bluuebunny/crossref_metadata_2025 huggingface dataset:
(Digital Presentation) Electrocatalytic and Conductive Vanadium Oxide on Carbonized Bacterial Cellulose Aerogel for the Sulfur Cathode in Li-S Batteries
Authors: Lin Xueyan , Wang Shu , Fan Zhaoyang
Published: September 2023

Li-S chemistry is regarded as promising next-generation battery technology. However, its complex redox process and long-chain lithium polysulfides shuttling are hindering the development of practical Li-S battery technology. To address these problems, many transition-metal-oxide-based catalysts have been investigated to chemically bind soluble lithium polysulfides and accelerate their redox kinetics. However, the intrinsic poor electrical conductivities of these oxides restrict their catalytic performance, consequently limiting the sulfur utilization and the rate performance of Li-S batteries. Herein, we report a freestanding electrocatalytic sulfur host consisting of hydrogen-treated VO2 nanoparticles (H-VO2) anchored on nitrogen-doped carbonized bacterial cellulose aerogels (N-CBC). The hydrogen treatment enables the formation and stabilization of the rutile VO2(R) phase with metallic conductivity at room temperature, significantly enhancing its catalytic capability compared to the as-synthesized insulative VO2(M) phase. We characterized the electrocatalytic performance of this unique H-VO2@N-CBC structure using several methods and found that the activation energy between S8 and polysulfides and the one between polysulfides and Li2S are largely reduced by 28.2 and 43.3 kJ/mol, respectively. Accordingly, the Li-S battery performance is greatly improved, with a high initial specific capacity of 1347 mAh g−1 at 0.1 C and remarkable cycling stability with a capacity of 758 mAh g-1 after 300 cycles at 1 C. This work provides an effective strategy for designing and fabricating conductive oxide catalysts to promote the electrochemical performance of Li-S batteries.
(Invited) Iron Flow Battery with Slurry Electrode for Large Scale Energy Storage: Scale-up, Commercialization, and IP Challenges in an Academic Environment
Authors: Savinell Robert F. , Wainright Jesse S. , Sinclair Nicholas Scott
Published: September 2023

Large-scale energy storage is required to meet a multitude of current energy challenges. These challenges include modernizing the grid, incorporating intermittent renewable energy sources (so as to dispatch continuous electrical energy), improving the efficiency of electricity transmission and distribution, and providing flexibility of storage independent of geographical and geological location.

Through efforts supported by ARPA-E and the Department of Energy Office of Electricity, one technology we are developing utilizes an approach based on sustainable, low cost iron electrolytes in an iron flow battery (IFB). Advantages of the IFB include abundant, non-toxic, and non-corrosive materials that are used to provide an energy storage solution that has inherently safe operation and is environmentally friendly. In our approach to the all iron RFB, we introduced a flowing carbon slurry as the negative electrode as a substrate for plating iron during charging allowing storage of the plated iron in a tank external to the stack. This configuration decouples energy and power capacities. The work supported by DOE allowed us to address challenges encountered in scaling up from small laboratory cells to a large commercial size slurry IFB single cell. 1

In this presentation, we will address some of the challenges we encountered for demonstrating the technology within an academic environment in order to position it for commercial development. Even with funding to overcome the valley-of-death and technology-to-market assistance given by ARPA-E, we faced many challenges including hiring expertise to address scale-up, design and testing. We will discuss challenges faced with identifying partners and licensees for moving discovery to product. Also, we will describe the many types of interactions we had with the university Technology Transfer Office including patent disclosure, IP protection, and negotiating licenses.

Acknowledgements: This research was supported by ARPA-E contract DE-AR0000352. Partial support also was received from the DOE Office of Electricity Award #1111358,0 under Dr. Imre Gyuk.

1N.S. Sinclair, R.F. Savinell and J.S. Wainright, MRS Energy & Sustainability, 2022; doi: 10.1557/s43581-022-00046-8
(Invited) How to Identify, Parameterise and Use Complex Electrode Kinetic Models
Authors: Krewer Ulrike , Röse Philipp
Published: September 2023

Electrochemical engineering transfers knowledge from surface/material level to higher levels to build well performing porous electrodes, cells and systems. Modeling accompanies this process at all levels, as it allows for deeper insights into limitations and for subsequent knowledge-driven design and optimization. Modeling tools at higher levels are already well established and predictive, when it comes to heat and mass transfer, as these phenomena are widespread in engineering. They struggle, however, to reproduce or predict the electrochemical behavior of electrodes.

The situation at the electrode level becomes tricky, as there frequently are complex reaction networks at the surface. These lead to a relationship of current, voltage and reactants, which cannot be accurately described by a Tafel- or Butler-Volmer-type rate equation. Identifying suitable reaction network models including reaction kinetic equations and parameterizing them is a challenge; this talk will present promising solutions and their application to selected examples from the electrolysis and battery field.

Besides the electrode surface itself, changes in electrolyte composition close to the electrode surface may occur, which alter electrode performance dramatically. Models may need to account not only for diffusion and migration of the main reactants, but also for transport of intermediates and chemical reactions in the electrolyte as well as phase changes. How can one be sure to have implemented proper processes and parameters? Also here, the talk will give an insight into promising solutions and the application to selected examples including oxygen reduction and CO2 reduction.

