” in: Nanoscale Magnetic Materials and Applications, Springer, Boston, MA (2009)

[2] S. Pané et al., Electrochim. Acta 56, 8979-8988 (2011)

[3] D. Y. Park et al., Electrochim. Acta 47, 2893-2900 (2002)

[4] D. Mallick et al., J. Appl. Phys. 125, 023902 (2019)
Pulse/Pulse Reverse Electrolysis for Electrochemical Conversion Technologies
Authors: Hall Timothy , Lee Katherine , Vijapur Santosh Hanamant , Garich Holly , More Santosh R , Snyder Stephen , Inman Maria , Taylor Earl Jennings
Published: February 2024

Faraday Technology Inc. is a research, development and electrochemical engineering firm developing electrochemical innovations based has pulse/pulse reverse electrolytic principles. [1,2] With that founding basis Faraday has been able to bridge the gap between academic understanding and small-scale demonstrations to commercialization of practical components for over 32 years of operation.

This presentation will discuss techniques where pulse/pulse reverse operation enabled improved production rates, reduced energy demand, eliminated biofouling, and enabled recycling of complex structures. We will highlight some of the key factors that determine the usefulness and successfulness of using pulse/pulse reverse principles to improve process control of the electrochemical operations. For instances, we will discuss electrochemical destruction of PFAS, electrocatalytic operations, and carbon fiber recovery from composites.

References:

J. Taylor “Adventures in Pulse/Pulse Reverse Electrolytic Processes: Explorations and Applications in Surface Finishing” J. Applied Surface Finishing,
3(4), 178-189 (2008).

J. Taylor, et al., (2019; Chapter 7) “Breaking the Chemical Paradigm in Electrochemical Engineering: Case Studies and Lessons Learned from Plating to Polishing” R.C. Alkire (Volume 18). Electrochemical Engineering: The Path from Discovery to Product.Wiley-VCH.
Lightweight and Efficient: Exploring Low-Weight Bipolar Plates for Alkaline PEM Fuel Cells
Authors: Rojo Osorio Santiago , Sanchez-Saenz Carlos Ignacio
Published: February 2024

Alkaline proton exchange membrane (PEM) fuel cells have the potential to be highly efficient and environmentally sustainable energy sources. However, the performance and durability of these fuel cells are dependent to some extent on the bipolar plates used in their design. Bipolar plates play a crucial role in the electrochemical reactions within the fuel cell, and their design and material selection can greatly impact the efficiency and lifespan of the fuel cell.

This study focuses on three key aspects of developing efficient and durable bipolar plates for alkaline PEM fuel cells. Firstly, the study emphasizes the importance of optimizing bipolar plate design and flow field to enhance the power output and limiting current density of the fuel cell. Computational fluid dynamics (CFD) simulations are employed to optimize the flow field design, which is found to be crucial in determining the performance of the fuel cell. The optimized flow field design enhances the current density and reduces the pressure drop, resulting in improved fuel cell efficiency.

Secondly, the study investigates the potential of low-weight bipolar plates made with printed circuit boards (PCBs) as the matrix material. Traditional bipolar plates made with graphite or metal are often heavy and bulky, leading to increased material costs and decreased fuel cell efficiency. The use of PCBs as the matrix material results in a significant reduction in weight compared to traditional materials, without sacrificing performance. However, the alkaline environment in fuel cells can cause significant corrosion damage to the bipolar plates over time. To mitigate this issue, the PCBs are coated with a layer of Ni-P electroless coating to protect against corrosion.

Thirdly, the study examines the effectiveness of corrosion protection measures using Ni-P electroless coating. The electroless coating significantly improves the corrosion resistance of the bipolar plates, thereby prolonging their lifespan and maintaining the performance of the fuel cell over time. The combination of low-weight bipolar plates made with PCBs and corrosion protection measures using Ni-P electroless coating has the potential to enhance the overall performance and durability of alkaline PEM fuel cells.

Overall, this study highlights the importance of considering bipolar plate design, material selection, and corrosion protection measures in developing efficient and durable alkaline PEM fuel cells. The optimized flow field design enhances the current density and reduces the pressure drop, while the use of PCBs as the matrix material and Ni-P electroless coating as the corrosion protection measure significantly improve the fuel cell's efficiency and lifespan. These findings provide valuable insights for the development of next-generation fuel cells that are both high-performing and environmentally sustainable.
Comparative Analysis of Degradation of Pristine Nafion and Catalyst Coated Membrane Subjected to Ex-Situ Fenton's Test Approach
Authors: Patra Sudeshna , Trinke Patrick , Bensmann Boris , Hanke-Rauschenbach Richard
Published: February 2024

Polyfluorinated sulfonic –acid ionomer membranes (e.g Nafion) are extensively used today as the benchmark materials for the electrolyte membrane in PEM water electrolysis. It is broadly accepted that the state of the health of PFSA membranes are adversely impacted by the chemical degradation occured during operation of PEMWE. The crossover gases on the catalytic surface generate Hydrogen Peroxide which is homolytically or in the presence of ferrous salts produce reactive oxygen species like hydroperoxyl (HO.) and hydroxyl (HO.) radicals. These radicals attack the ionomer subsequently leading to chain scission, unzipping and loss of functional groups and release of HF in the effluent water.

