bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) novel Charged Interfaces for Catalysis and Energy Conversion
Authors: Fan Feng Ru
Published: September 2023

Charged interfaces are ubiquitous in many research fields such as electrochemistry, catalysis, and energy chemistry, and are key places where physical and chemical processes occur. The charged interface structure can also be affected by external fields such as light, electricity, and force, and becomes the key to regulating chemical reactions. It is of great significance for the development of surface and interface science, electrochemistry, catalysis and energy science to deeply understand the physical and chemical reaction process and mechanism of various charged interface systems, and to clarify the interaction between interface structure and reacting species. It is extremely challenging to rationally design, construct, and characterize various novel charged interfaces, and then comprehensively and deeply study their physical and chemical processes and mechanisms. By constructing new charged interface structures such as solid/solid triboelectric interface, micro-droplet charged liquid/gas interface, and metal/two-dimensional material charged interface, we study the reaction process and mechanism of the charged interface and develop new energy conversion pathways. A series of innovative research results: Discovered a new mechanism of triboelectric power generation, expanding the new direction of charged interface structure in energy conversion; established and developed epitaxial growth modes of various interface structures; accurately characterized the electron transport of charged interface structure and surface charge distribution and other physical and chemical properties.

We have developed new systems such as solid/dielectric/liquid charged interfaces based on electrodes/dielectric layers/electrolytes and liquid/gas charged interfaces based on microdroplets, and explored new applications in energy conversion and electrocatalysis. Applying a voltage to the electrode/dielectric layer/electrolyte interface can polarize the dielectric layer and adsorb ions in the electrolyte, forming a special "sandwich" electric double layer. Different from the solid/solid charged interface formed by triboelectrification or light excitation, this is a new solid/dielectric/liquid charged interface system based on electrostatic adsorption. Based on this interface system, a new nanoscale power generation device is designed, which can effectively convert mechanical energy into electrical energy, and has high output performance. A new liquid/gas charged interface based on micro-droplets was constructed by means of electrospray, a new strategy for confining the liquid/gas charged interface was proposed, and a high-performance electrolytic water catalyst was prepared. The physical and chemical mechanism of accelerated chemical reactions at the liquid/gas charged interface is revealed, and the desolvation effect and interface confinement effect are proved to be effective ways to construct defect-rich electrocatalysts.
(Invited) accelerating Polymer Discovery for Multifunctional Polymer Thin Films: High-Throughput Characterization
Authors: Quinn Harley J , Wang Wenlu , Werner Joerg G , Brown Keith A
Published: September 2023

Identifying new formulations of polymers that have multiple highly tuned properties is a grand challenge of materials development. This is especially important in polymer thin film devices where several distinct transport properties must be controlled. For instance, solid-state battery electrolyte materials must be conductive to ions, but remain electronically insulating. In order to achieve the materials advances needed to transform the use of such polymer thin films, new paradigms of accelerated materials development are needed.

In this talk, we discuss our recent efforts to accelerate the development of advanced polymer thin film materials for energy applications. A crucial feature of accelerating the discovery of high performing formulations and processing conditions is a rapid means to assess the properties of polymer films with spatial resolution commensurate with nanoscopic defects and throughput that can accommodate macroscopic devices. We initially focus on the challenge of verifying that films are electrically insulating. Maintaining electrical insulation across large films is a particularly insidious challenge as small “pin-hole” defects can result in an entire device failing. We explore an optical method to detect and characterize conductive defects based upon the electrochemiluminescence of luminol. In particular, when a voltage is applied to a conductive surface that is protected by a nominally insulating film, regions where the film is not present or is electrically conductive will result in the local generation of light. A major virtue of this approach is that the minimum detectable feature is not directly determined by the wavelength of light or the optical magnification in use, but rather the intensity of light generated per unit area on the surface. To explore this approach, we conduct an extensive series of optimization experiments to maximize the intensity of light generated by electrochemiluminescence by adjusting the timing, voltage, and solution properties. The result of this optimization is that lines narrower than 100 nm are readily detectable using this method. Finally, we present efforts to use this approach to screen centimeter-square areas to find and characterize nanoscale defects.

Looking beyond the important task of characterizing films at high throughput, we conclude the talk with a discussion of how this approach fits in a broader materials discovery pipeline. In particular, recent years have seen a number of examples of autonomous experimentation systems that combine automation to perform experiments and machine learning to select experiments to vastly increased the speed at which knowledge is gained. The reported high-throughput analytical process is anticipated to form an important link in this process by providing a path to rapidly and effectively screening films for electrical properties.
(Invited) empowering Triboelectric Nanogenerator with Functional Polymers for Environment Monitoring
Authors: Chang Chia-Chih
Published: September 2023