The thus identified and parameterized models reveal process limitations and sensitivities which allow for better design and operation of the electrodes. They are further suitable for integration into porous electrode or cell models for design and diagnosis purposes on higher levels.
Electrochemistry of Lead As the Basis of Adoption of Lead Technologies in History
Authors: Fitch Alanah
Published: September 2023

“The goal of the symposium is to draw together the collective interests of scientists and engineers skilled in moving along the path from ideas to profits.” Illustrative of that process at the global level is the use of lead throughout history. The adoption of lead in key technologies is based not only on its ease of corrosion but also on competing political and economic interests. Some of the underlying chemistry and surrounding decision making are of interest and are the subject of this talk. 1) White lead paint and (2) sugar of lead were adopted in the Roman Empire due to the ease of corrosion of lead and continued, in the case of paint, into the 1970s. 3) One theory for the fall of the Roman Empire is due to lead intake, in part, from lead water pipes. This theory will be briefly examined in the context of other lead uses. 4) The politics, science, and, then current understanding of lead health issues, were debated at the time of widespread adoption of lead piping (1850s) as will be explored up and to current politics in Flint and current epicenter of lead pipe issues (Chicago). 5) Lead acid batteries were the leading propulsion choice for vehicles in the 1890s. How money shaped the race between lead acid battery and gasoline powered vehicles is explained. An understanding of these competing interests and alternative technologies may inform challenges of adoption of technology today.
Pulsed Rapid Thermal Annealing as a Low Thermal Budget Semiconductor Fabrication Process
Authors: Kuo Yue
Published: September 2023

Thermal annealing is required in the fabrication of many semiconductor devices. A proper annealing condition, e.g., temperature, atmosphere, and time, can improve the device performance, e.g., by reducing defect densities in bulk films and at interfaces. In addition, the annealing step can generate new structures in previously deposited thin films for various new functions. However, when the annealing condition is improper, e.g., the temperature is too high or the annealing time is too long, the device performance can deteriorate or dysfunction due to damage to the composing material, structure, or even the substrate. The thermal budget is critical in the thermal annealing step.

Pulsed rapid thermal annealing (PRTA), which exposes the sample to repeated cycles of short-period heating and cooling, is a low thermal budget process. In this presentation, the principle of PRTA is presented. Examples of using PRTA in the crystallization of amorphous silicon on the glass substrate to polycrystalline thin films for thin film transistors (TFTs) and solar cells, improving high-k gate dielectric properties for MOS capacitors and solid state incandescent light emitting devices (SSI-LEDs), and preparation of nanocrystals embedded high-k structure for nonvolatile memories will be shown (1-4). Limitations of PRTA and possible improvements will be discussed.

Kuo and P. M. Kozlowski, Appl. Phys. Lett., 69(8), 1092-1094 (1996).

Kuo, C.-H. Lin, and M. Zhu, IEEE Photovoltaic Specialist Conf.
PVSC 35, 3698-3701 (2010).

Y. Kuo and C. H. Lin, ECS 237th Meeting Abstract # 130648, May 10-15, 2020.

Y. Kuo, ECS 227th Meeting Abstract # 47306 (1333), May 24-28, 2015.
Elucidating Dynamic Conductive State Changes in Amorphous LLTO for Resistive Switching Devices
Authors: Shimizu Ryosuke , Cheng Diyi , Zhang Minghao , Meng Ying Shirley
Published: September 2023

Resistive random-access memory (ReRAM) is one of the promising memory devices to achieve neuromorphic computing that is a novel system to mimic human brain. ReRAM has a simple metal-insulator-metal structure and has advantages such as low power consumption and low manufacturing cost. Recently, our group has developed amorphous lithium lanthanum titanate (Li3xLa2/3-xTiO3, LLTO) thin film as a solid-state electrolyte for all solid-state thin-film batteries by using pulsed laser deposition, which has high ionic conductivity (≈10-3 S/cm) [1]. Beyond its application to energy storage devices, we found that the amorphous LLTO (a-LLTO) demonstrates a resistive switching response under the stimuli of an external electric field, where LLTO becomes high resistance state (HRS) at pristine state and switches to low resistance state (LRS) by external electric field. However, despite its unique feature, the resistive switching mechanism of a-LLTO is poorly understood.

Thus, in this work, we demonstrate successful observation of LLTO resistive switching behavior and optimize voltage range to achieve both resistive switching and cycling stability. Furthermore, electronic conductivity changes that provoke the LLTO switching are investigated through the comparison of thin films with different oxygen composition, under an hypothesis that oxygen vacancy plays a role in changing local LLTO conductivity. First-principles analysis also supports such conductivity change mechanism due to the local composition changes under electrical bias. Based on these experimental and computational results, the switching mechanisms are discussed with a simplified LLTO model. At last, in-situ testing of LLTO nano device under focused ion beam (FIB) setup, which aims for scanning transmission electron microscopy (STEM)-electron energy loss spectroscopy (EELS) to fully elucidate the switching mechanisms of LLTO at nanoscale.