Other than Fe3+, several transition metal ions Cu2+, Ni2+, Ti3+, Cu+, can poison the membrane significantly. The fact that membrane degradation is accelerated owing to introduction of ferrous ions is fervently implemented in ex-situ degradation tests (known as Fentons tests) to evaluate the durability of membrane materials.

This work depicts a systematic investigation of degradation of pristine Nafion and catalyst coated Nafion membrane using a Fentons accelerated aging experiment. The durability of Nafion 117 and catalyst coated Nafion membrane with various counter ions against H2O2 was explored as a degradation factor of polymer electrolyte water electrolyser. Two distinct variations of the experiments were compared : (1) Nafion and CCM were dipped in only hydrogen peroxide solution, (2) Nafion and CCM were exposed to a solution containing ferrous ions and peroxide. Accelerated aging experiments were conducted over 3-7 days. The difference in degradation phenomena with and without Fe ions were evaluated in terms of the fluoride ion release. For both cases, to quantify the effect of water activity in Nafion and CCM chemical structure on both water diffusion and interfacial transport, pulse field gradient spin echo nuclear magnetic resonance (PFGSE-NMR) technique has been employed. Furthermore the equivalent weight of the Nafion and CCM can vary in presence of aforementioned chemical stressors which can be accurately quantitatively studied by confocal Raman spectroscopy. Morphological characteristic before and after aging test was also investigated. Role of H2O2 and ferous ion in mechanical behaviour of Nafion and CCM were also analyzed. The same experiment was repeated for different transition metal ions. This work sheds light on decomposition mechanism of Nafion and CCM in more detail.
Molecular Additives at the Catalyst Ionomer Interface
Authors: Snyder Joshua David
Published: February 2024

The growth and viability of deep decarbonization through the hydrogen economy is dependent upon scientific advances that will address the existing political, regulatory, and technological barriers that currently hinder electrochemical energy technologies. The strong correlation between device-level performance and catalytic electrode activity/durability highlights the criticality of identifying the limiting processes and developing strategies to address these limitations. The goal of our group is to use fundamental insight derived from the study of well-defined systems to develop unique mitigation strategies, aimed at improving device-level performance, that go beyond simply varying electrocatalyst material properties. The interface between catalyst and ionomer in polymer electrolyte membrane fuel cells (PEMFC) greatly limits device performance through detrimental impacts to local reactant transport and reaction kinetics. Optimization of the catalyst/ionomer interface to not only mitigate these detrimental impacts, but to also beyond existing performance is a challenging task. In this presentation we will present our work in developing molecular interfacial modifying species to optimize the interaction between catalyst and ionomer. Integrating molecular components such as ionic liquids or caffeine both enhances the kinetics of the electrode reactions and limits the detrimental impacts of ionomer on the catalyst surface. We will present our fundamental understanding of why these molecular additives improve catalyst activity and limit the impacts of ionomer. We will also present our integration of these molecular moieties into next generation ionomers and their performance in PEMFC membrane electrode assemblies (MEA).
Highly Durable and Active Electrocatalysts Using Pt Nanorod Catalysts Supported on Nb Doped SnO2 for Polymer Electrolyte Fuel Cells Operating at Wide Temperature Range
Authors: Kakinuma Katsuyoshi , Tano Tetsuro , Shi Guoyu , Uchida Makoto , Iiyama Akihiro
Published: February 2024

The improvement of the durability and activity in cathode catalyst is required toward the wide spread use of polymer electrolyte fuel cells. One of the interesting catalysts is the Pt catalysts supported on SnO2 (Pt/M-SnO2, M = Nb, Ta) without carbon additives [1,2]. The durability (startup/shutdown, load cycling) and oxygen reduction reaction (ORR) activity of the Pt/M-SnO2 is superior to those of commercial Pt catalysts supported on carbon black (Pt/CB) etc. [3-8]. The non-carbon support of M-SnO2 nanoparticles has a unique carbon-like microstructure of a fused-aggregate network structure, which supply the essential function of the electronically constructing pathways via necking of each support particles and the gas diffusion pathways via the open pores surrounded by particles. The Pt nanorod catalyst on M-SnO2 also improves the ORR activity as shown in the catalyst design concept (Fig. 1)[9]. The IV performance of the single cell using the Pt nanorod/Nb-SnO2 cathode catalyst layers at operating temperatures from 80oC to 120oC is quite high to approach the NEDO target performance (Fig. 2) with keeping high durability. The catalyst is considered to have possibilities for application of the heavy-duty vehicles operating at wide-temperature range (< 120oC)[10].

Acknowledgments

This work was partially supported by funds for the project “Electrolytes, Catalysts and Catalyst layers with Extraordinary Efficiency, power and Durability for PEFCs-2030 (ECCEED’30) from the New Energy and Industrial Technology Development Organization (NEDO) of Japan, and JSPS KAKENHI Grant Number (23H02059) from the Ministry of Education, Culture, Sports, Science and Technology.

