bluuebunny/crossref_metadata_2025 huggingface dataset:
(Digital Presentation) Physical and Chemical Properties of Lithium Tetrachloroaluminate Monosolvate with Sulfur Dioxide
Authors: Garipov Dmitriy , Kuzmina Elena , Golubyatnikova Ludmila , Mishinkin Vadim , Kolosnitsyn Vladimir
Published: August 2024

In connection with the expansion of the areas of application of lithium-ion batteries and the increase in their energy characteristics, researchers are increasingly paying attention to the problems of battery safety. The use of non-flammable electrolyte systems will significantly improve the safety of lithium-ion batteries.

Electrolyte systems based on solvate complexes of sulfur dioxide have high electrical conductivity and are non-flammable [1]. The most studied composition is LiAlCl4 × 1.6 SO2 [1] and LiAlCl4 × 3 SO2 [2]. The properties of LiAlCl4 x SO2 monosolvate have not been described in the literature.

The presented work summarizes the results of studies of the physicochemical properties (electrical conductivity, viscosity, density) of lithium tetrachloroaluminate monosolvate with sulfur dioxide (table). The temperature dependences of viscosity, density and electrical conductivity are presented in the figure.

This work was performed as part of the Ministry of Science and Higher Education of the Russian Federation [Government Order Theme No. 121111900148-3].

References

Hartl, R., Fleischmann, M., Gschwind, R., Winter, M., & Gores, H. (2013). A Liquid Inorganic Electrolyte Showing an Unusually High Lithium-Ion Transference Number: A Concentrated Solution of LiAlCl4 in Sulfur Dioxide. Energies, 6(9), 4448–4464. DOI:10.3390/en6094448

Chul Wan Park, & Oh, S. M. (1997). Performances of Li/LixCoO2 cells in LiAlCl4 · 3SO2 electrolyte. Journal of Power Sources, 68(2), 338–343. DOI:10.1016/s0378-7753(97)02518-4

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Scaling Considerations for the Commercialization of the Electrochemical CO2 Reduction Reaction
Authors: Rawls Brian , van den Bosch Bart , Krasovic Julia , Jongerius Annelie
Published: August 2024

The Electrochemical CO2 Reduction Reaction (ECO2RR) is an attractive method to produce CO2-based chemicals. Formate is an ideal target compound due to its high atom efficiency, low electrical demand, and potential as a building block for carbon-negative products. In recent years, low temperature ECO2RR electrocatalyst research has developed rapidly, reporting impressive efficiencies (>90 % FE) at industrial relevant current densities (>200 mA/cm2). While these are essential metrics, there is less focus on the commercialization of these systems, such as electrode stability and process scalability. For industrial feasibility, ECO2RR electrolyzers must be >1 meter high, stable for 5 years, and operate under elevated temperatures and fluctuating pressures. This presents challenges to typical gas diffusion electrodes used in ECO2RR, which rely on a fine pressure gradients for efficient gas transport to the catalyst layer. Furthermore, high product concentrations and high CO2 utilization are essential for achieving an overall, energy efficient process. At Avantium’s Volta group, we industrialize ECO2RR processes. This presentation will demonstrate the scaling potential of these processes with examples from our pre-pilot units. Overall, we believe that ECO2RR will be a key technology to de-fossilize the chemical industry and valorize CO2 as the feedstock of the future.

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Manufacture of the Invar Film Using a Continuous Electrodeposition Technique for the OLED FMM
Authors: KIM In Gyeong , Lee Jun Ha , Kim Jin-Bum , Shin Se Eun , Park Yong Bum
Published: August 2024

In the manufacturing processes of red-green-blue (RGB)-type organic light emitting diode (OLED) displays, Invar is used as a material for the fine metal mask (FMM), which guides the evaporated diode materials through its small holes onto the correct positions of the substrate glass. The electroforming of Invar is an immediate hot issue in the RGB-type OLED display industries. Contrary to the conventional top-down method of pyrometallurgically producing Invar, a bottom-up approach of electroforming is a promising technology for producing very thin FMMs to achieve high-quality images in such displays. The present authors have recently presented that the electroformed Invar via sophisticated heat treatment exhibits the coefficient of thermal expansion (CTE) as low as that of the conventional Invar. The current work has been aimed at investigating the effect of the microstructure evolution on the CTE during heat treatment of the electroformed Invar. Finally, we propose optimal process conditions to manufacture the Invar FMM applied for an ultra high definition (UHD) grade of the OLED display.
(Invited) Electrolysis of Liquid Dairy Cow Manure into Clean Reusable Water
Authors: Bailey Shorma Bianca
Published: August 2024

Livestock wastewater management is a critical concern in the United States, with an annual production of 1.2 to 1.37 billion tons of waste, surpassing human waste by three to twenty times. This mismanagement poses significant threats to freshwater sources, ecosystems, and public health. Agriwater’s project proposes an innovative solution using electrocoagulation (EC) treatment. The EC technique is a process involving the intentional corrosion of aluminum or iron electrodes to introduce trivalent ions, facilitating the co-precipitation and coagulation of contaminants, making their removal as sludge easier. The project's primary objective is to use electrolysis to convert liquid animal waste into clean water for irrigation, drinking, and farm maintenance. This solution is vital for various farms, including those facing drought, zero-discharge, and EPA-permitted farms discharging manure into rivers. Preliminary research shows EC's potential to significantly reduce turbidity and phosphate levels in livestock wastewater, forming the basis for scalable on-site treatment. The project team, with expertise in electrolysis, wastewater treatment, and agricultural engineering, ensures the development of an industrial-grade water treatment system. This project is in collaboration with Oak Ridge National Laboratory and the University of Tennessee's Dairy Farm and addresses immediate environmental challenges that contribute to a more sustainable and responsible agricultural industry.
(Invited) Electrolysis for Sustainable Ethylene at Dioxycle
Authors: Li Chastity
Published: August 2024

Industrial emitters are responsible for more than a third of global emissions. The central mission at Dioxycle is to divert industrial carbon emissions from entering the atmosphere and instead transform them into ethylene. Ethylene has a growing annual demand currently in excess of 150 Mton globally, corresponding to a $170 bn market, and is used in a wide range of consumer goods including fabrics, plastics, and construction materials.