Reference

[1] Lee, J. Z.; Wang, Z.; Xin, H. L.; Wynn, T. A.; Meng, Y. S. Amorphous Lithium Lanthanum Titanate for Solid-State Microbatteries. J. Electrochem. Soc. 2016, 164 (1), A6268.

Figure 1
(Invited) Application of Synchrotron X-Ray Topography Techniques to the Analysis of Defect Microstructures in Bulk GaN Substrates and Epilayers for Power Devices
Authors: Liu Yafei , Hu Shanshan , Chen Zeyu , Cheng Qianyu , Raghothamachar Balaji , Dudley Michael
Published: September 2023

Wide bandgap semiconductor gallium nitride (GaN), along with silicon carbide (SiC) are replacing silicon materials in the applications for power electronic devices. While SiC-based power technologies are based on bulk SiC substrates, GaN-based power technologies have until recently been based on GaN layers grown on foreign substrates such as sapphire, SiC and Si substrates. To achieve the full potential of GaN power devices, devices on bulk GaN substrates are desirable. In this review, the use of synchrotron X-ray topography techniques to evaluate defects and strain in bulk GaN substrates for vertical device development is presented. Ray tracing simulations is shown to effectively identify the Burgers vectors of all dislocations on X-ray topographs from GaN materials. Ammonothermal-grown GaN substrate wafers show the best quality among all the wafers. These wafers, which are free of basal plane dislocations (BPDs), have low curvature and threading mixed dislocations (TMDs) dominant among the TDs. However, certain ammonothermal substrates contain growth sectors with different impurity concentrations that are likely inherited from prior seed expansion growth runs. Patterned hydride vapor phase epitaxy (HVPE) GaN reveal a starkly heterogeneous distribution of dislocations with large areas containing low threading dislocation densities in between a grid of strain centers with higher threading dislocation densities and BPDs. These substrates also contain growth sector boundaries separating core regions growing in <11-22> directions and surrounding regions growing along [0001]. HVPE GaN substrates are characterized by high lattice distortion and dislocation densities of the order of 105-106 cm-2, which is much higher than 103-104 cm-2 of ammonothermal samples and dislocation-free areas in the patterned HVPE samples. Epitaxial growth and other processes involving heat treatment (including annealing) does not nucleate new defects but can result in interactions of dislocations (threading screw dislocations(TSDs)/threading mixed dislocations (TMDs)/threading edge dislocations (TEDs)) with point defects leading to changes in dislocation configurations. Mg-ion implantation for p-type doping does not change the distribution of dislocation but introduces lattice damage. By Rocking curve Analysis by Dynamical Simulation (RADS) analysis of X-ray rocking curves, the depth profile of strain can be obtained and correlated with doping profile. During annealing the implanted samples to heal lattice damage and activate the Mg ions, proper capping is necessary to limit loss of matter and introduction of additional lattice distortion. However, high pressure annealing has been shown to eliminate the need for capping. The effect on microstructure from other selectively area doping techniques such as etch and regrowth, diffusion and neutron transmutation will also be discussed.
(Invited) highly Stretchable Self-Powered Sensors Enabled By Vertically-Assembled 2D Materials
Authors: Lee Yeageun , Nam SungWoo
Published: September 2023

Future electronics, such as human health monitoring systems, require highly stretchable strain sensors applicable to various types and ranges of motions. Two-dimensional (2D) materials exhibiting superior mechanical properties have a potential to achieve high range of strain compared to conventional devices and also realize self-powered sensing. In this talk, we present self-powered strain sensor with large stretchability enabled by graphene electrode layers and molybdenum disulfide (MoS2) active layer. In order to maximize the energy harvesting ability, flexoelectric effect was adopted in our device design. Flexoelectric effect induces an electric polarization from strain gradient, and the size of the strain gradient grows quadratically as the material’s length scale decreases. This scaling enables maximum flexoelectric effects in 2D materials with strain gradient. To realize the strain gradient in MoS2 active layer, we first prepared graphene-MoS2 vertical stack on a pre-stretched elastomeric substrate followed by a release of the stretch to create a crumpled heterostructure. The crumpled MoS2/graphene was again stretched to a smaller strain, and the other graphene electrode layer was placed on top of the crumpled MoS2 active layer. Releasing the strain after assembly resulted in a periodic contact between the top graphene electrode and the MoS2 active layer while maintaining a full contact between the bottom graphene electrode and the MoS2 active layer. Our stretchable flexoelectric graphene/MoS2/graphene device demonstrated voltage and current outputs under various mechanical deformations, including bending and stretch-release motions. Our results demonstrate self-powered strain sensing capability under high degree of bending and stretching motions, potentially applicable to human health monitoring sensors.
(Invited) emerging Designs for Organic Infrared Photodetectors and Energy Storage
Authors: Ng Tse Nga
Published: September 2023

The shortwave infrared spectral region (SWIR: 1-3 mm) is particularly powerful for health and environmental monitoring, enabling greater penetration depth and improved resolution in comparison to visible light. However, conventional SWIR sensors are limited by complex die transfer and bonding processing. This presentation will discuss the advances made in organic infrared detectors to overcome the issues in conventional SWIR detectors. The organic devices show photo-response spanning from the visible to 1.7 micron, using a new generation of semiconducting polymers that are processed by solution processing techniques and allow simple direct deposition. We will discuss the recent progress in identifying avenues that will improve sensor detector, such as understanding the origin of efficiency losses and materials optimization. Several demonstrations will show the various potential applications of organic infrared imagers, particularly for an up-conversion structure that combine photo-sensing and display in a compact structure without the need for pixilation. The imaging active area of 2 cm2 enabled concurrent recording of blood vessel location and blood flow pulses.