References

A. Masao, S. Noda, F. Takasaki, K. Ito, K. Sasaki, Electrochem. Solid-State Lett.,12, B119 (2009).

E. Fabbri, A. Rabis, R. Kötz, T.J. Schmidt, Phys. Chem. Chem. Phys., 16, 13672 (2014).

K. Kakinuma, M. Uchida, T. Kamino, H. Uchida, M. Watanabe, Electrochim. Acta, 56, 2881 (2011).

Y. Senoo, K. Kakinuma, M. Uchida, H. Uchida, S. Deki, M. Watanabe, RSC Adv., 6, 321800 (2014).

Y. Chino, K. Taniguchi, Y. Senoo, K. Kakinuma, M. Watanabe, M. Uchida, J. Electrochem. Soc., 162, F736 (2015).

K. Kakinuma, R. Kobayashi, A. Iiyama, M. Uchida, J. Electrochem. Soc., 165, J3083 (2018).

K. Kakinuma, K. Suda, R. Kobayashi, T. Tano, C. Arata, I. Amemiya, S. Watanabe, M. Matsumoto, H. Imai, A. Iiyama, M. Uchida, ACS Appl. Mater. Interfaces
11, 34957 (2019).

K. Kakinuma, M. Hayashi, T. Hashimoto, A. Iiyama, M. Uchida, ACS Appl. Energy Mater., 3, 6922 (2020).

G. Shi, T. Tano, D.A. Tryk, A. Iiyama, M. Uchida, K.Kakinuma, ACS Catal., 11, 5222 (2021).

K. Kakinuma, H. Taniguchi, T. Asakawa, T. Miyao, M. Uchida, Y. Aoki, T. Akiyama, A. Masuda, N. Sato, A. Iiyama J. Electrochem. Soc.
169 (2022) 044522.

Figure 1
From Synthesis to Application: Ni3 Fe N As Oxygen Reduction Electrocatalyst in Anion Exchange Membrane Fuel Cells
Authors: Soto Joesene J. , Abruna Hector
Published: February 2024

Catalysis has played a crucial role in advancing and commercializing energy conversion technologies. It is essential to identify abundant, active, and stable materials to enable the reliable and cost-efficient use of catalysts in renewable technologies such as fuel cells (FCs) and electrolyzers. Suitable candidates, like nonprecious metals, can be found in the transition metals' first row, where materials like bimetallics, metal oxides, and metal nitrides can be obtained. Recently, these materials have shown high activity toward the Oxygen Reduction Reaction (ORR) and the Oxygen Evolution Reaction (OER) in an alkaline medium, which can be related to good performance in FCs and electrolyzers. However, most of the studies do not go further than half-cell reactions. In this study, we explored the synthesis of a metal nitride, Ni3FeN, and its application as a cathode material in hydrogen fuel Anion Exchange Membrane Fuel Cells (AEMFC). A one-step ammonolysis synthesis was done to obtain Ni3FeN supported on carbon. Various metal loadings were synthesized with nanoparticles sizes of 7 ± 2 nm and 10 ± 4 nm for 40% and 60%, respectively, revealed with Transmission Electron Microscopy (TEM). High-resolution Scanning Transmission Electron Microscopy (STEM) images and Energy Dispersive X-ray (EDX) mapping analysis revealed a metal nitride core and a metal oxide shell of ca. 3 nm. The bulk electronic structure was further evaluated using X-ray Absorption Spectroscopy (XAS), where the EXAFS modeling suggests a bulk nitride electronic structure. Consequently, cyclic voltammetry (CV) was used to investigate the electrochemical properties and ORR performance of the Ni3FeN catalyst in 1 M KOH. The catalyst exhibited a stable electrochemical structure with a slight decrease in E1/2 of 10 mV (from 0.85 V to 0.84 V) during a 100 K ORR accelerated durability test (ADT). In addition, Levich and Rotating Ring Disk Electrode (RRDE) analyses showed that the number of electrons transferred during the ORR was consistent with a 4-electron pathway. Furthermore, the Ni3FeN catalyst was tested as the cathode in an AEMFC, obtaining a power density output of 400 mW/cm2, highlighting its potential for alkaline medium fuel cell applications.
One- Step Electrosynthesis of New Catalysts Based on Conjugated Organic Polymers and Copper for Highly Efficient Ethanol Oxidation
Authors: El Rhazi Mama , EL Attar Anas , Bouljoihel Badr , Ezzahi Amine
Published: February 2024