Triboelectric nanogenerator (TENG) proves useful as self-powered sensor. Integration of TENG with functional polymers empowers TENG to exhibit new functionalities and stimuli responsiveness. This study describes the evaluation of spiropyran-functionalized polymer (P1) and guanidinium-functionalized polymers (2 Gdm.) as new materials for TENG, which both show tunable triboelectric output voltage in response to various environmental cues including UV irradiation, humidity change, metal ions and the presence of bacteria. Spiropyran isomerizes to merocyanine upon UV irradiation for 100s (6-8W), resulting in a decrease in output voltage from 100 V to 65 V. In addition, the output voltage is inversely proportional to the irradiation time. Noting high humidity (RH) generally limits the performance of conventional TENGs, such that the output voltage decreases as RH increases. The output voltage of P1 decreases by 48% (from 100V to 52V) and the output voltage of 2 Gdm. decreases by 85% (from 100V to 15V) as the RH changes from 25% to 88%, which is a common behavior of TENG under high humidity. In contrast, the output voltage of the UV irradiated P1 TENG increases by 30% (from 65V to 80V). Because merocyanine is capable of chelating with metal ions to form metal complexes, we also evaluate the effect of metal chelation on triboelectric voltage output. Chelation with copper(II) ions result in restoration of output voltage to ~100V, suggesting the relative position in triboelectric series can be modulated by metal complexation. For guanidinium-functionalized polymers, 2Gdm., the inherent antimicrobial properties of guanidinium side groups enables TENG to be sensitive to both gram-positive and gram-negative bacteria at a concentration of 105 CFU/mL, resulting in decreasing output voltage as bacteria concentration increases. These results demonstrate that the functionalized polymers can be used as a responsive motif to realize smart TENG systems, which exhibits sensitivity to UV irradiation, changes in humidity, and the presence of metal ions or bacteria.
(Invited) nanoengineered Surfaces for Modulating Cell-Surface Interaction and Sensing Applications
Authors: Bachhuka Akash
Published: September 2023

The greatest challenge in the field of biomaterials is the understanding and prediction of long-term biological responses in patients receiving implantable materials. Reconstructing and detailing these mechanisms may allow for more targeted approaches and highlights how immune processes are amenable to manipulation by synthetic biomaterials. Surface nanotopography and chemistry are critical factors in integrating implanted devices into tissues and in the satisfactory resolution of the wound healing process. However, how the interplay between surface chemistry and nanotopography may influence inflammatory and wound-healing pathways remains unanswered. To address this gap, 2D and 3D surfaces with nanotopography of controlled height (16, 38, and 68 nm) and lateral spacing with uniform outermost surface chemistry tailored with plasma polymerized amines (NH2), carboxyl (COOH-) and hydrocarbon (CH3-) functionalities were fabricated. These surfaces were employed to study cellular responses responsible for implant encapsulation, wound healing, and tissue regeneration. The data shows that the right combination of chemistry and nanotopography can modulate cellular adhesion, proliferation, self-differentiation, collagen deposition, and the expression of anti and pro-inflammatory signals.

Furthermore, our surface engineering expertise was utilized to fabricate metal ion sensors and biosensors based on nanoporous anodic alumina (NAA) and gold nanoclusters (AuNCs). We anticipate that future explorations in this field of research will facilitate the rational design of biomedical implants and devices with physicochemical surface characteristics tailored at the nanoscale that will enhance utility and function and improve clinical outcomes.
(Invited) soft, Wireless Pressure-Sensor-Integrated Smart Bandage for the Management of Wound Healing
Authors: Wang Xueju
Published: September 2023

Soft, flexible electronics are promising for many applications including health monitoring, soft robotics, and other intelligent systems. In this talk, I will discuss our recent efforts in developing flexible electronic devices with previously inaccessible capabilities. I will start with our work on soft, wireless pressure-sensor-integrated smart bandage for the management of diabetic foot ulcers. Diabetic foot ulcers (DFUs) have affected millions of people in the U.S. and posed heavy burdens to patients and the healthcare system due to their being slow to heal, high recurrence rate, and potential risk of amputation and even premature death. A mainstay of DFU therapy is mechanical offloading to mitigate pressure at the ulcer, which, however, is usually not effective due to patients’ diminished sensation capabilities on the foot and low adherence to offloading recommendations. I will present our recent effort in developing a soft, flexible, wireless pressure-sensor-integrated smart bandage system for continuously monitoring the pressure on the foot and alerting the users to offload under exceeded pressure. The pressure sensor exhibits high linearity, negligible hysteresis, fast response time, and excellent water-proof properties relevant for this application. Wireless data transmission onto a smartphone via Bluetooth enables the display and interpretation of the measured pressure with the option of a preset pressure threshold, when exceeded, an alert will be generated for immediate notifications. Trials on healthy subjects demonstrate reliable monitoring performance and effectiveness in aiding offloading. The developed smart bandage system represents a significant advance in the prevention and management of DFUs and other pressure injuries as well as compression therapy corrections.
(Invited) seamless Integration of Electronics, Electrochemistry, Microfluidics, and Materials for Next Generation Tissue-Integrated Sensors and Energy Devices
Authors: Bandodkar Amay J
Published: September 2023