Electrified chemical manufacturing is a natural choice for generating sustainable products, but the biggest challenges to its widespread adoption include scalability of production and cost competitivity with fossil-based alternatives. A key difference between academia and industry is the critical focus on the factors that most directly influence the cost of the ultimate product. For electrified chemical manufacturing, this translates to voltage and long-term stability. For example, in a two-electron process such as water electrolysis, an overpotential of 1 V (total voltage 2.23 V) adds an additional 26.6 kWh or roughly $4 to the price of H2 per kg. For comparison, nonrenewable H2 produced from steam methane reforming can be sold for $1/kg H2. Additionally, electrochemical production must scale rapidly to meaningfully compete with their fossil-based alternatives. For a startup in particular, development and research targets must always have these considerations at the forefront and be able to adapt quickly to the latest results. While there are many challenges ahead, the growth of this field and the partnerships between academia and industry will be crucial to achieving our climate goals.
(Invited) CO2-Negative Ethylene Via Electrolysis – Greenerene™, a Green Chemistry Start-up
Authors: Lattimer Judith , Zhang Tianyu , Belt Andy
Published: August 2024

Reduction of greenhouse gases is vital for the long-term environmental health of the planet. While there has been progress in reducing and capturing CO2 emissions, a vast majority of emissions are not captured, and atmospheric CO2 concentration continues to rise. This creates a large and growing market for CO2 sequestration and utilization, which presents an opportunity to rethink how commodity chemicals, which often come with a large carbon footprint, are produced in the US and globally. C2H4 is a key building block in the chemical industry to produce a wide range of plastics, solvents, cosmetics, etc. On average, the production of 1 MMT of C2H4 generates 1.5 MMT of CO2, from fuel combustion, decoking, and utilities. Globally, C2H4 production by steam cracking is ranked as the second-largest contributor of energy consumption (2.8 EJ/year) and greenhouse gas emissions (300 MMT of CO2-e/year) in the chemical industry. Electrochemical CO2 reduction reaction (CO2RR) to produce C2H4 at ambient conditions, when coupled with renewable electricity, could reduce dependence on fossil fuels and decarbonize the chemical sector associated with C2H4 production.

At Giner, we are developing technology to improve selectivity, productivity, and durability of the CO2 electrolyzer, enabling commercial deployment. This technology is the basis of a spin-out start-up company called Greenerene™ that is currently seeking investment funding to scale up to the pilot plant scale over the next 3-5 years. Currently, our state-of-the-art electrolyzer has achieved 60% C2H4 selectivity at 500 mA cm-2 and 3 V in a 50 cm2 MEA electrolyzer. We are in the process of translating this performance into multi-cell stacks and larger-area cells to enable 1-ton/day production of ethylene at the pilot scale.

We have also developed a detailed Techno-Economic Analysis of our technology, including cost of carbon capture, renewable electricity, and balance of plant including power electronics, recirculation, and purification systems, that demonstrates a pathway to economic competitiveness. With the addition of already implemented and anticipated carbon credits, at scale our technology should be able to produce ethylene at less than current market prices, and with significant environmental and climate benefits compared with current production methods.

Acknowledgement: The project is financially supported by the Department of Energy’s Office of EERE under Grants DE-EE000942l and DE-EE0010836.
(Invited) EDAC Labs: Carbon Removal via Acid-Base Electrochemistry
Authors: Shen Hao
Published: August 2024

EDAC Labs(https://edaclabs.com/) uses the electrochemical production of acid and base to decarbonize the world through conventional direct air capture, enabling carbon-negative mining, and by providing technology for other applications such as direct ocean capture, ocean alkalinity enhancement, and enhanced weathering. EDAC Labs’ electrosynthesizer device creates acid and base at reduced energy cost of conventional processes. For conventional direct air capture developers, EDAC Labs provides technology that is low cost and operates at ambient temperature and pressure. For direct ocean capture and ocean alkalinity enhancement developers, EDAC Labs supplies electrochemistry solutions to developers that lower project costs. For metal mines, EDAC Labs provides technology that extracts valuable metals while sequestering carbon to achieve carbon-negative mining. The acid is used to start the recovery of valuable metals from mine tailings, and the base is used to capture CO2 from air. The acid and base streams are then combined to extract metals that can be sold for applications such as batteries, and to create solid carbonates, which permanently store CO2.

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Enhanced Mechanical Properties with Ag Addition in Electroplated Ni-Sn Solder Joints: Sub-10 Micron Bond Thickness
Authors: Li Yi-Chen , Lee Yin-Ku , Duh Jenq-Gong
Published: August 2024

Keywords: Micro-bump; Microstructure; Intermetallic compounds; Mechanical properties; thermocompression bonding

The advancement of electronic devices has garnered more extensive attention towards three-dimensional integrated circuit (3D-IC) technology due to microbump size reduction and increased power density. Microbumps play an important role in driving the development of this technology, especially in 3D chip-stacking involving multiple reflow processes. The reduction in microbump height spotlights the presence of intermetallic compounds (IMCs). In comparison to traditional ball grid array (BGA) solder joints, microbumps with smaller solder volumes exhibit a predominant fraction of IMCs at solder joints, especially with microbump dimensions potentially shrinking to less than 10 micrometers.