The presence of aromatic compounds rich in carbon and Azote in the backbone of conducting polymers such as polypyrrole, polyaniline, and poly-phenylenediamine improve their capacity to quench metallic particles via amine group to include them into their frameworks. Herein, a new and simple strategy based on electrochemical cascade reactions was used to prepare copper /poly (para-phenylenediamine). The catalysts were prepared by a facile one-pot synthesis via an electrochemical method in a solution containing monomer and copper in a suitable concentration using potentiostatic or galvanostatic mode. Following an in-depth review of the literature, no studies have been devoted to the preparation of catalyst by electrochemical cascade reactions. Herein, Copper oxide/ poly-phenylenediamine has been synthesized in a short time using one single reaction. For this purpose, the synthesis of our electrocatalysts was performed in one step by using one batch containing the para-phenylenediamine, and copper sulfate in the sulfuric acid solution. Two different electrochemical approaches were used for the deposition of our composite. It turns out that using galvanostatic mode leads to the formation of nanodendritic shape of copper in contrast with potentiostatic mode which leads to a spherical form. The response toward ethanol oxidation was greatly affected by the morphology of the obtained nanocomposite. Indeed, the current density obtained when using potentiostatic mode is about 26.55 mA cm-2 at 1.05 V vs Ag/AgCl. This performance is about 2.4 times higher than of the electrocatalyst prepared by galvanostatic mode (11.09 mA cm-2 at 0.85 V). The durability and long-term stability of the obtained electrocatalysts were investigated using chronoamperometry and cyclic voltammetry. The proposed method is highly promising and can provide a route for developing hybrid materials for direct alcohol fuel cell and can be exploited for other applications
Development of a High-Performance Ammonium Formate Fuel Cell
Authors: Pan Zhefei , An Liang
Published: February 2024

Direct liquid fuel cells fueled by molecules such as methanol, ethanol and formate have received many attentions as proton exchange membrane fuel cells, primarily because of its high energy density, simple structure, small fuel cartridge, and ease storage and transport of fuels. Among them, formate, mainly referring to sodium formate or potassium formate, has drawn increasing interest due to the following advantageous characteristics: a high theoretical voltage of 1.45 V, facile and complete formate oxidation in alkaline media, and easy handle in storage and transportation. However, the cation ion (Na+ or K+) in the fuel solution does not contribute to electricity generation but only increase the extra weight load of the fuel cell system, thus lowering the energy density of formate to 2.1 kWh L-1. In this work, ammonium formate is adopted as the fuel, which not only retains the advantages of formate, but also substitutes the Na+/K+ with ammonium (NH4
+) that can be simultaneously oxidized to release electrons, i.e., electricity generation. Hence, the energy density ammonium formate is upgraded to 3.2 kWh L-1. Although promising, the development of ammonium formate fuel cell has been hindered by technical challenges related to the oxidation of ammonium formate, such as sluggish kinetics and electrode degradation. To tackle these issues, a bimetallic Pt-Pd/C electrocatalyst is synthesized by a facial chemical reduction method using sodium borohydride as agent. The Pt-Pd/C electrocatalyst exhibits better electrocatalytic activity for ammonium formate oxidation than pure Pt/C and Pd/C. Then, an ammonium formate fuel cell is developed and tested, which is composed of a Pt-Pd/C anode, a single-atom Fe/C cathode, and an anion exchange membrane (Figure 1). This fuel cell yields an open-circuit voltage (OCV) of 0.88 V and a peak power density (PPD) of 60.7 mW cm-2 at 60oC. When the hydrogen peroxide is used as oxidant, the OCV and PPD are boosted to 1.31 V and 99.6 mW cm-2, respectively. Further increasing the operating temperature to 90oC leads to a PPD of as high as 187.6 mW cm-2. In addition, a mathematical model incorporating mass/charge transport and electrochemical reactions is developed to shed light on the voltage losses and provide guidance for optimizing structural design and operating parameters.

Acknowledgement

This work was supported by a grant the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. N_PolyU559/21) and The Hong Kong Polytechnic University Centrally Funded Postdoctoral Fellowship Scheme (Project No. 1-YXAZ).

Figure 1 Schematic of an ammonium formate fuel cell.

Figure 1
Tungsten Oxide-Based Materials as Catalyst Support for Oxygen Evolution Reaction
Authors: Pan Yung-Tin , Chueh Lu Yu , Hsu Yu-Wei
Published: February 2024

The high cost of iridium (Ir) is a major concern for the large scale deployment of polymer electrolyte membrane water electrolysis (PEMWE). To mitigate its impact, the usage of Ir on the anode must be significantly reduced. Down-sizing the catalyst particle is a straight forward strategy but requires the use of appropriate support materials to disperse and anchor fine Ir nanoparticles. We have investigated the use of tungsten oxide-based materials as support for the oxygen evolution reaction (OER) Ir and ruthenium (Ru) catalyst. The synthesis of nanostructured substoichiometric tungsten oxide and the subsequent loading of ultrafine Ir/Ru-based nanoparticles is thoroughly studied. Due to the successful loading, the mass activity of the tungsten oxide-supported Ir/Ru-based catalyst shows significant improvements under rotating disk electrode (RDE) conditions compared with commercially available Ir/Ru-blacks. Furthermore, non-destructive depth profiling by synchrotron-based X-ray photoelectron spectroscopy (XPS) has revealed the strong catalyst-support interaction which suppressed the oxidation of the supported Ir/Ru-based catalysts, leading to much enhanced durability under accelerated durability testing conditions. To verify its performance under practical PEM electrolysis conditions, the tungsten oxide-supported OER catalyst is directly coated onto a polymer electrolyte membrane, i.e., forming a catalyst coated membrane (CCM), and tested under single cell testing conditions without pressure differential. The voltage dependent chemical state of the supported catalyst is also probed in-situ by synchrotron-based XPS where a potential dependent electron transfer between the catalyst and tungsten-oxide support is discovered. Our discovery is anticipated to aid the development of cost effective PEM electrolysis anodes.
Enhanced Transport in Electrochemical Reactors Using Advanced 3D Printed Electrodes
Authors: Davis Jonathan T. , Seung Kansas , Hammons Joshua Aaron , Ferron Thomas J , Chandrasekaran Swetha , Baker Sarah , Duoss Eric B , Kang Shinyoung , Lin Tiras Y
Published: February 2024