Recent advances in materials, mechanics, and device architectures form the foundations for rapidly emerging classes of sensors and energy devices with mechanical characteristics that allow for conformal interfaces with the soft, curvilinear surfaces of the human body. While the field of tissue-integrated biophysical sensors exhibits commendable progress in capturing clinical quality thermal, kinematic, and electrophysiological information, the advancement of complementary biochemical sensors severely lags due to unique challenges associated with seamless integration of delicate biochemical receptors, transducing components, and suitable packaging materials. Similarly, the vast majority of demonstrated tissue-mounted energy storage and energy harvesting systems unfortunately rely on toxic components that substantially diminish their attractiveness in bio-related applications. In this talk, I will discuss non-traditional approaches to address some of these grand challenges. Specifically, I will discuss three technologies that my lab is developing -1) wearable, self-powered sweat sensors for non-invasive health monitoring 2) wireless, implantable, battery-free sensors and optoelectronics for neuroscience research, and 3) fully resorbable batteries for broad applications in medicine and consumer electronics.
(Invited) 3D Morphable Electronic Systems Via Deterministic Microfolding
Authors: Bai Wubin
Published: September 2023

DNA and proteins fold in three dimensions (3D) to enable functions that sustain life. Emulation of such reversible folding schemes for functional materials can create promising opportunities for advancing a wide range of technologies. In particular, morphing 3D mesostructures via multiple dimensions for high-performance materials including monocrystalline silicon can enable unconventional designs in sensory robotics, biomedical devices, microelectronics, and microelectromechanical systems. Existing approaches to morphing functional materials mostly rely on planar processes, which often complicates needed mechanisms for structural reconfiguration and limits the choice of materials composition and dimension. This presentation will introduce a bioinspired microfolding strategy to realize 3D reconfigurable microelectronic systems in freestanding forms with various advanced materials and complex architectures. The microfolding mechanism allows access to any transitional states of the folded 3D structures in a reversible fashion, to modulate functionalities on demand. Demonstrations on microantennas for telecommunication, wearable accelerometers for tremor monitoring, and epicardial bioelectronic probes for cardiac mapping, all of which are achieved via the microfolding strategy, further highlight the high potential for a broad range of applications in healthcare and communications industry.
(Invited) inkjet-Printed Soft Electronic Devices and Sensors for Wearable Health Monitoring Applications
Authors: Wang Chuan
Published: September 2023

Stretchable electronic devices and sensors built on thin elastomer substrates may find a wide range of applications in wearable health monitoring devices owing to their ability to conformably adapt to human skin for long-term and comfortable wearing. In this talk, I will present our work on developing intrinsically-stretchable electronic materials that are formulated as electronic inks and patterend using a highly scalable and low-cost inkjet printing process. A variety of soft sensors including silver nanoparticle based ultrasensitive resistive strain sensor and pressure sensor, porous elastomer dielectric based capacitive pressure sensor, and multimodal sensor that can differentiate pressure, strain, and temperature stimuli have all been demonstrated on ultrathin polydimethylsiloxane (PDMS) substrate by printing. These devices have been used in applications including motion and gesture tracking, voice recognition, arterial pulse waveform and photoplethysmogram monitoring. In addition, I will also report our work on the development of a unique porous PDMS sponge electrode as a gel-free dry interface for motion-artifact tolerant recording of electrophysiological signals. The porous structure of the soft electrode significantly increases the effective contact area and lowers the electrode-skin impedance, which result in improved signal-to-noise ratio. Compared to commercial rigid electrodes, the soft and thin form factor also makes the spongy electrode well-suited for long-term recording of high quality biopotential signals including electrocardiogram (ECG) and electromyography (EMG) on ambulatory patients. As a demonstration of its clinical usage with a focus on maternal and fetal health monitoring, I will show an array of such soft electrodes integrated on a printed patch of textile-based interconnections, and used for recording and spatiotemporal mapping of the uterine contraction patterns from patients in active labor.
The Study of the Influence of a Natural Electrostatic Field on Cells in Culture
Authors: Lee Donghan , Kang Dayoon , Cho Sumin , La Moonwoo , Jang Jinah , CHOI Dongwhi
Published: September 2023

We live in a sea of natural electrostatic fields today. All materials with different electron affinity obtain electrostatic charges based on triboelectrification due to their numerous accidental frictions. Therefore, they are forming their own electrostatic fields. Cells in culture are also in multiple electrostatic environments. Nevertheless, in most cases, cells have still been cultured without considering the influences of natural electrostatic fields. However, given that many studies about the influences of man-made electrical stimulation on cells have been reported, it is necessary to discern the distribution of the electrostatic fields around culture dishes and analyze their effects on the cells for a more controlled culturing environment and a consistent result. Herein, we investigate the factors that contain electrostatic charges as abundant as exert an influence on cells by measuring the electrostatic field around culture dishes. In addition, we analyze the influence by comparing the results of culture between an ordinary laboratory condition and a controlled condition of a neutral electrostatic environment where the electrostatic field is blocked.
(Invited) Decoupling Strategies in Electrochemical Water Splitting
Authors: Symes Mark
Published: September 2023