In addition to visualisation of infrared radiation, we are also developing the integration of redox polymers into supercapacitor structures to serve as energy supplies for wireless electronics. A new Faradaic electrode material comprised of a narrow bandgap donor−acceptor conjugated enhanced charge delocalization and thus improved stability dramatically. The supercapacitors were patterned by electrodeposition and showed a high areal power density of 227 mW/cm2, enabling rapid charging and high power output. The capacitance retention was 84% after 11,000 full redox cycles, offering the critical benefit of long cycle life. This work demonstrated the application of a new class of stable redox-active materials suitable to meet the energy storage needs for short-range wireless electronics.
(Invited) smart Wearable Electronics for Chronic Disease Management
Authors: Niu Simiao
Published: September 2023

60% of Americans live with at least one chronic disease. These diseases and associated comorbidities are now the leading causes of death in the United States. Effective management of complex chronic diseases requires body-wide, long-term, accurate, and continuous monitoring of multiple physiological signals from wearable devices to precisely determine the pathological state. These wearable physiological signal monitoring can dramatically reduce the demand of physician visiting and increase patients’ engagement and treatment adherence rate. Although wearable bioelectronic devices have shown huge potential in chronic disease management, existing technology still mostly relies on rigid chip components, where the interface between chips and skin/tissue has been a bottleneck that limits the system performance (noise, robustness etc). To address these challenges, my research has been involved in the exploration of rational system design concepts, material and device fabrication innovation, and tailored algorithms to enable smart wearable electronics that targets next-generation chronic disease management.

Here I would like to discuss two of my developed technology platforms to elaborate the concept of smart wearables. First, I will describe a body area sensor network technology platform. In the system design concept side, this technology utilizes a novel wireless hybridization strategy and an unconventional detuned RFID working regime that provide an ideal skin interface. In the material/device side, this system integrates several skin-conforming polymer-based soft devices (ring oscillators, RF diodes, antennas, transistors etc.) as an integrated soft multimode sensing sticker. (1,2) Next, I will describe a wireless closed-loop smart bandage that can accelerate and monitor the wound healing process. (3) Such smart bandage also integrates new design concepts (wireless, battery-free design that combines both sensing and stimulation), novel materials (low-impedance, high-toughness, and tunable adhesion hydrogel as skin interface) and closed-loop control algorithms. Overall, the developed technology platform could assess multiple health outcomes and treatment responses to various chronic diseases. Ultimately, this technology will help to reduce chronic disease burden, lower medical costs, and provide a better quality of life for patients.

References:

1. “A Wireless Body Area Sensor Network System Based on Stretchable Passive Tags”. Nature Electronics 2019, 2, 361.

2. “High-Frequency and Intrinsically Stretchable Polymer Diodes”. Nature 2021, 600, 246-252.

3. “Wireless, closed-loop, smart bandage with integrated sensors and stimulators for advanced wound care and accelerated healing”. Nature Biotechnology 2022, DOI: 10.1038/s41587-022-01528-3.
A Microfluidic Flow Sensor Based on CuO Nws Enhanced Solid-Liquid Contact Electrification for Trapping Platelets on Collagen and Its Quantification
Authors: Kaswan Kuldeep , Lin Jia -Cheng , Ganguly Anindita , Chatterjee Subhodeep , Fan Yu-Jui , Lin Zong-Hong
Published: September 2023

Platelet number plays an important role in several kinds of diseases such as leukemia, hepatitis C, diabetes, COVID-19, microbial infections, etc. These diseases can result in thrombocytopenia, a condition where patients suffer from reduced platelets, thus requiring the need to frequently monitor the platelet count. Currently existing techniques are complex, costly, and time consuming. The target diseases continue to evolve urging the need to develop rapid, facile point-of-care devices with high precision. In this regard, the current study is focused on the development of a platelet quantification technique based on trapping of platelets in a microfluidic channel adhered with collagen layer, and CuO NWs grown on Cu tube integrated on both the sides of the channel. This trapping of platelets results in a change in the triboelectric output performance from solid-liquid contact electrification due to change in flow rate of platelet content in the plasma. These changes in triboelectric output are enhanced by CuO NWs due to its high surface-area-to-volume ratio. The study of flow sensing by integrating the microfluidic device with solid-liquid contact electrification has been reported for the first time. The flow sensing signal was optimized by variation in viscosity of the flowing liquid, channel geometry, flow rate, and triboelectric voltage measuring methods. The platelet rich plasma (PRP) and platelet poor plasma (PPP) were prepared and mixed in different ratios to prepare the solutions with different concentration of platelets (0% - 100%). The calibration curve for platelet quantification has shown a variation of 9 V for change in platelet concentration from 0% to 100%. The proposed device exhibited a linear response with the variation in platelet counts. The obtained results prove its potential and feasibility as a point-of-care device.
(Invited) ultrasensitive Low Cost Flexible Sensors and Bioinspired Sutureless Anastomosis Devices
Authors: Kang Sung Hoon
Published: September 2023

I will present our efforts for investigating flexible electronic sensors for potential health monitoring applications and bioinspired sutureless anastomosis devices for easier, faster, and safer surgery.