Water electrolyzers employ porous architectures to facilitate the transport of mass and charge. Ensuring effective transport can improve energy efficiency and unlock stable operation at higher current densities. In order to realize these improvements, however, research needs to show the relationship between pore structure and performance. Advances in 3D printing research have enabled the manufacture of functional, electrically conductive porous materials at ever finer length scales and larger build areas. Using electrodes manufactured via projection microstereolithography (PuSL), we first show how this structural control can lead to computationally optimized electrodes which minimize the total power losses of a model single phase reaction. The physics of gas bubble transport in water electrolyzers is more complicated, however. At higher operating current densities, entrained gas bubbles in the triple phase boundary can be a source of degradation by occupying active sites and impeding the flow of ions between electrodes. Using structured pores, controlled surface tension boundaries offer an unprecedented degree of control over gas bubble transport. Integrating these ordered structures into water electrolyzers has the potential to improve the stability of devices at high current densities by guiding bubbles away from the reaction zone and into designed outlets.
Enhanced Hydrogen Evolution Reaction Performance in Alkaline Water Electrolysis: Tuning the 1T Structure of Ni Doped MoS2 Via Co-Sputtering System
Authors: KIM Wan Sik , Sim Junseok , Jung Young HAN , KIM Bonghyun , Tamboli Asiya Mohaseen , Kim Chang-Hee
Published: February 2024

Molybdenum disulfide (MoS2) is a promising catalyst for the hydrogen evolution reaction (HER) in alkaline media due to its low cost and abundance. However, its HER activity is not sufficient for practical application because of its electrochemically inert basal plane and suboptimal hydrogen adsorption energy for HER. Herein, we present a facile synthesis approach to fabricate MoS2/Ni HER electrode with 1T structure using co-sputtering of both MoS2 and Ni. Our results indicated that Ni doping plays a critical role in introducing 1T phase in MoS2 structure, leading to an active basal plan, optimized hydrogen adsorption energy, and strong adhesion between the catalyst film and Ni substrate for highly efficient HER performance and durability. We confirmed that the 1T-phase yield, morphologies, and HER activity are affected by sputtering parameters. Our optimized MoS2/Ni electrode exhibited an overpotential of ~91 mV at 10 mAcm-2 and no significant change in HER performance after 1000 cycles operation in 1 m KOH. Single cell test including our optimized electrode exhibited enhanced overpotential and durability compared to a reference cell, highlighting the potential for commercialization in alkaline water electrolysis industry.
Non-Noble Transition Metal-Based Electrocatalysts for Green Hydrogen Production from Anion Exchange Membrane (AEM) Seawater Electrolyzer
Authors: Selvam Praveen Kumar , Riaz Muhammad Sohail , Farràs Costa Pau
Published: February 2024

As water-scarce is increasing rapidly all over the world, water electrolysis might not be a practical approach for sustainable hydrogen production in the long term. Fortunately, hydrogen production from the anion exchange membrane (AEM) seawater electrolysis enables to achieve of sustainability and durability. But still, suitable electrocatalysts for hydrogen and oxygen evolution reactions in seawater are not figured out yet. Here we report non-noble transition metal-based electrocatalysts for hydrogen and oxygen evolution reaction in seawater electrolysis. The synthesized electrocatalysts were in-situ characterized in X-ray diffraction (XRD), scanning electron microscopy (SEM), Transition electron microscopy (TEM), Raman spectroscopy, and ex-situ characterized in linear sweep voltammetry (LSV), Chronopotentiometry, and impedance studies. Further, the electrocatalysts were investigated in a single-cell anion exchange membrane electrolyzer, and polarization curves, stability tests, and efficiency calculations were carried out. These research findings will be further investigated until attains the industrially required parameters of 1 A cm-2 at a low overpotential of 1.8 V.
PEM Water Electrolyzers: Key Enabler of the Green Energy Transition?
Authors: Carmo Marcelo , Ayers Katherine E.
Published: February 2024

Green hydrogen generation via electrolysis is at the forefront of international debates, with an unprecedent momentum to implement hydrogen production for energy storage purposes. Various countries have already released hydrogen strategy documents, recognizing the high propositional value of hydrogen as the energy commodity of the future.

Commercial polymer electrolyte membrane (PEM) water electrolysis has reached scales of several hundred kg/day, a relevant milestone for industrial scale hydrogen generation using the PEM technology. Nevertheless, the PEM device still poses tremendous potential for continuing cost reduction, leveraging system and manufacturing scaling laws as well as advancements in nanomaterials, advanced manufacturing tools, and a circular economy for all PGM related components.