The storage of renewably-generated energy as hydrogen via the electrolysis of water is a fundamental cornerstone of a sustainable hydrogen economy. Conventional electrolysers usually require stable power inputs in order to operate effectively and safely and so may be unsuited to harnessing renewable power, which is often intermittent and diffuse. Decoupled Electrolysis (see, for example: Nature Chem.
2013, 5, 403-409; Science,
2014, 345, 1326-1330; J. Am. Chem. Soc.
2016, 138, 6707–6710; Joule, 2018, 2, 1390-1395; Adv. Energy Mater.
2020, 2002453; Electrochim. Acta,
2020, 331, 135255) has the potential to overcome some of the challenges surrounding electrolysis using low and/or sporadic power inputs (especially those related to gas crossover) as the decoupling of the two half reactions of water splitting allows the oxygen and hydrogen evolution reactions to be performed at different times, in different places and at rates that are not linked to each other. In this talk, we shall give an overview of decoupled electrolysis using liquid redox mediators and also explore the use of decoupling agents in other contexts such as redox flow batteries (Nature Chem.
2018, 10, 1042-1047) and electrosynthesis (Chem. Commun.
2018, 54, 1093-1096).

Figure 1
Optimization of Time-of-Flight Secondary Ion Mass Spectrometry for Analysis of Porous Transport Layers
Authors: Stelmacovich Genevieve , van Eijk Lonneke , Walker Michael , Cullen David A. , Ware Sam , Young James L. , Bender Guido , Pylypenko Svitlana
Published: September 2023

As we move towards commercialization of the proton exchange membrane water electrolyzers (PEMWEs), fundamental understandings of individual components and their integration with focus on material composition and its correlation to performance and lifetime of electrolysis cell operation is of significant importance. Porous Transport Layers (PTLs) increase overpotential of the cell when the titanium passivates, i.e. develops a titanium oxide surface layer of a certain thickness. To prevent this passivation, platinum group metal coatings are typically applied to the PTL, but this adds significant costs.

This presentation will cover recent developments in characterization of PTL coatings and PTL-coating interfaces using Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) in correlation with Scanning Transmission Electron Microscopy and Energy Dispersive X-ray Spectroscopy (STEM-EDS) analysis. Although this technique is extremely beneficial, ToF-SIMS is typically applied to flat substrates and therefore has been mainly utilized in other scientific fields such as the thin film industry. This talk will discuss method validation and optimization that has been conducted for PTL analysis to allow its characterization by ToF-SIMS. Topics include understanding parameters and limitation of using SIMS on these morphologically challenging samples, as well as looking at elemental and species identification, and applying depth profiling to gauge information on coating and oxide thickness and their consistency. Correlations between real and flat substrates prepared under similar conditions are made, allowing standardization of depth profiling for future analysis of a wider variety of samples.
Gas Crossover and Supersaturation in Advanced Alkaline Water Electrolysis
Authors: Lira Garcia Barros Rodrigo , Kraakman Joost , de Groot Thijs Theodorus , van der Schaaf John
Published: September 2023

Conventional alkaline water electrolyzers operate with a finite-gap between the cathode and anode [1]. The ohmic resistance induced by this finite-gap results in energy losses. Therefore, the zero-gap assembly is considered an attractive configuration to perform advanced alkaline water electrolysis. However, gas crossover is enhanced in the zero-gap configuration by supersaturated hydrogen concentrations in the vicinity of the electrode. To avoid excessive gas crossover there is a limiting minimal operational current density.

Different transport mechanisms can contribute to gas crossover through the porous separator, namely diffusion, convection, and electrolyte mixing. For well-balanced pressures and industrial flow rates, diffusion is the main contributor to gas crossover [2].

Local supersaturation at the diaphragm interface significantly contributes to gas crossover [2]. To confirm this hypothesis, in-situ gas analysis experiments were conducted in an electrolysis setup equipped with in-line gas chromatography that could be operated with negligible influence of convective transport mechanisms to evaluate the diffusive transport in both zero- and finite-gap configurations.

There is a clear distinction in gas crossover between zero- and finite-gap designs. In Figure 1 is shown that for the zero-gap assembly, hydrogen crossover rates were found to increase with current density, evidencing that supersaturation at the diaphragm interface plays an important role on gas crossover. In contrast, using a finite-gap configuration, gas crossover was significantly reduced and approached equilibrium diffusion rates, proving that gas crossover is mainly driven by diffusive hydrogen transport. Therefore, advanced alkaline electrolysis could be operated at higher current densities by applying a zero-gap configuration and reducing diaphragm thickness, but gas crossover leads to higher hydrogen in oxygen levels at low power load.

[1] J. Brauns, T. Turek. “Alkaline water electrolysis powered by renewable energy: A review”. Processes, vol. 8, no. 2 (2020).

[2] M. T. de Groot, J. Kraakman, R. Lira Garcia Barros. “Optimal operating parameters for advanced alkaline water electrolysis”. International Journal of Hydrogen Energy, vol. 47, no. 82 (2022) 34773-34783.