Highly sensitive flexible tactile sensors are of continuing interest for various applications including human–machine interface systems, internet of things, and wearable health monitoring devices. Current technologies for high sensitivity piezoresistive sensors tend to rely on costly materials and/or fabrication methods, limiting accessibility and scalability. Here, we report a facile sacrificial casting–etching method to synthesize nanoporous carbon nanotube/polymer composites for ultra-sensitive and low-cost piezoresistive pressure sensors. Our synthesis method overcomes the limitations of the traditional solution-dip-coating method for adhering nanoscale conductive materials to the nanoscale porous surface. Importantly, we show ultra-high sensitivity with a strain gauge factor over 300, which is ∼50 times higher than that of traditional CNT-based piezoresistive sensors. For practical tactile sensing applications, we demonstrate that the sensors can detect both gentle pressures (1 Pa–1 kPa) and low pressures (1 kPa–25 kPa) with a fraction of the cost. Our nanoporous polymer composite could contribute to expanding the scope of using nanocomposite sensors for medical applications from its easy tunability for sensing diverse range of tactile signals.

Anastomosis, the surgical connection of adjacent tubular organs is a foundational surgical skill for many surgical procedures. The current standard of anastomosis is manually suturing two tubular structures together around an opening with fine sutures. However, it requires several years of surgical training, a long time (60 to 90 minutes per anastomosis) for procedure, and, at times, specialized equipment, facility and staffs. Thus, it is an expensive (up to $35,000 per procedure).Moreover, even in the hands of skilled surgeons, the anastomosis can be complicated by leakage or thrombosis. To address current challenges, we investigated a sutureless anastomosis device inspired by rose prickles. I will present our approach to design, fabricate, and test devices. Our device showed the failure force comparable to that of the handsewn suture (4.9 N) and no leakage up to 45 mL/min flow rate, well above the physiologic blood flow rate. Compared with handsewn anastomosis, the device resulted in minimum deformation of the anastomotic site. From in-vivo non-survival porcine studies, the device showed successful anastomosis (< 5 min per anastomosis) with no leaking for both arterial and venous anastomoses. We envision our findings can contribute to enabling easier, faster, and safer anastomosis, and making anastomotic techniques more accessible to a broad range of clinicians, researchers, and patients across the world.
(Invited) triboelectric Nanogenerator Based Sensors for Water Quality Evaluation
Authors: Pradel Ken , Urano Toshiyuki , Mizukami Junji
Published: September 2023

Clean water is a necessary component for all life. Unfortunately, in many countries, both developed and not, clean water is not a guarantee. Because of that, there has been a growing market for personal water quality sensors and tools. This ranges from electronic meters to determine pH and salinity, to reagent strips for heavy metals such as lead and mercury. Each of these methods has its strengths and weaknesses, and in our search for new technology to compete with this, have been investigating the principle of triboelectrification as one possibility. When objects of different work functions are placed in contact, there is a charge transfer that occurs. When hooked up to an external load, and cyclically contacted and released, this can be harnessed for power generation in the form of triboelectric nanogenerators (TENG) or nanosensors (TENS). While the technology began with contacting solid objects, it was soon discovered that the principle also applies to interactions between solids and liquids.

We have begun investigations on constructing triboelectric sensors for detecting small amounts of contaminants in water. By chemically modifying a copper wire, we can detect concentrations of contaminants such as acetone at concentrations as low as 5% per volume, while avoiding false positives from similar compounds like ethanol. We were also able to measure ammonia in water at similar concentrations. The coating preferentially binds to the target molecule, changing the work function, which in turn changes the output voltage. A Dobot Magician robot arm is used to help produce more consistent and reproducible signals. In the future, we will continue pushing this technology to detect other common contaminants, while miniaturizing the robotics and computer systems for collecting and processing the data, respectively.

Figure 1
Self-Powered Robotic Sensor for Remote and Real-Time Monitoring of Heavy Metal Ions
Authors: Huang Yan-Tsz , Lee Kuan-Ming , Lin Zong-Hong
Published: September 2023