Significant improvements in some of the highest cost elements have already been achieved, including by NEL Hydrogen. Many of the technology elements such as PFSA membranes, iridium electrodes, porous transport layers, etc. are well stablished, but still need to be refined and validated in a manufacturing environment at scale, including modifications in materials and novel yet economical methods of fabrication.

This talk will describe some of the complex interactions between the elements above. We will include others such as future operating and durability/reliability requirements at scale. Finally, we will attempt to show how next generation PEM technologies will become fundamental for an ultimate energy transition based on hydrogen.
Investigating the Molecular Orientation and Thermal Stability of Spiro-OMeTAD and Its Dopants By Near Edge X-Ray Absorption Fine Structure
Authors: Brady-Boyd Anita , Hazeldine Kerry , Cross Rachel Elizabeth , Ren Gongxizi , Connell Arthur , Kershaw Chris P , Holliman Peter J , Evans David Andrew
Published: February 2024

This work describes the utilization of near edge X-ray absorption fine structure (NEXAFS) to investigate the hole transporting material (HTM) 2,2ʹ,7,7ʹ-tetrakis(N,N-di-p-methoxyphenylamine)- 9,9ʹ-spirobifluorene (Spiro-OMeTAD) and its most common dopants, lithium bis-(trifluoromethylsulfonyl) imide (LiTFSI), 4-tert-butylpiridine (tBP) and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ). Utilizing angle resolved NEXAFS, the orientation of the molecules on the surface can be observed. The data suggests it is difficult to determine any orientational preference for Spiro-OMeTAD deposited on a surface due to the 3D propeller-like geometry of this molecule. Both doped and undoped samples show thermal stability beyond the glass transition temperature of the molecules. Significant changes to the Spiro-OMeTAD spectra were observed with the addition of the dopants, in particular the C K-edge. Differences are also observed in the valence band spectra when dopants are added. It is also demonstrated how the doping combination of LiFTSI with tBP and, F4-TCNQ act as p-type dopants by altering the position of the HOMO levels. The F4-TCNQ induces a larger change in the HOMO levels when compared to the LiTFSI and tBP. These results are important to increase our understanding of Spiro-OMeTAD and the effect dopants have on this material for next generation solar cells.
Understanding Degradation Behavior of Direct-Ammonia Solid Oxide Fuel Cells Using Nanoscale Analyses
Authors: Bagarinao Katherine Develos , Muroyama Hiroki , Matsui Toshiaki , Kishimoto Haruo , Horita Teruhisa
Published: February 2024

Direct-ammonia solid oxide fuel cells (SOFCs) offer a cost-effective and efficient avenue for accelerating the use of hydrogen as a major energy vector. The effect of directly feeding ammonia as a fuel into SOFCs and their associated degradation behavior, however, needs to be fully understood in order to design robust cells capable of operating with good performance and durability at the required high temperatures for extended periods of time. In this study, we performed detailed analyses using advanced techniques such as high-resolution secondary ion mass spectrometry (SIMS) imaging and microscopy methods to examine the microstructural evolution and factors affecting nickel nitriding behavior of model Ni metal surfaces as well as Ni/yttria-stabilized zirconia (YSZ) cermet anodes directly exposed to ammonia as a function of temperature. The results show preferential formation of nickel nitride and presence of OH- species on Ni metal surfaces directly exposed to ammonia, as well as grain boundaries in the bulk which were not directly exposed to ammonia, suggesting enhanced ionic diffusion along these regions. Nickel nitriding is also accompanied by volume expansion which is considered to result in additional mechanical stress. Ni/YSZ cermet anodes, on the other hand, exhibit a significantly higher amount of nickel nitride formed preferentially in pore regions at lower temperatures, suggesting the possibility of nickel nitride decomposition occurring at higher temperatures. The results further suggest a correlation between nickel nitride formation and microstructural features of Ni/YSZ cermet anodes which influence gas diffusion properties. Lastly, a model for the degradation behavior of Ni/YSZ cermet anodes on the basis these results will be proposed and discussed.
Modelling of Ni Nitridation in NH3-Fueled Solid Oxide Fuel Cells
Authors: Chen Ming , Shang Yijing , Chatenet Nestor , Hendriksen Peter Vang , Babaie Rizvandi Omid , Frandsen Henrik Lund
Published: February 2024

In the past decade NH3 fueled solid oxide fuel cells (SOFCs) are getting increasing attention. As compared to hydrogen, ammonia has the advantages of higher energy density and ease of storage and transportation. Due to the high operating temperature of SOFCs, typically in the range of 550-750C, NH3 can be easily decomposed into nitrogen and hydrogen over Ni-based cermet fuel electrodes. Previous studies have demonstrated NH3-fueled SOFCs with high power density, high efficiency and low emissions. One of the remaining challenges is the nitridation of Ni electrode. Under realistic operating conditions, Ni in the support and active layers of the fuel electrode has a tendency of being nitride when exposed to NH3, forming Ni3N and resulting in performance degradation. In this work, the thermodynamics of the Ni-N system is explored using the CALculation of PHAse Diagrams (CALPHAD) method. The kinetics of Ni3N formation in NH3-fuelled SOFCs is then predicted, taking into account the kinetics of both ammonia decomposition and Ni3N formation. The locations inside NH3-fuled SOFCs with potential risks of Ni nitridation are then predicted and strategies to avoid or reduce nitridation are further proposed.
(Invited) From Electronic Conductivity Measurement to Its Role on Oxygen Electrode Delamination Phenomena: A Brief Review
Authors: Zhu Liangzhu
Published: February 2024