Figure 1
Electrochemical Analysis of Anion Exchange Membrane Water Electrolyzers (AEMWE)
Authors: Nuggehalli Sampathkumar Suhas , Ferriday Thomas B. , Middleton Peter Hugh , Van herle Jan
Published: September 2023

The increase in deployment of renewable electricity has made green hydrogen production an attractive solution for decarbonizing energy systems. The prominent technologies currently deployed are the proton exchange membrane water electrolyzers (PEMWE) and alkaline water electrolyzers (AWE). The PEMWE technology uses platinum group material (PGM) catalysts, coated onto fluorinated Nafion® polymer membranes and needs specially treated titanium bipolar plates, reaching current densities of greater than 2 A cm-2. The AWE technology, in contrast, uses cheaper materials with a porous diaphragm separator, but the operating current density reaches only <0.5 Acm-2. The anion exchange membrane water electrolyzers (AEMWE) combine the advantages of both the PEMWE and AWE by using hydroxide (OH-) conducting, functionalized styrene-based membranes with non-PGM electrocatalysts, reaching current densities of >1 Acm-2.

In this study, a membrane electrode assembly (MEA) consisting of Sustainion® X37-50 Grade RT membranes and non-PGM hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) electrocatalysts are fabricated and analyzed for performance. NiFe2O4 (Merk) was chosen as the OER electrocatalyst and spray-coated on the sintered 316L stainless steel fibre (dioxide materials). On the counter side, NiFeCo (USnano) as HER electrocatalyst was spray coated on the molded graphite layer 370 (MGL370- fuelcellstore) porous transport layer. A catalyst loading of 3 mg cm-2 is obtained for both HER and OER electrodes.

The fabricated MEA of 1x1cm2 is firstly tested for performance in a inhouse setup, using current density-voltage scans (j-V) using Zahner Zennium X electrochemical workstation. Consequently, electrochemical impedance spectroscopy (EIS) is performed in pseudo-galvanostatic mode. The perturbation amplitude is adjusted such that a linear region of the j-V curve is probed. The fuel electrode and air electrode contributions to the overall MEA performance are distinguishable due to the twin reference electrode configuration. The half cell-MEA contributions are further analyzed by performing parallel impedance measurements between the i) Reference electrode – cathode, ii) Reference electrode - Anode and iii) full-cell operation at predetermined current-density biases. These type of investigation gives deeper insight to the fuel electrode and the air electrode processes. The quality of the EIS spectra is analyzed using Kramers Krönig residual tests.

A sensitivity analysis on the MEA is performed by changing impedance-effecting parameters such as temperature, operating current density and potassium hydroxide (KOH) concentration. Further, post-test characterization of the electrode substrates is performed to identify affected parameters through XPS, Raman spectroscopy, SEM-EDX and XRD techniques. The parallel impedance measurements confirms the presence of anodic, cathodic and low-frequency diffusion processes in real time.
(Invited) Advancing Hydrogen Generation Technologies Assisted by a Solid International Benchmarking Effort
Authors: Carmo Marcelo , Ayers Katherine E. , Bender Guido , Bensmann Boris , Gago Aldo , Gottschalk Torben , Gross Karl , Hanke-Rauschenbach Richard , Jensen Jens Oluf , Kraglund Mikkel Rykær , Marina Olga A , Roberts George , Metz Sebastian , Smolinka Tom , Stechel Ellen B , Turek Thomas , Xiang Chengxiang("CX")
Published: September 2023

Water electrolyzers are today of worldwide strategic importance for the deployment of green hydrogen as an energy carrier, and the ultimate integration of stochastic renewable energies into the electrical grid at scale. Targets for the total cost of ownership of hydrogen have been constantly revised, but values around $1 to $2 per kilogram of H2 are generally accepted to reach parity with other energy conversion and storage strategies. However, further advancement of electrolyzers while maintaining durability and robustness of its cell/stack components is still needed. This can only be accomplished through focused research and development efforts that address efficiency, degradation, and cost aspects of the technology.

A growing number of research groups are starting to participate in this development with key contributions in the form of fundamental and material advances. However, the high deviation of reported results as well as the complex history the tests performed, and components used have shown that this growth creates challenges that hinder the development of trust in the test results generated. Moreover, such lack of trust ends up hampering the overall progress and leads to wasted allocated resources. Contributors to the HydroGEN Advanced water splitting Materials, Energy Materials Network; and H2-New programs funded by the Department of Energy in the USA; aligned with efforts by the International Energy Agency (IEA) within the Electrolysis Annex 30 are conducting a benchmarking effort: 1) to develop methods to identify reference hardware, cell components, and materials; and 2) to harmonize testing protocols and enable the meaningful comparison of performance across the community.