In the recent years, heavy metal pollution has tremendously increased worldwide due to natural as well as anthropogenic reasons. Heavy metals accumulate in the human body through drinking water and food, ultimately causing irreversible damage to the body. For most of the heavy metals, the World Health Organization (WHO) has set permissible limits from 0.003-3 ppm in drinking water, above which it is contaminated. In addition, chemical threats remain a major global concern for sampling and sensing factors in unsafe environments. Therefore, robotic hand-based chemical sensing platforms that can monitor hazardous pollutants in the real environment are essential. Although robotic hand-based chemical sensors show great potential to substantially prevent humans from chemical threats in the environment, applications are often limited by the requirement of high-power consumption. In this study, we have fabricated a self-powered triboelectric nanosensor, which is integrated with a robot platform with wireless transmission capability, to detect heavy metal ions in the environment through a rapid onsite detection mechanism. In this regard, a copper electrode modified by an ion selective membrane (ISM) is used as a solid triboelectric material and is integrated with a robotic hand. Since the ionophore selectively binds to the corresponding ions, the solid-liquid TENS could detect Cr6+, Pb2+, and As3+ ions at a wide range of concentrations by the periodic contact and separate motion of the sensor probe to lead (Pb2+), arsenic (As3+) and chromium (Cr6+) solutions. This realization of direct integration of self-powered sensors with robotics provides low-cost and automated chemical sensing mechanisms. It can be applied to various environments for on-site detection of hazardous analytes and security. Finally, a real time remote monitoring system allows the presentation of the environmental monitoring data on mobile devices and enables remote real-time monitoring of the hazardous pollutants.
High Purity Hydrogen and Carbon Dioxide Separation with Electrochemical Pump Operation of HT-PBI Fuel Cell at 120°C
Authors: Maxwell Derrick , Sun Qiang , Rojas Humberto , Kendrick Ian , Pavlicek Ryan , De Castro Emory , Aurora Akarsh , Mukerjee Sanjeev
Published: September 2023

A commercially available, polybenzimidazole (PBI) membrane based electrochemical hydrogen pump (EHP) platform was thoroughly evaluated to generate a benchmark set of performance. A primary gas mixture of CO2 and H2 with a ratio of 4:1 was selected to demonstrate the performance of EHPs while addressing concerns of CO2 poisoning effect. There is no indication of significant CO poisoning as a result of reverse water gas shift reaction (RWGS), and nearly Faradaic current efficiencies were successfully achieved. It was found that humidification of the feed gas at room temperature improved polarization performance while also improving energy efficiency, thus reducing the need for tightly controlled relative humidity of feed gas. A new perspective on EHP energy efficiency calculation methodology is also provided by inclusion of the cell heating requirement into the calculation. In this manner, an overall improvement to energy efficiency nearing 20% was realized by dropping the cell temperature to 120°C while paying no significant penalty to electrochemical performance. Nearly 99.99% pure H2 and 99.93% pure CO2 were produced with a hydrogen yield of 99.34%.
Examining the Upstream Renewable Energy Source Variability on PEM Water Electrolyzer Behavior
Authors: Ayyaswamy Abhinand , Goswami Navneet , Vishnugopi Bairav Sabarish , Mukherjee Partha P.
Published: September 2023

Hydrogen bears a unique prospect to decarbonize sectors like electricity, transportation, manufacturing, and construction simultaneously in an economical path toward mitigating global warming. A proton-exchange membrane water electrolyzer (PEMWE) coupled with an upstream variable renewable energy (VRE) source is a promising candidate for green hydrogen production. However, the seasonal variation and uncertainties in available power from upstream VREs vary geographically and diurnally, posing various challenges to the operational limits of PEMWEs. It is imperative to understand the stochastic variability in energy sources and operating conditions for maximum throughput through electrolysis, to provide a long-term energy storage with hydrogen. Energy storage systems with regenerative hydrogen fuel cells are prime candidates to reduce VRE curtailment in power grids because of greater energy storage on investment than lithium-ion batteries. In this work, we investigate the geospatial and seasonal variation of upstream energy supply to PEMWEs and delineate region-specific design considerations through a mechanistic modeling framework. The varied implications of the microstructural design space allow us to evaluate a balance between target hydrogen cost whilst alleviating VRE curtailment and accommodating variance in energy supply.
An Integrated Analytics of PEM Electrolyzer and Steel Making
Authors: Goswami Navneet , Ayyaswamy Abhinand , Vishnugopi Bairav Sabarish , Ciez Rebecca , Mukherjee Partha P.
Published: September 2023

It is widely accepted that the hydrogen-water couple can elevate the green economy circuit if powered by renewable sources of energy. Proton-exchange membrane water electrolyzer (PEMWE) being a clean electrochemical device is expected to provide an amenable solution to the hydrogen-water nexus and act as an enabler to achieving decarbonization of the steel-making industry. In this work, we throw light on the performance of a PEMWE that feeds target hydrogen volumes to a direct iron ore reduction process. The response of the electrolyzer under the presence of a host of operational stressors and variable electricity input is delineated through a macroscale modeling framework. The techno-economics associated with specific energy consumption of the downstream steel-making pathways will be further discussed based on insights from a process cost model.
Ionic Decoupling in PEM Water Electrolyzers and Cost-Effective Cell Components
Authors: Proch Sebastian Karl , Bexell Ulf , Westlinder Jörgen
Published: September 2023

Potential profiles through the PEM water electrolyzer anode compartment have been found to be highly dependent on feedwater resistivity (see Figure 1). Typical type II industrial feedwater leads to a considerable drop in local potential from the anode catalyst layer (> 1.5 V vs. RHE) to the bipolar plate (1.0 V vs. RHE). At such a potential, cost-effective materials like stainless steel and carbon are stable [1] which expands their use case from PEM fuel cells to PEM water electrolyzers. Moreover, the potential profiles suggest substituting most of the PTL by more cost-effective materials than titanium, e.g., stainless steel [1].