Over the past few decades, degradation and stability of SOEC has been a major concern for long term applications. Numerous factors such as cell fabrication, materials selection including both cell components and metallic interconnects, operation voltage and current density, working temperatures, gas compositions, stacking techniques, etc., can all affect the stability. While seemingly it is challenging to separately identify and determine the contribution of each factor, delamination of oxygen electrode was reported as one of the main reasons for this degradation or failure [1-3]. Theoretical analyses, particularly by Anil Virkar, have shown that the actual oxygen chemical potential inside the electrolyte can be well above or below the corresponding values at the two electrodes in a SOEC when using predominantly oxygen ionic conducting membranes, leading to either delamination at oxygen electrode or electro-reduction near the fuel electrode [4-6]. Therefore, it is critical to measure electronic conductivity in the electrolytes.

Meanwhile measurement of electronic conductivity in MIEC is typically done by the classical Hebb-Wagner (H-W) polarization method[7, 8]. Over the past decades, it has been realized that the H-W method has some critical limitations or issues that may limit its accuracy or testing feasibility, such as relatively long relaxation time towards steady state, challenges on sealing, violation of true ionic blocking and possible interaction with gas phases. A few modified versions of H-W techniques and also non-H-W type techniques on electronic conductivity measurement have been reported and investigated[9-12] . In this report, a brief review is given to cover both of these topics.

References

[1] J.E. O'Brien, J.S. Herring, C.M. Stoots, G.L. Hawkes, J.J. Hartvigsen, M. Shahnam, International Journal of Hydrogen Energy, 32 (2007) 440-450.

[2] M.A. Laguna-Bercero, R. Campana, A. Larrea, J.A. Kilner, V.M. Orera, Journal of Power Sources, 196 (2011) 8942-8947.

[3] C. Graves, S.D. Ebbesen, M. Mogensen, Solid State Ionics, 192 (2011) 398-403.

[4] A.V. Virkar, Journal of Power Sources, 147 (2005) 8-31.

[5] A.V. Virkar, International Journal of Hydrogen Energy, 35 (2010) 9527-9543.

[6] A.V. Virkar, G. Tao, International Journal of Hydrogen Energy, 40 (2015) 5561-5577.

[7] M.H. Hebb, The Journal of Chemical Physics, 20 (1952) 185-185.

[8] C. Wagner, in: 7th International Conference Electrochem. Thermodyn. Kinetics, Lindau, 1955, pp. 361.

[9] X. Guo, J. Maier, Solid State Ionics, 130 (2000) 267-280.

[10] C. Chatzichristodoulou, P.V. Hendriksen, Physical Chemistry Chemical Physics, 13 (2011) 21558-21572.

[11] L. Zhu, L. Zhang, A.V. Virkar, Journal of The Electrochemical Society, 162 (2015) F298-F309.

[12] L. Zhang, L. Zhu, A.V. Virkar, Journal of Power Sources, 302 (2016) 98-106.
(Invited) Utilization of Bio-CO2 and Bio-Methane for Fuel Production: Integration Solid Oxide Electrolyzer, Low Energy Plasma Reformer with Fischer-Tropsch Synthesis
Authors: Elangovan S , Hartvigsen Joseph , Hollist Michele , Elwell Jessica
Published: February 2024

Transition to renewable energy is essential to achieve climate protection objectives. Besides storing electricity for later use, fuel production using renewable energy is an essential part of reducing fossil dependance. Hydrogen production is receiving the greatest attention as a carbon free energy carrier with the potential to fuel future fleets of hydrogen fuel cell vehicles, to store grid electricity to accommodate asynchronous generation and load, and to a lesser extent to displace heating fuels. However, the highest value application in current markets is the production of liquid transportation fuels such as sustainable aviation fuels (SAF) and low (fossil) carbon diesel fuel. However, liquid hydrocarbon fuels only achieve the decarbonization goals if they displace fossil fuels and are produced from sustainable, ideally biogenic carbon resources.

Solid oxide electrolysis cell (SOEC) stack developed by OxEon team for MOXIE, the Mars OXygen ISRU Experiment has demonstrated the use of CO2 as an electrolysis feedstock aboard the Perseverance rover which as of this writing has operated thirteen times on Mars, splitting the Mars atmosphere CO2 to carbon monoxide and oxygen, as the first ever demonstration of In Situ Resource Utilization (ISRU) on another planet. The technology is applicable to efficient resource utilization on this world and OxEon is actively developing power to fuels technology to maximize the conversion of biogenic carbon to high value, energy dense, liquid transportation fuels that are needed by an existing vehicle fleet that will be on the road and in the air decades to come.