In this presentation, the latest results of this effort will be presented. The talk will also include updates on current strategies among the different teams, round robin testing results, protocol development and fine tuning of test parameters and material specifications. This effort should finally lead to the creation, validation, dissemination, and adoption of accelerated test protocols that can ultimately contribute to conducting collaborative studies on cell and stack degradation.
(Invited) Enabling Hydrogen at Scale Using Low-Temperature Electrolysis with Sustainable Materials
Authors: Mukerjee Sanjeev
Published: September 2023

This presentation will focus on durable, high-performance materials and interfaces for advanced water splitting, enabling a clear pathway for achieving <$2/KgH2 (on the scale) with an efficiency of 43 KWh/Kg using an anion exchange membrane interface. A fundamental understanding of hydrogen and oxygen evolution reactions (HER/OER) leading to novel materials will be presented in conjunction with critical improvements in membrane, ionomers, and gas evolution electrodes. Mechanistic details of the electrocatalysis, particularly the hydrogen evolution reaction, will be given with corresponding characterization and testing. This presentation will discuss fundamental aspects of HER in the context of a comprehensive series of models based on Pt and Pt alloys/ad-metals. A coherent picture of HOR/HER will pare with the general concepts of H-binding energy, shifts in the potential of zero charge, and the need for the presence of oxophiles on the surface. This presentation will show a comprehensive effort to enable such technology using Ni-based electrocatalysts using the concepts and models gleaned from fundamental studies on Pt based materials. Progress towards the end of the project goal of 1.76 Vcell(no-iR corrected) at 1A/cm2 will be highlighted wherein at the modeled scale of 50,000 kg/day and operating at 1 A/cm2 results in hydrogen cost at $2.15, $1.82, or $1.76/kg, respectively (2, 20, 200 plants). In addition, a road map for achieving $ 1/Kg in a decade will be delineated.
(Invited) Hydroxide Exchange Membrane Electrolyzers for Green Hydrogen: From Organic Chemistry to MW Stacks
Authors: Yan Yushan
Published: September 2023

With their increasing availability and rapid price decrease, clean electrons have been leading the way for our global decarbonization efforts. However clean electrons have limitations and cannot access certain sectors of our economy. Green hydrogen as a molecule has unique advantages over clean electrons in areas of chemical synthesis, heavy duty transportation, and long duration and cross sector energy storage. In this presentation I will share our past and latest work on hydroxide exchange membranes, electrocatalysis including electrochemical interface work, and the effort to develop a pure water-fed MW HEM electrolzyer stack.
(Invited) Catalysts and Interfaces for Low-Temperature Water Electrolysis
Authors: Jaramillo Thomas F.
Published: September 2023

Low-temperature water electrolysis is a promising means to employ renewable electricity and decarbonize H2 production, a molecule of great global importance with exciting prospects ahead. A number of R&D challenges remain in order to scale this technology for global impact. This paper will focus on several aspects design and development of low-temperature water electrolyzers: (1) low- or zero-precious metal catalysts for H2 and O2 evolution, and their integration into devices, (2) in-situ/operando synchrotron-based methods applied to catalysts, gas diffusion electrodes (GDEs) and membrane electrode assemblies (MEAs) to provide new insights into functioning systems, and (3) new device designs based on bipolar membranes (BPMs) and their resiliency with respect to impure water feedstocks. The overarching theme is the design of catalyst and interfaces informed by fundamental studies and their application toward functioning devices.
(Invited) Proton Exchange Membrane Electrolyzers Based on Sub-Micron Thick Membranes
Authors: Esposito Daniel V. , Yim Kyungmin , Fraga Alvarez Daniela V. , Cohen Lucas , Jin Jingjing , West Alan C. , Weimer Matthew S , Moulton Staci , Dameron Arrelaine A , Ayers Katherine E. , Capuano Christopher , Fortiner Serafina , Hawkes Justin , Glenn Jennifer
Published: September 2023

Significant decreases in the price of electricity from solar photovoltaics and wind are enabling concurrent decreases in the cost of clean hydrogen production by water electrolysis. However, to meet the US Department of Energy’s Hydrogen Shot Initiative target for levelized cost of hydrogen production of < $1 per kg of hydrogen by the year 2030,[1] it will also be necessary to drive down the capital costs of water electrolyzers. Reducing capital costs is especially important for scenarios where close to 100% of the electricity is provided by variable renewable energy generators, which greatly limits the capacity factor of the electrolyzer.[2] Towards this end, our team is exploring a proton exchange membrane (PEM) electrolyzer architecture based on ultrathin (< 1 micron) membranes. Modeling is used to show that defect-free membranes possessing appropriate proton and hydrogen transport properties present opportunities to decrease membrane resistances < 80% relative to conventional Nafion membranes, which can subsequently allow for operation at > 4 A cm-2 while maintaining the same efficiencies achieved by today’s commercialized PEM electrolyzers operated at < 2 A cm-2. Additionally, this talk will describe modeling and experimental efforts that address the viability of using sub-micron thick membranes that can operate with H2 crossover rates < 1%.