The interface reaction within confined spaces has become a critical concern. Mechanical properties will be dominated by IMC properties rather than solder characteristics. In conventional Cu/Sn/Cu solder joints, grain coarsening and prolonged reflowing times, which result in IMC collisions from opposing substrates, forming columnar grains with a uniform orientation, make the solder joint less reliable. Furthermore, the Cu3Sn layer in Cu/Sn/Cu microbumps presents another challenges, indicating the formation of Kirkendall voids, increasing the risk of brittle interface fractures.

This study investigates the mechanical reliability and microstructure of two sub-10um sandwiched structures: Cu/Ni/Sn/Ni/Cu and Cu/Ni/Sn-3.5Ag/Ni/Cu. In the 3D-IC manufacturing process, solder joints will experience multiple reflow processing. Different reflow heat treatment process to achieve different fractions of Ni3Sn4 IMCs were performed on both sandwiched structure. Despite the formation of internal voids due to volume shrinkage in Ni/Sn solder joints, the addition of silver in the solder, forming Ag3Sn, effectively fills these voids. The long-time reflowed sample showed outstanding mechanical properties via the addition of silver in solder. In this study, the influence of silver addition on the microstructure and mechanical properties of the overall joints under identical reflow conditions, the fracture path observation after shear test were investigated. The growth mechanism of Ag3Sn and its distribution in the solder would be further explored and addressed.

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Deposition Kinetics and Characteristics of Peald Igzo Films Using Tetrahydrofuran-Adducted in & Ga Precursors
Authors: Lee Samdong , Jeon Sang-Yong , Lee Gyun-Sang , Kwone Yong-Hee , Im Young-Jae , Byun Tae-Seok , Lee Sang-Ick
Published: August 2024

As the down-scaling of semiconductor materials, silicon compatible emerging materials have extensively researched for next generation display and 3D structured devices. In particular, oxide semiconductors are considered a promising candidate for backplane applications in display. Among them, indium-gallium-zinc oxide (IGZO) using plasma enhanced atomic layer deposition (PEALD) has excellent properties, like high mobility, low leakage current, high transparecy and low temperature processablility. However, conventional precursors for IGZO still have some prolems to solve such as low deposition rate, low thermal stability and high price.

In this study, we developed indium precursor (Trimethylindium Tetrahydrofuran, DIP-4) and gallium precursor (Trimethylgallium Tetrahydrofuran, DGP-2) to overcome the shortcomings of the conventional In & Ga precursors. ALD characteristics of the films deposited using the newly developed the precursors were confirmed through the source feeding time saturation and linearity. Furthermore, the incubation time of In, Ga and Zn oxide films according to the different bottom layer was respectively verified and calculated using the developed DIP-4, DGP-2 and commercially used DEZn. In order form a multilayer IGZO thin film, application of the incubation factors at IGZO process were experimentally demonstrated. Thickness of the IGZO films can be easily controlled through modulation of the incubation factors. The physical and chemical properties of the films were analyzed by X-ray diffraction, X-ray reflectrometer, X-ray photoelectron spectroscopy, transmission electron microscope.

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Etch Characteristics of Cobalt Thin Films in High Density Plasma of Cl2/O2/Ar Gas Mixture
Authors: Oh Kyung Ho , Baek Geum Bin , Cho Yoon Jae , Ha Su Myung , Chung Chee Won
Published: August 2024

Inductively coupled plasma reaction ion etching (ICP-RIE) of cobalt thin films patterned with SiO2 hard masks was performed using Cl2/O2/Ar gas mixture. The etch characteristics of cobalt films in Cl2/Ar gas were examined to determine the roles of Cl2 and O2, respectively. The etch rates and etch profiles of cobalt films were investigated by varying the O2 concentration in Cl2/O2/Ar gas mixture.

In the optimized Cl2/Ar gas mixture, systematic etching of cobalt films was performed by changing the etch parameters including ICP RF power, DC-bias voltage, and process pressure. As the DC-bias voltage and process pressure was increased, the etch rate increased and the etch profile improved. Through the etching parameters variation experiment, the etching properties were investigated by adding O2 to Cl2/Ar under optimized conditions. X-ray photoelectron spectroscopy and optical emission spectroscopy were used to investigate the etch mechanism in the Cl2/O2/Ar gas mixture. In addition, scanning probe microscope was used to observe roughness on the etched cobalt surface. Finally, the etching of cobalt films patterned with nanometer-scale in the optimized Cl2/O2/Ar gas mixture was successfully achieved with good etch profile.