OxEon’s technologies are being applied to bridge the electrical and materials energy sectors. In this project OxEon processes the bio-CO2 through an SOEC and the bio-CH4 through a low energy plasma reformer. The combined synthesis gas is supplied to a Fischer-Tropsch reactor. The combination offers several advantages: the yield of biofuel nearly doubles by use of the bio-CO2 compared to the bio-methane alone, cooling the FT reactor generates all the steam needed in the SOEC system reducing the effective operating voltage (accounting for raising steam) from > 1.5 V/cell to < 1.3 V/cell, oxygen by-product from the SOEC is used in the autothermal reformer, as is some of the FT produced water. The product fuel is all bio-carbon, but it also embodies renewable electric energy in a high-value, storable and transportable liquid hydrocarbon that will be usable in the current air and ground fleets.
Phase-Field Modelling of Microstructure Evolution in Solid Oxide Cells
Authors: Shang Yijing , Chen Ming
Published: February 2024

Solid Oxide Cell (SOC) is one of the most promising energy conversion devices due to its high efficiency, flexible fuel adaptability, and low pollutant emission. By changing the operation condition, the SOC can be operated as a solid oxide fuel cell (SOFC) to convert chemical energy to electricity or as a solid oxide electrolysis cell (SOEC) to store electricity in the way of chemical energy. However, the performance degradation of SOCs caused by microstructure evolution and phase transition during long-term operation, and the stress-induced structure damage limit the SOC’s lifetime. This is one of the most challenging problems to be tackled on the way to commercialize the SOC technology. To clarify degradation mechanisms and develop counter-acting measures, long-term testing combined with detailed post-mortem characterization is one common approach, but this is often associated with extensive amount of experimental work and long research time and thus very costly. Instead, many researchers have devoted their efforts to investigating the degradation phenomena using computational modelling or simulations. Phase field model, which has been widely employed to study microstructure evolution of alloy materials during solidification, aging etc., has also been utilized in the SOC research, to illustrate the microstructure evolution during long-term operation from micron to millimeter scale, with the possibility of taking into account the mechanical properties as well. In this article, the principle of the phase field method and different models are introduced first, following with detailed examples published in literature on phase field modeling of various (degradation) phenomena in SOCs. Finally, possible strategies coupling modelling and experimental research in optimizing SOC performance and microstructure is discussed.
Approaches to Reduce the Operating Temperature of Protonic Ceramic Electrochemical Cells to <450°C
Authors: Liu Fan , Fang Liyang , Duan Chuancheng
Published: February 2024

Protonic ceramic electrochemical cells (PCECs) have been developed as a promising technology for efficient power generation and hydrogen production via steam electrolysis. However, the current operating temperature range of 450-600°C still limits their widespread application and adoption in ceramic electrochemical cell technology. To address this issue, lowering the operating temperature range to 250-450°C has been proposed, which would expand the range of materials for building PCEC systems and reduce their cost. In this presentation, I will discuss our group's series of approaches to redesign PCECs. These approaches include using readily fabricated single-grain thick, chemically homogeneous, and robust electrolytes, as well as newly developed positive electrode materials. Our innovations have simultaneously reduced the electrolyte ohmic resistance, electrolyte-positive electrode contact resistance, and electrode polarization resistance, while also improving durability. As a result, we have set several new records of using PCECs for both power generation and renewable hydrogen production.
Highly Conducting Sc and Y co-doped Zirconia Solid Electrolyte Thin Films Prepared via Pulsed Laser Deposition for Solid Oxide Electrochemical Cells Applications
Authors: Rabo Jennet , Tsuchiya Takashi , Terabe Kazuya , Cervera Rinlee Butch
Published: February 2024

Scandium (Sc) and yttrium (Y) co-doped ZrO2 thin films were fabricated via pulsed laser deposition (PLD). The target material, 4 mol% Sc2O3 and 4 mol% Y2O3 co-doped ZrO2 (ScYSZ), was first synthesized via a solid-state reaction. The ScYSZ thin film was deposited on SiO2-Si substrate by laser ablation, using a Q-switched Nd3+:YAG laser (λ = 266 nm) and substrate temperatures of 600 and 800 oC. Micro-structural and conductivity properties of the resulting as-deposited thin films were investigated. X-ray diffraction (XRD) sample patterns revealed that the as-deposited polycrystalline films can be indexed to a cubic structure. In addition, varying the oxygen partial pressures during the deposition was studied. FE-SEM images revealed dense and crack-free surface morphologies achieved at lower oxygen partial pressures (0.01 Pa and 0.1 Pa) and rough surface with porous morphology at high oxygen partial pressures (1.0 Pa and 10 Pa). The thickness of the film is about 120 nm for the thin film deposited at 800 oC substrate temperature (TS). The total conductivity of the thin film was measured using electrochemical impedance spectroscopy (EIS). Interestingly, the calculated total conductivity of the deposited ScYSZ thin film, 0.1 Pa and TS at 800 oC, revealed about 2.8x10-1 S/cmat 700 oC and with activation energy (Ea) of 0.78 eV from 500 oC to 700 oC. The fabricated as-deposited ScYSZ thin film is one of the highest reported highly conducting solid electrolytes that is a promising material for fuel cell or electrolysis cell applications.