References

[1] US DOE Hydrogen Shot Initiative: https://www.energy.gov/eere/fuelcells/hydrogen-shot

[2] D.V. Esposito, Joule, 1, 1-8, 2017.
Poly(carbazole)-Based Anion Exchange Membranes Developed by Grafting Alkyl Ammonium Group
Authors: Adhikari Santosh , Klein Jeffrey Michael , Matanovic Ivana , Kim Yu Seung
Published: September 2023

AEM water electrolysis offers several advantages over proton exchange membrane water electrolysis such as the potential use of non-precious metal catalysts and less expensive bipolar plates. Therefore, there is a great demand for reliable, high-performing, durable, and low-cost AEMs for the technologies.1 In this presentation, we report polycarbazole-based AEMs by acid-catalyzed Friedel Craft’s polycondensation reaction followed by grafting with an alkyl ammonium group.2 Two AEMs, PDPC-3QA (IEC=1.25 meq./g) and PDPC-6QA (IEC=1.74 meq./g), were synthesized by grafting 3-bromo-N,N,N-trimethylpropan-1-aminium bromide (3-BrQA) and 6-bromo-N,N,N-trimethylhexan-1-aminium bromide (6-BrQA), respectively on the precursor polymer. While 100% grafting was achieved with 6-BrQA, only 60% of grafting was achieved with 3-BrQA due to the competition between the elimination and substitution reaction on 3-BrQA because of the higher acidity of β-hydrogen resulted from the proximity of the bromide and ammonium groups. With high OH- conductivity (103 mS/cm at 80 °C) and excellent alkaline stability (< 3% conductivity loss after 500 hours in 1 M NaOH at 80 °C), PDPC-6QA exhibits promising water electrolyzer performance.

References:

E. J. Park, C. G. Arges, H. Xu, Y.S. Kim, Membrane Strategies for Water Electrolysis, ACS Energy Letters, 7, 3447-3457 (2022).

S. Adhikari, I. Matanovic, D. Leonard, J. M. Klein, T. Agrawal, Y.S. Kim, Alkyl Ammonium Group Grafted Poly(carbazole)s for Anion Ex-change Membranes, Submitted (2022).
(Invited) Impact of Phenyl Adsorption of Various Ionomers on the Performance of Anion Exchange Membrane Water Electrolyzers
Authors: Klein Jeffrey Michael , Matanovic Ivana , Lehmann Michelle , Saito Tomonori , Kim Yu Seung
Published: September 2023

In this presentation, design principals of ionomeric binders for anion exchange membrane water electrolysis (AEMWE) will be discussed. The crucial impact of phenyl adsorption on AEMWE performance is highlighted with poly(terphenylene), poly(fluorene), poly(aryl piperidinium), or polynorbonene ionomers. Adsorption energies to hydrogen oxidation catalyst surfaces, calculated by density functional theory, demonstrate the utility in the phenyl free ionomer structure wherein lower adsorption energies yield improved AEMWE performance.1,2 Polarization curves with higher adsorption energy ionomers show a nonlinear transition to mass transport limited behavior at cell potentials above 1.68 V. Alternatively, mass transport limitations are absent when using the phenyl free ionomer, polynorbonene.3 Furthermore, polarization curves in 1 M NaOH of all studied systems begin to overlap suggesting that the phenyl oxidation on the oxygen evolution catalyst may be a primary influence on the transition to mass transport limits in AEMWE. Recent progress in both ionomer and AEM development at LANL for improved performance and durability of AEMWE, specifically with regard to limiting phenyl oxidation, will be discussed.

1 Matanovic, I. et al. Adsorption of Polyaromatic Backbone Impacts the Performance of Anion Exchange Membrane Fuel Cells. Chemistry of Materials
31, 4195-4204, doi:10.1021/acs.chemmater.9b01092 (2019).

2 Motz, A. R. et al. Performance and durability of anion exchange membrane water electrolyzers using down-selected polymer electrolytes. Journal of Materials Chemistry A
9, 22670-22683, doi:10.1039/D1TA06869E (2021).

3 Huang, G. et al. Ionomer Optimization for Water Uptake and Swelling in Anion Exchange Membrane Electrolyzer: Oxygen Evolution Electrode. Journal of The Electrochemical Society
167, 164514, doi:10.1149/1945-7111/abcde3 (2020).
Development of Low Iridium Catalyst Layer Structure for a Water Electrolysis Cell
Authors: Yoshinaga Norihiro , Sugano Yoshitsune , Fukazawa Taishi , Ono Akihiko , Nakano Yoshihiko
Published: September 2023

1.Introduction

P2G is viewed as a solution essential for achieving carbon neutrality by 2050. It uses electrolysis to convert electricity from renewables into hydrogen, ready for storage and transportation. The key technology in the process is the water electrolyzer that converts energy into hydrogen without emitting CO2. A PEM water electrolyzer offers excellent adaptability to power fluctuations and high durability. PEM water electrolyzers use membrane electrode assemblies (MEAs) that integrate the electrolyte membrane and electrode. However, the MEA electrode relies on a large amount of iridium to ensure sufficient electrolytic efficiency. Iridium is one of the rarest precious metals and it is four to five times as costlyas platinum. Toshiba has developed a multilayer catalyst that uses a sputtering technology to deposit alternate layers of iridium oxide nanosheet films and void layers, which at low iridium loading achieved a performance superior to that of IrO2 powder anode.