[1] H. Becker et al. Assessing potential profiles in water electrolysers to minimize titanium use,
Energ. Environmental Sci
. 2022, 15, 2508-2518.

Figure 1
(Invited) Single Cell Voltages for Safety, Predictive Maintenance, and Process Optimization of Industrial Scale Bipolar Electrolyzers (Learned Lessons From Over 30 Years Experience in Chlor-Alkali-Electrolysis)
Authors: Lademann Helmut , Tremblay Gilles , Simard Georges , Dubois Jacques , Berriah Said
Published: September 2023

Just like the membrane electrolysis process in the Chlor-Alkali industry 30 years ago, water electrolysis is facing a major transformation from a niche technology to become a global commodity business. 30 years ago, the unique risks of big bipolar electrolyzers were not recognized by the industry. Lessons learned from incidents and near misses led R2 to the development of the EMOS® Safety System: the state-of-the-art single cell voltage-based safety instrumented system for bipolar electrolyzers. Today, the EMOS® Safety System has become a standard in the Chlor-Alkali industry. With plans announced for much larger electrolyzers and several times higher current densities and their increasing risks, water electrolysis should be spared this painful learning process. Fortunately, EMOS® Safety System supports also bipolar water electrolyzers. Short circuits, separator failures etc. can be only detected with single cell current-voltage-curves to turn the power supply off before explosive gas reaches areas with dangerous high gas holdup.

Same time the single cell voltages are used to detect any abnormal cell aging as early as possible and to correlate it with the operating conditions. For this purpose, automatically during the electrolyzer startup a neural network is trained to predict the cell voltages afterwards in real-time and to alarm already a deviation of a few mV from the measured cell voltage. Together with KPI’s like U0 and k, automatically calculated by analyzing load changes from normal electrolyzer operation for each cell, predictive maintenance, cell performance specific replacement and process optimization is possible, customized for the individual industrial plant.

Examples from industrial scale electrolyzers concerning safety, maintenance and performance optimization will be presented.
Mathematical Modeling of the Performance-Degradation Mechanisms of Cation-Contaminated Proton-Exchange-Membrane Water Electrolysis
Authors: Dizon Arthur , Padgett Elliot , Adesso Anthony , Wrubel Jacob A , Mukundan Rangachary , Pivovar Bryan S. , Alia Shaun M , Weber Adam Z.
Published: September 2023

The role of hydrogen as a commercial energy carrier is dependent on the development of robust processes to convert hydrogen into usable electricity as well as produce hydrogen at large scales. Proton-exchange-membrane water electrolysis (PEMWE) is a leading technology with the potential to produce hydrogen at projected consumption rates. In PEMWE, water is electrochemically split into hydrogen and oxygen gas using a membrane—electrode assembly, which uses a membrane capable of transporting both water and protons. Reactant water containing cationic impurities have been observed to degrade cell performance. Thus, developing an understanding of the influence of cationic contaminants is important to developing mitigation and recovery strategies for PEMWE systems.

In the current work, mathematical models were developed to provide insight into the mechanisms of performance degradation due to cationic contaminants. The models are non-isothermal continuum models that describe multi-phase porous flow, electrochemical reactions, and concentrated-species transport in both the gas membrane, and ionomer phases. Simulations were performed in steady-state and transient operational modes for various cationic species at several ionic concentrations. The calibration and fitting of the models were performed using experimental measurements performed by the National Renewable Energy Laboratory. The mathematical models suggest that gradients facilitate the adsorption of cationic contaminants in reactant water, which subsequently accumulate in the cathode catalyst layer, as shown in Figure 1(a), and inhibit the PEMWE hydrogen-evolution reaction (HER) that consume protons and electrons to produce hydrogen gas. The models suggest that protonic conductivity is not significantly affected by low-concentration cationic species, but access to the catalyst active sites in the cathode catalyst layer is severely impeded. As a result, the evolution of hydrogen then proceeds by an alkaline mechanism, where water and electrons combine to produce hydrogen gas and hydroxide ions. An interpolated polarization curve shown in Figure 1(b) suggests that cell operation at high current densities favor the alkaline HER reaction due to the lack of protons in the cathode catalyst layer.

This research is supported by DOE Hydrogen and Fuel Cell Technologies Office, through the H2NEW Consortia.