Acknowledgment

This research was supported by the Ministry of Trade, Industry & Energy (MOTIE) (20019504) and Korea Semiconductor Research Consortium (KSRC) support program for the development of future semiconductor devices. This work was supported by Korea Institute for Advancement of Technology (KIAT) grant funded by the Korea Government (MOTIE) (P0008458, HRD Program for Industrial Innovation).
New Hybrid Materials Based on N-Doping Copolymers of Thiophene Derivatives for Electrochemical Energy Storage
Authors: Sadki Said , Gentile Pascal , Marechal Manuel
Published: August 2024

Over the past decade, electroactive conducting polymers (ECPs) are among the most potential pseudocapacitive materials for the electrodes of microsupercapacitors. ECPs exhibit several advantages, such as good conductivity (up to 103 S cm-1), flexibility, high specific capacitance (values ranging from 300 to 800 F.g-1 depending on synthesis and electrochemical performance conditions), relatively cheap and ease of synthesis [4]. Therefore, the electrochemical deposition of ECPs revealed a new strategy to design a great variety of various polymer morphologies as an innovative pseudocapacitive materials. Based on the different storage mechanism, electrochemical supercapacitors can be divided into three types, namely electrochemical double layer capacitors (EDLCs), pseudosupercapacitors and hybrid supercapacitors in which ECPs and other pseudocapacitive materials such as carbon materials, transition metal oxides, nitride complexes allow to store higher amount of capacitance per gram (faradic reactions) than EDLCs (pure capacitive energy storage reaction).

In this work, we have elaborated new n-doped conducting polymers Poly[3,6-bis(2-thienyl)pyridazine] and Poly[3,6-bis(2-(3-n-hexylthienyl))pyridazine] by making electropolymerization on Pt disk electrode and 3 nm alumina coated silicon nanowires in acetonitrile organic electrolyte. The comonomers 3,6-bis(thienyl)pyridazine and (3,6-bis(2-(3-nhexylthienyl))pyridazine) have been successively synthesized. The produced polymeric materials Poly[3,6-bis(2-thienyl)pyridazine] and Poly[3,6-bis(2-(3-n-hexylthienyl))pyridazine] during n-doping process on Pt working electrode in acetonitrile solution of TBAPF6 (0.1 M) expose very low potential value of -2.23 V and -2.19 V at current density of -0.25 mA.cm-2 and -0.06 mA.cm-2, respectively. The elctropolymerization of synthesized comonomer 3,6-bis(thienyl)pyridazine has been done on Al2O3@SiNWs and resulted in thin layer of polymer film with micropores. The experimental results are compared to electropolymerization study of thiophene monomer on Pt disk and Al2O3@SiNWs electrodes to highlight the similarities and electrochemical advancements.
(Electronics and Photonics Division Poster Award Winner) Operation up to 225°C of NiO/ β-(Al0.21Ga0.79)2O3 /Ga2O3 Heterojunction Lateral Rectifiers
Authors: Wan Hsiao-Hsuan , Li Jian-Sian , Chiang Chao-Ching , Xia Xinyi , Ren Fan , Masten Hannah , Lundh James Spencer , Spencer Joseph , Alema Fikadu , Osinsky Andrei , Jacobs Alan G. , Hobart Karl D. , Tadjer Marko , Pearton Stephen J
Published: August 2024

The characteristics of NiO/β-(Al0.21Ga0.79)2O3/Ga2O3 heterojunction lateral geometry rectifiers with the epitaxial layers grown by metal organic chemical vapor deposition were measured over a temperature range from 25 °C–225 °C. The forward current increased with temperature, while the on-state resistance decreased from 360 Ω.cm2 at 25 °C to 30 Ω•cm2 at 225 °C. The forward turn-on voltage was reduced from 4 V at 25 °C to 1.9 V at 225 °C. The reverse breakdown voltage at room temperature was ∼4.2 kV, with a temperature coefficient of −16.5 V•K−1. This negative temperature coefficient precludes avalanche being the breakdown mechanism and indicates that defects still dominate the reverse conduction characteristics. The corresponding power figures-of-merit were 0.27–0.49 MW•cm−2. The maximum on/off ratios improved with temperature from 2105 at 25 °C to 3 × 107 at 225 °C when switching from 5 V forward to 0 V. The high temperature performance of the NiO/β-(Al0.21Ga0.79)2O3/Ga2O3 lateral rectifiers is promising if the current rate of optimization continues.
Breakdown up to 12 Kv in NiO/β-Ga2O3 Vertical Heterojunction Rectifiers
Authors: Li Jian-Sian , Wan Hsiao-Hsuan , Chiang Chao-Ching , Yoo Timothy Jinsoo , Ren Fan , Kim Honggyu , Pearton Stephen J
Published: August 2024

Vertical heterojunction NiO/β n-Ga2O/n+ Ga2O3 rectifiers fabricated on 15 µm thick drift layers with carrier concentration 8.8 x1015 cm-3
and employing simple dual-layer PECVD SiNx/SiO2 edge termination demonstrate breakdown voltages (VB) up to 12 kV, on-voltage (VON) of ~2.2V and on-state resistance RON of 11.1-12 mΩ.cm2
. The breakdown field is ~8 MV. cm-1, close to the commonly accepted theoretical value. The associated power figure-of-merit, VB
2/RON is 13 GW·cm-2
. By sharp contrast, Schottky rectifiers concurrently fabricated on the same drift layers had maximum VB of 2.9 kV, but lower VON of 0.71-0.75 V. Transmission electron microscopy showed an absence of lattice damage between the PECVD and sputtered films within the device and the underlying epitaxial Ga2O3. The key advances are thicker, lower doped drift layers and optimization of edge termination design and deposition processes.