2
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Experimental

The sputtering process was executed in a large chamber that can accommodate electrodes up to a maximum of 5 m2 in size. First, iridium together with pore-forming metal was sputtered onto a commercially available PTL substrate and then only pore-forming metal was sputtered, and this process was repeated to deposit multiple layers. Next, the pore-forming metal was removed to prepare the anode (Fig. 1). The loading of iridium metal was adjusted by the number of iridium layers. Then, a small electrode was cut from a large electrode and a 4 cm2 MEA was made by hot pressing of the anode, Nafion115®, and the Pt/C cathode. A conventional iridium oxide powder layer was sprayed on Nafion115 and a platinum-coated PTL substrate was prepared for reference. Water electrolysis performance of the MEAs was measured in a single-cell configuration by supplying water to the anode side and applying current to the cell under atmospheric pressure.

3
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Results and discussion

Figure 2 shows the water electrolysis IV curves at 80℃ for each type of anode. This novel catalyst structure successfully reduces the iridium to 0.15 mg/cm2, while maintaining the water electrolysis performance and durability. This superior performance is due to the homogeneity of the catalyst layer, which is achieved by a sputtering process enabling nanometer- thick coatings, and the high diffusivity of oxygen and water due to the multilayer structure of the iridium nanosheets and void layers. Our structure also has the advantage of reducing the amount of precious metals by dispensing with the need for Pt coating on the PTL. It was also found that there was no significant variation in water electrolysis performance within a 5 m2 electrode. Thus, the technology for production of large-scale electrodes has been developed. 600 cm2 MEA has also been tested.

Figure 1
Performance of Solvent Substituted Ionomer Dispersions in Catalyst Layer for Hydrogen-Based Energy Conversion Devices
Authors: Park Jong-Hyeok , Heo Jiyoung , Chae Soryong , Park Jin Soo
Published: September 2023

Catalyst inks for the preparation of porous catalyst layer for hydrogen-based energy conversion devices is composed of electrocatalyst, ionomer dispersion and additional solvents. Solvents have an important role in determining the size of ionomer aggregates, the properties of catalyst ink and the morphology of catalyst layer. It has been reported that the solvents for ionomer dispersions substantially influenced the size of ionomer aggregates and finally resulted in the performance and durability. To understand a deep insight into solvent-ionomer molecular interaction, solvation energy obtained by molecular design modeling for a measurement of the relative solubility of ionomers in solvents was studied in this study. In this study, we investigated the solvent-ionomer molecular interaction using molecular design modeling simulation and experimental validation in proton exchange membrane fuel cell and water electrolysis. In addition, I-V polarization curves, cyclic voltammetry and electrochemical impedance spectroscopy were measured and analyzed in terms of solvent property and solvation energy.

Acknowledgment

This research was supported in part by the Hydrogen Energy Innovation Technology Development Program of the National Research Foundation (NRF) funded by the Ministry of Science, ICT & Future Planning(NRF-2019M3E6A1063677) and by the New and Renewable Energy of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20213030040520).
Design Principles for Hydroxide Exchange Membrane Water Electrolyzers
Authors: Tricker Andrew W. , Lee Jason Keonhag , Shin Jason R. , Weber Adam Z. , Peng Xiong
Published: September 2023

Green hydrogen, produced by via water splitting using renewable electricity, will play a crucial role as a renewable energy carrier and in decarbonizing hard-to-decarbonize sectors in the future.1 Hydroxide-exchange-membrane water electrolyzers (HEMWE) have the potential to be more cost effective compared to the incumbent technology, proton-exchange-membrane water electrolyzers (PEMWE), through the use of cheaper catalysts and cell component materials.2 However, HEMWE are at much earlier stage of development compared to PEMWE and, in part, generally operate at lower efficiencies due to a lack of established guiding design and operating principles. Herein, we study how membrane electrode assembly (MEA) component design and cell operating conditions influence the performance of HEMWE. A custom design three-electrode MEA is used to breakdown the overpotential contributions from the anode and cathode, showing that anode OER still dominates the kinetic loss while cathode mass transport limitations is more severe compared to anode. A significant improvement in cell performance is observed for more porous anode porous transport electrode (PTE) compared to dense ones, due to a higher anode catalyst utilization. On the cathode, the use of a hydrophobic gas diffusion layer (GDL) improves performance at high current densities by facilitating the removal of hydrogen gas. The impact of feed configurations including electrolyte fed to both sides, anode fed only, and cathode fed only, on HEMWE performance is thoroughly investigated. In various electrolytes including KOH, KHCO3, K2CO3 and DI water, HEMWEs perform the best with anode fed only, signifying that back diffusion of water through the membrane is sufficient to supply enough reactant to the cathode. These learned principles were used to assemble a completely PGM-free HEMWE that reached 1.6 A cm-2 at 2 V in 1 M KOH, and exhibited stable performance in 0.1 M KOH at 1.5 A cm-2 for over 500 h.

Acknowledgements

This work was funded under the HydroGEN Consortium by the Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office, of the U. S. Department of Energy under contract number DE-AC02-05CH11231.

References

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