Figure 1
(Invited) Understanding Oxygen Transport in Polymer Electrolyte Membrane Water Electrolyzers Using X-Ray Computed Tomography
Authors: Zenyuk Iryna , Chang Hung-Ming , Parkinson Dilworth Y. , Karatay Elif , Danilovic Nemanja
Published: September 2023

This study aims to understand the fundamental processes that affect catalyst utilization and gas transport through the porous media in polymer electrolyte water electrolyzers (PEWEs) to optimize porous transport layers (PTLs) and flow-fields. We designed a novel operando x-ray computed tomography (CT) cell that can resolve oxygen transport along a 10 cm x 1 cm membrane electrode assembly (MEA) active area. The flow field with two straight channels was designed for this operando cell. X-ray CT with the field of view (FOV) of about 3 mm x 2 mm and resolution of 0.7 um allowed visualizing MEA and flow channels of operando PEWEs. The cell features three observation windows that are transparent to x-rays. These are located near the inlet, in the middle of the flow-channels and at the outlet. In addition, thermocouples are embedded in various locations in the cell to measure temperature profiles of the cell. Oxygen content in the flow-channels was observed for various current densities using 2D radiography technique, with 5 ms time resolution step size. The cell morphology and steady-state oxygen distribution in the PTL were observed using stained water (stained with NaI). The results show significant oxygen enrichment in the channels near the outlet, as well as higher oxygen presence in the PTLs near the outlet. This new cell design can enable simultaneous heat and mass transport measurements along the flow channels. Inlet-outlet variations in oxygen content at scale of 10 cm is of relevant to single cell testing in the laboratory.
Alkaline-Stable Anion Conducting Ionomers for Anion Exchange Membrane Water Electrolyzers
Authors: Akter Mahamuda , Shin Jiyun , Park Jong-Hyeok , Chae Soryong , Park Jin Soo
Published: September 2023

Water electrolysis is a process that uses renewable energy to decompose water into oxygen and hydrogen. It is one of the most promising alternatives to produce and store new energy from renewable energy resources. In this study, pore-filled anion exchange membranes (PFAEMs) were prepared by using quaternary ammonia groups along with various cross-linker groups with different chain lengths and using porous polyethylene substrates which were pretreated from hydrophobic into hydrophilic using surfactants. The conductivity of the anion exchange membranes was measured by the in-plane cell and through-plane at room temperature or 60 ℃. In addition, the characterizations of anion exchange membranes such as water uptake, swelling ratio, mechanical strength, contact angle and TGA were carried out. As a result, the PFAEM exhibited remarkably high ion conductivity at extremely low areal swelling ratio and excellent chemical stability in a NaOH solution for 500 h. As an essential component of anion exchange membrane water electrolyzers, catalyst layers prepared by the catalyst inks comprising of ionomer binder and electrocatalysts are sandwiched between the anion exchange membrane to form a membrane electrode assembly in order to evaluate its impedance and I-V polarization curves.

Acknowledgment

This research was supported in part 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) and by 2021 Green Convergence Professional Manpower Training Program of the Korea Environmental Industry and Technology Institute funded by the Ministry of Environment.
A New Semi-Empirical Method of Quantifying Electrolyzer Degradation
Authors: Errico Shaina Brianne , Fortiner Serafina , Kulkarni Devashish , Motz Andrew R
Published: September 2023

Electrolyzers are a key component in transitioning the world’s reliance on fossil fuels for energy. Accordingly, a substantial influence on electrolyzer costs is operational efficiency. The means of quantifying this efficiency is necessary for sustaining the continuous improvement of this technology.

Polarization curves are a critical tool in understanding the behavior and mechanisms of electrochemical devices such as electrolyzers and fuel cells. In this work, a semi-empirical voltage-breakdown method is used to model and identify a series of resistance levels and voltage losses. This model presents the modes of change in electrolyzer performance. Polarization curves are taken at several temperature and time intervals throughout steady state operation. The unique benefit of this method is that no potentiostat is required and that key parameters, such as the Tafel slope and ohmic resistance, are compared to more direct measurements.

Presented here, is a user-friendly technique of evaluating the degradation of an electrolyzer over the course of its lifetime. More specifically, it provides insight on the durability of cell components such as membrane, gas diffusion layers, and catalyst layers.
Imidazolium-Based Anion Exchange Membranes for Electrochemically Converted Liquid Organic Hydrogen Carrier
Authors: Lee Minyoung , Jeong Dahye , Shin Jiyun , Akter Mahamuda , Park Jong-Hyeok , Chae Soryong , Park Jin Soo
Published: September 2023

Liquid organic hydrogen carrier (LOHC) is a technology that uses renewable energy for hydrogen transportation, storage and utilization. LOHC have advantages that can store and utilize hydrogen rapidly in the lack of transportation infrastructure. A membrane-based LOHC system is a promising technology due to the dynamic operation using electrochemistry. Anion exchange membranes are widely used as electrolyte for electrochemical devices. The performance of LOHC could be determined by the properties of anion exchange membranes. Thus, high anion conducting ionomers must be developed for the superior conversion rates on the electrochemical reduction of liquid toluene to methylcyclohexane. In this study, anion exchangeable polymers containing imidazolium salt as anion-conducting group were synthesized to achieve good conduction of hydroxide ions and their chemical stability. Anion exchange membranes were prepared by a pore-filling method using porous polyethylene substrate. The pore-filling anion exchange membranes were characterized in terms of ion conductivity, areal resistance, ion exchange capacity, water uptake, swelling ratio and mechanical strength.

Acknowledgment

This research was supported in part by the Korea Institute of Science and Technology (No. 2E31871) and by 2021 Green Convergence Professional Manpower Training Program of the Korea Environmental Industry and Technology Institute funded by the Ministry of Environment.