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Gas Sensing of Chemical Vapor Deposition-Formed Zinc-Doped Indium Oxide Nanowires
Authors: Yu Che-Wen , Fu Hsuan-Wei , Yang Shu-Meng , Lin Yu-Shan , Lu Kuo-Chang
Published: August 2024

Although indium oxide has been extensively utilized for gas detection of pollutants, it is still possible to further improve the gas sensitivity and selectivity. Here, we fabricated zinc-doped indium oxide nanowires of excellent morphologies and high crystallinity via chemical vapor deposition. Electrical measurements by a single-nanowire microdevice reveal that doping of zinc contributed to the increasing electrical resistivity; as an acceptor, the lower valence of the dopant caused the decreasing electrical conductivity. X-ray photoelectron spectroscopy analysis demonstrates the increasing oxygen vacancies from appropriate doping, changing oxygen adsorption on the nanowires, which led to enhanced gas sensing properties. Reducing gases, including carbon monoxide, acetone, and ethanol, were utilized to judge the sensing ability. It turns out that the response of the doped nanowires was higher than that of undoped ones at 5 ppm and low temperatures; the gas sensing response of zinc-doped In2O3 nanowires was 13 times higher than that of undoped In2O3 nanowires at 300°C. Consequently, higher zinc doping concentration in In2O3 nanowires enhanced gas sensing performance with increasing oxygen vacancies from doping and improving gas molecule adsorption. Zinc-doped In2O3 nanowires can be attractive choices for environmental detection and life science.
Emerging Bismuth-Based Materials: From Fundamentals to Energy Applications
Authors: El-Shazly Ayat
Published: August 2024

In practical applications, supercapacitors, renewable and efficient techniques of energy storage and conversion, are commonly assembled into supercapacitor, which has been attracting growing interest in energy applications for the past decade. To achieve this decisive task, it is essential that electrode materials with high energy density and electrochemical stability are explored for environment-friendly and economical utilization. Numerous studies have been conducted on metal-based compounds and their relative materials; including bismuth-based materials and their composites are promising because of their redox behavior, charge storage capacity, environmental friendliness, and increasing research toward their application in energy for solar water splitting and supercapacitor. Herein, we outline bismuth materials and their composites, as investigated by our research, highlight their applications in energy, and, more importantly, focus on the study of their performance in photoelectrochemical hydrogen production and supercapacitive electrochemical techniques. We also present a summary of energy storage devices and their mechanisms, as well as other types of non-bismuth-based electrode materials available in the market. In addition, the major challenges and future perspectives of bismuth-based composites for energy purposes are addressed.
(Invited) Contact-Free, Wireless Wearable Physiological Sensors Based on Plasmonic Metamaterials
Authors: Wu Changsheng
Published: August 2024

Wearable sensors offer a promising avenue for tracking disease progression and delivering care outside traditional clinical settings. However, existing wearable sensors require strongly adherent interfaces to the skin for continuous physiological monitoring. In this work, we propose a novel approach that introduces compact, flexible, wireless sensors capable of continuous physiological signal monitoring without the need for direct skin contact. Our sensing device integrates a wireless sensing component, a 24-GHz transceiver, and a microcontroller unit on a flexible printed circuit board. The wireless sensing mechanism allows these sensors to be placed without any physical contact to the body, including on eyewear, clothing, and wristbands. Experimental results demonstrate the effectiveness of these non-contact sensors in accurately monitoring vital signs, including heartbeat, respiration, wrist pulse, and temporal pulse.
(Invited) 3D Printing for Tissue Scaffolds with Tunable Mechanical Durability and Sensing Capabilities
Authors: Song Kenan , Zhu Yuxiang , Thummalapali Sri Vaishnavi , Fonseca Nathan
Published: August 2024

Pelvic organ prolapse (POP) is a prevalent condition among senior women, characterized by the descent or herniation of pelvic organs into the vaginal canal. It is a widespread issue, affecting a significant portion of the elderly female population, and yet, effective medical solutions for this condition remain elusive. This can be attributed to the complex nature of POP, where multiple factors, including tissue weakening and structural changes, contribute to its development. Despite the significant impact on women's quality of life, the absence of comprehensive treatment options underscores the urgency for innovative approaches to address this pressing health concern. In this context, 3D printing emerges as a valuable rapid prototyping tool, offering unique capabilities for designing and fabricating smart sensors and actuators. Its precision and versatility enable the creation of intricate devices that can be customized to specific medical applications. Moreover, 3D printing allows for the integration of sensors directly into biomedical devices, facilitating seamless monitoring and feedback mechanisms. Leveraging this technology, the research endeavors to harness the potential of 3D printing to develop advanced thermoelectric devices that can be seamlessly embedded within POP tissue scaffolds. These innovative devices will serve a dual purpose—detecting the health status of the tissue scaffolds and assessing their mechanical durability. In the realm of embedded medical devices, self-powered sensors hold particular significance due to their wireless powering capabilities and in-situ monitoring capabilities of human health. These sensors can operate without the need for external power sources or frequent battery replacements, making them ideal for long-term implantation within the human body. By tapping into the body's own energy sources or ambient environmental factors, self-powered sensors ensure continuous data collection and transmission, enhancing the efficiency and reliability of healthcare monitoring systems. Consequently, this talk aims to demonstrate the feasibility of 3D-printed thermoelectric devices as self-powered sensors, integrated into POP tissue scaffolds. These innovative devices will play a pivotal role in monitoring the tissue scaffold's condition, ensuring its mechanical integrity, and ultimately contributing to improved healthcare outcomes for women affected by POP.
(Invited) Catalyst and Anode Design for Durable Alkaline-Membrane Electrolysis
Authors: Boettcher Shannon W.
Published: August 2024

Commercialized membrane electrolyzers use acidic proton exchange membranes (PEMs). These systems offer high performance but require the use of expensive precious-metal catalysts such as IrO2 and Pt that are nominally stable under locally acidic conditions. Alkaline-exchange-membrane (AEM) electrolyzers in principle offer the performance of PEM electrolyzers with the ability to use earth-abundant catalysts and inexpensive bipolar plate materials. I will highlight our fundamental work in understanding the chemical and electrochemical processes in earth-abundant water-oxidation catalysts over the past decade and we are using that understanding to drive progress in high-performance AEM electrolyzers.

Baseline systems operate at 1 A·cm-2 in pure water feed at < 1.9 V at a moderate temperature of ~70 °C using either IrO2 or Co3O4 anode catalyst layers, PiperION alkaline ionomers, and stainless-steel porous transport layers. These devices, however, degrade rapidly compared to PEM electrolyzers which we link to chemical and structural changes in the ionomer-catalyst reactive zone using a combination of integrated reference-electrode device architectures, impedance, and cross-sectional and post-mortem materials analysis. We further discover that dynamic Fe-based OER catalysts – that have world-record performance in traditional liquid alkaline electrolyzer systems – perform poorly with enhanced degradation rates in alkaline membrane electrolysis, illustrating fundamentally different chemical design principles for OER catalysts.

Given this baseline understanding, I will end with new chemical strategies we have developed to mitigate degradation and enhance performance using novel ionomers, passivated electrolyte-catalyst interfacial architectures, and specifically designed multicomponent anode oxygen catalysts to target stable performance without supporting soluble electrolyte: <10 μV/h degradation at currents > 2 A cm-2 and cell voltages < 2V.
Enhanced Dynamic Operational Stability of Ni-Based Electrodes for Alkaline Water Electrolysis
Authors: Kim MinJoong , Cho Hyunseok , Lee CHangsoo , Lee Sechan , Doo Gisu , Seo Jongsu , Park Hyeonjung
Published: August 2024

Due to the accelerating paradigm shift toward renewable energy, water electrolysis systems have been evaluated for their ability to act as long-term renewable energy stores, wherein the energy is stored in the form of hydrogen gas. However, when renewable energy sources are employed, the power provided is intermittent, so developing highly active and durable electrode materials that function under these conditions is necessary. In particular, the irregular power supply accelerates severe degradation of the Ni-based electrodes due to irreversible surface oxidation, structural defects or collapse of the layered structure. Herein, we designed and fabricated Ni-based binary electrodes for alkaline water electrolyzers (Ni-Al & Ni-P electrodes for HER, Ni-Fe LDH electrodes for OER), and evaluated their electrochemical performance under dynamic operating conditions. Importantly, no significant OER & HER performance degradation was observed after the lab-scale dynamic operation tests, and no structural deformation or metal ion dissolution was found to occur. We further demonstrated the stability under the dynamic using advanced analysis and simulation techniques (XAS, in-situ ICP-MS, DFT calculations)
(Invited) U.S. Department of Energy’s Hydrogen and Fuel Cell Perspectives
Authors: Esposito Anne Marie , Miller Eric , Peterson David , Hubert McKenzie
Published: August 2024

The U.S. Department of Energy (DOE) is supporting a comprehensive research, development, demonstration, and deployment (RDD&D) effort to address the challenges to achieving large-scale commercial viability of hydrogen and related technologies across sectors and applications. An overview will be provided on DOE’s Hydrogen Program, including the National Clean Hydrogen Strategy and Roadmap, and key priorities within the Bipartisan Infrastructure Law, which includes $8 billion for the Regional Clean Hydrogen Hubs and $1.5 billion for the Clean Hydrogen Electrolysis, Manufacturing and Recycling Programs. The presentation will discuss how hydrogen RDD&D activities are advancing the U.S. commitment to tackle the climate crisis through the DOE Hydrogen Program’s H2@Scale vision for clean hydrogen across the economy, and the Hydrogen Energy Earthshot; seeking to cut the cost of clean hydrogen to $1 per 1 kilogram in one decade. A focus of this presentation will be on low temperature electrolysis activities led by DOE’s Hydrogen and Fuel Cell Technologies Office and will include a discussion on current status, key targets, and remaining challenges that need to be addressed to meet Clean Hydrogen Electrolysis Program and Hydrogen Shot goals.
(Invited) Electrode Transport Resistance Analysis in Proton Exchange Membrane Water Electrolyzers
Authors: Litster Shawn , Ferner Kara J , Ebbert Mary , Pasmay Fausto N
Published: August 2024

Decarbonizing sectors that are challenging and economically demanding to electrify, such as heavy-duty ground transportation, aviation, and industries like ammonia, steel, petroleum refining, synthetic fuels, and cement production, is crucial in addressing climate change and environmental pollution. The key strategy for reducing the reliance of these sectors on fossil fuels and cutting emissions involves utilizing hydrogen with low carbon intensity. Proton exchange membrane water electrolyzers (PEMWEs) play a vital role in this transition due to their high efficiency, rapid response time, and capability to electrochemically compress hydrogen. However, despite making encouraging progress, significant improvements in catalyst activity and utilization are necessary to lower loadings to levels that meet ambitious cost targets.

One critical aspect of enhancing catalyst performance for achieving high currents at efficient low voltages is minimizing overpotential losses. These losses result from electron, proton, and water transport to the oxygen evolution catalysts. Additionally, there are secondary current-induced loss mechanisms, including membrane and electrode dry-out and ionic contaminant polarization.

In this presentation, we will delve into the relevant transport mechanisms and the fundamental limits of reducing these overpotentials through modeling. We have evaluated the transport properties of electrodes that are challenging to directly probe due to their micrometer and sub-micrometer length scales using ultra-high-resolution three-dimensional imaging with X-ray computed tomography (nano-CT) and plasma-focused ion beam cross-sectioning with scanning electron microscopy (pFIB-SEM) for image-based simulations. Subsequently, we will briefly review existing methods for experimentally diagnosing transport limitations, as well as highlight new methods currently under development in our laboratory. These new diagnostics include a galvanostatic intermittent titration technique (GITT) for electrolyzers and a limiting-current diagnostic for PEMWEs. The presentation will conclude by highlighting fresh insights into the significance of two-phase transport, electrode and membrane dry-out, all enabled by these diagnostics and modeling.
Novel Ru-Based PEM Electrolysis Catalyst – Development from the Nano- to the Industrial-Scale
Authors: Gebauer Christian , Marić Robert , Bulic Matej , Ashley Mike , Swisher Jordan
Published: August 2024

For the de-fossilization of sectors like chemicals, steel, and transportation, green H2 generated via water electrolysis provides a path towards net-zero. The broad use of H2 across hard-to-abate sectors confirms the urgent need for green hydrogen at scale.

Within water electrolysis, there are several competing technologies: the so-called solid oxide electrolysis cell (SOEC), alkaline water electrolysis (AEL) and polymer electrolyte membrane electrolysis (PEM EL). Here, the latter shows significant benefits, such as high current density operation (> 2 A/cm2) and thus a smaller footprint, highly dynamic operation mode, high gas purity, and generation of pressurized hydrogen. However, at present, PEM EL requires precious metal catalysts; in particular, the O2 evolution on the anode currently relies on iridium, a metal which is rather scarce and expensive [1].

To meet the demand of iridium with respect to the announced increase in electrolyzer capacities in the multi-GW range, material innovation to reduce the use of this precious metal must be implemented. Successful catalyst and electrode developments have already been demonstrated in the BMBF funded project Kopernikus P2X, whereby loadings of approx. 0.3 mg/cm2 (< 0.1 g/kW1) have been achieved without any significant losses in activity over time [2, 3].

Here, we present a material innovation in the form of Ru-based electrocatalysts with a significantly reduced Ir content. This ruthenium-iridium oxide can be adjusted in a wide range of Ir content down to less than 15 wt.% (Ir). Consequently, iridium-based electrode loadings of less than 0.1 mg/cm2 and mass activities of about 3,500 A/g are feasible. Moreover, in accelerated degradation tests those mixed-oxides have demonstrated the often-missing stability by showing low degradation rates, similar to that of pure IrO2, in up to 30,000 potential-induced stress cycles.

This achievement stems from a remarkable screening approach that combines synthesis, characterization and testing at the nanoscale at Mattiq, and on industrial scale in the multi-gram range at Heraeus Precious Metals GmbH & Co. KG. Remarkably the alignment of degradation testing on both scales showcases the power of the applied method, providing a blueprint for high throughput screening for future material developments, both within water electrolysis and beyond.

References

[1] “Iridium Quaterly Market Report“, SFA Oxford (2021) 31

[2] M. Bernt, A. Hartig-Weiß, M.F. Tovini, H.A. El-Sayed, C. Schramm, J. Schröter, C. Gebauer, H.A. Gasteiger, Chem. Ing. Tech. 92, 31 (2020)

[3] M. Möckl, M.F. Ernst, M. Kornherr, F. Allebrod, M. Bernt, J. Byrknes, C. Eickes, C. Gebauer, A. Moskovtseva, H.A. Gasteiger, J. Electrochem. Soc. 169, 064505 (2022)
(Invited) Development of Ir-Based Electrocatalyst for Proton Exchange Membrane Water Electrolysis
Authors: Ito Mizuki
Published: August 2024

PEMWE (proton exchange membrane water electrolysis) is one of the most prospective way to produce hydrogen without environmental damage. So far, various materials have been studied for more efficient water electrolysis. These studies have mainly focused on anode-side material since the over potential for the anode side reaction (H2O → 1/2O2 + 2H+ + 2e-) is much higher than that of the cathode side reaction (2H++2e- → H2).

Among various materials, iridium oxide (IrOx, IrO2) is one of the most superior anode side material. As a company, which address PGM (platinum group metal) and their technologies, we have been developing the iridium-based catalyst for PEMWE.

We have TEC77100, TEC77110 etc. as catalyst line-up for water electrolysis. TEC77100 is an amorphous-type iridium oxide catalyst with large surface area which reaches about 100 m2 g-1, whereas, TEC77110 is a crystalline (rutile) -type catalyst with high durability. The amorphous-type TEC77100 shows higher activity (–1.86 V@2A cm-2, 50°C, measured in MEA with NafionTM 115 membrane) than the rutile-type TEC77110 (–1.92 V@2A cm-2, 50°C). In terms of durability, however, TEC77110 is superior to TEC77100. The degradation was suggested to be due to the crystallization of TEC77100 under water electrolysis condition. Except for these two types of catalyst, I’ll also introduce a catalyst to countermeasure cross leaking hydrogen in the anode side from the cathode side briefly.

Figure 1
(Invited) Hierarchically Structured Electrocatalysts Using Scalable Synthesis Techniques for Membrane Water Electrolyzers
Authors: Peron Jennifer
Published: August 2024

Beyond composition, the morphology of catalyst particles is a key-parameter to allow for a high accessibility to catalytic sites but it is also of paramount importance to manage gases and water transport within catalyst layers in membrane-electrode assembly based devices. Besides their electrochemical activity, fabricating high performance catalysts and catalyst layers that are compatible with industry fabrication processes is critical for their implementation in commercial electrochemical devices. Considering these requirements, we are developing green, cheap and scalable solution synthesis techniques to prepare hierarchically structured catalysts that can be readily incorporated into catalyst layers.

Two strategies will be discussed. We have recently introduced an aerosol synthesis technique for the preparation of highly porous iridium pure and mixed oxides that are highly active and stable towards the Oxygen Evolution Reaction in acidic media. Beside beeing ideally suited for the preparation of highly porous catalyst layers, the hierarchical morphology can also be used for fundamental studies [1] or used as a probe to follow the catalyst degradation in PEM water electrolysis devices.[2]We also implemented the well-known polyol process [3] to prepare heterofunctional catalysts with ultra-low PGM content that are active towards another challenging reaction in anion exchange membrane water electrolyzer: the Hydrogen Evolution Reaction in alkaline media. The structure-properties relationship in these materials is assessed by a large set of techniques including SEM, XRD, XRF and STEM-EDX as well as surface (XPS) and bulk (XAS) characterizations, including operando XAS.

Nature Communications,
2021, 12, 3935, 1038/s41467-021-24181-x

Chemistry of Materials,
2023, 35, 20, 8590–8598,
1021/acs.chemmater.3c0152.

Chem. Soc. Rev.
, 2018, 47, 5187-5233,
10.1039/C7CS00777A
Exploring the Role of Coordinating Environments on Durability of Nickel-Based Catalysts for Hydrogen Evolution Reactions
Authors: Yang Kevin , Friedman Ariel , Mukerjee Sanjeev
Published: August 2024

Ni-based platinum-group-metal (PGM)-free catalysts for hydrogen evolution reaction have been considered viable for the commercialization of alkaline exchange membrane water electrolysis (AEMWE) due to their high activity and low cost. Even though several highly active Ni-based catalysts have been developed in recent years, their long-term stability under commercially relevant conditions was not systematically assessed, preventing a direct comparison with the currently used catalysts. While not as active, the current commercial PGM-free catalysts are highly stable, with an operational life measured in decades. However, conducting durability assessments through long-term durability studies can take over 10,000 hours which is impractical. Consequently, accelerated stress tests (ASTs) specifically targeting the catalyst and simulating uncontrolled shutdown and high overpotential scenarios are needed to further improve AEMWE technology.

In this presentation, the ASTs of several Ni-based catalysts with different coordination environments (nickel molybdenum, nickel cupferron1, Ni-NiO, and a novel high surface area de-alloyed Ni catalyst) will be explored. The catalysts were subjected to high overpotentials and uncontrolled shutdown cycles in both liquid electrolyte and AEMWE cells. The structure of these catalysts was observed using in situ Raman spectroscopy, XRD, TEM, and BET gas adsorption analysis and correlated to changes in electrochemical performance. The determination of the catalyst structure during these ASTs is paramount in designing durable PGM-free catalysts for improved AEMWE performance.

1) Doan, H.; Kendrick, I.; Blanchard, R.; Jia, Q.; Knecht, E.; Freeman, A.; Jankins, T.; Bates, M. K.; Mukerjee, S. Functionalized Embedded Monometallic Nickel Catalysts for Enhanced Hydrogen Evolution: Performance and Stability. J. Electrochem. Soc.
2021, 168 (8), 084501. https://doi.org/10.1149/1945-7111/ac11a1.
Understanding the Reaction Activity of Ni(1-x)FexOH Towards Oxygen Evolution Reaction
Authors: Costa Figueiredo Marta
Published: August 2024

The development of electrocatalysts towards the oxygen evolution reaction based on earth-abundant and cheap materials, such as transition metal oxide and hydroxide, is crucial to reduce the emission of CO2 and slowdown the global warming [1]. Among these transition metal compounds, ferromagnetic electrocatalysts usually exhibit promising activities towards OER due to their unique electron spin properties [2]. Applying an external magnetic field can further tune the electron spin polarization of ferromagnetic materials and, therefore, improve the OER activity. However, evaluating the activity of these electrocatalysts towards OER remains challenging. For example, the electrocatalysts will undergo activation under reaction conditions (frequently due to Fe insertion), which brings difficulties in determining the real reaction sites as well as establishing the “structure-activity” relationship [3]. In addition, the overall measure activity (current density) is contributed by multiple factors such as intrinsic kinetics, mass transfer, conductivity, etc., which strongly depend on operation conditions. In this talk, I will present our recent study of OER on Ni(1-x)FexOH [4]. Electrochemical impedance spectroscopy (EIS) and quasi-in situ XPS will be applied to obtain the contribution from different reaction parameters and understand the intrinsic activity.

[1] McCrory, C. C. L. et al. Benchmarking Hydrogen Evolving Reaction and Oxygen Evolving Reaction Electrocatalysts for Solar Water Splitting Devices. Am. Chem. Soc.
137, 4347–4357 (2015).

[2] Ren, X. et al. Spin-polarized oxygen evolution reaction under magnetic field. Commun.
12, 1–12 (2021).

[3] Jung, S., McCrory, C. C. L., Ferrer, I. M., Peters, J. C. & Jaramillo, T. F. Benchmarking nanoparticulate metal oxide electrocatalysts for the alkaline water oxidation reaction. Mater. Chem. A
4, 3068–3076 (2016)

[4] Wei Chen, Laura Donk, Tiago Fernandes, Anna Kitayev, ErvinTal Gutelmacher, Yury V. Kolen’ko, Marta C. Figueiredo*, in preparation.