bluuebunny/crossref_metadata_2025 huggingface dataset:
Prediction of Coexisting Gases By Deep Neural Networks
Authors: Hwang Yun Ji , Hwang Teajong , Hong Jongwoo , Jun Seong Chan
Published: December 2024

The air we breathe contains many different types of gas molecules. Depending on the type, some gases may be essential to human life, while others may be harmful. Predicting the presence of gases is necessary for various purposes, such as preventing disease, finding the source of environmental problems, and reducing harmful substances. In addition, since several gases are usually present in the air at the same time, a technique for identifying gas species is essential. In this study, we use two-dimensional materials to verify their interaction performance with gas molecules and design a deep learning model to predict the coexisting state of gases. Taking advantage of the fact that two-dimensional materials such as graphene and MXene adsorb or desorb with gas molecules and change their electrical properties by electron transfer, we design a sensor that can detect multiple gases simultaneously and obtain resistance data. The algorithm developed in this study preprocesses the resistivity data and fits it to a deep neural network model. The performance of the deep neural networks designed with a simple structure was evaluated among the models, and the final model obtained showed an excellent prediction rate of more than 90%. The two-dimensional material selected as the gas-sensitive material in this study can be deposited similar to a plane, so the sensor can be miniaturized and is useful for use as a device. In addition, by predicting the coexisting state of gases in combination with deep learning technology, it can be developed into a real-time diagnosis of gases, and can be used in a wide range of fields such as biology and environmental management technology.
Early Sensing of Hazardous Volatile Organic Compounds to Avoid Disastrous Li-Ion Battery Thermal Runaway
Authors: Pol Vilas G. , Kaur Palwinder , Bhondekar Amol , Bagchi Sudeshna
Published: December 2024

Worldwide, lithium-ion batteries (LIBs) applications are growing from kWh (electric vehicle) to GWh (grid storage). Along with LIBs proliferation, the complexities in giga factory level battery manufacturing, large-scale storage, system installations and safe DoD operations became significant with enhanced probabilities to mechanical, electrical, or thermal abuse conditions. Thermal runaway,1 a potential hazard leading to battery failure and even fire and explosions, demands innovative solutions for early detection to prevent catastrophic incidents.

Purdue University’s Vilas Pol Energy Research (ViPER) research team innovated scalable, cost effective, and energy efficient polymeric sensor2 for the early detection of volatile organic compounds (VOCs) and various gases released before catastrophic thermal runaway through measuring increased impedance in the LIBs. The studied impedimetric chemosensing of VOCs and vented gases coupled with the battery management system (BMS) is capable of early warning through real time data analysis to the driver/operator, public, fire fighters and first responders on expected toxic and combustible gases.

For the proof of concept, submicron (∼0.15 μm) thick poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) sensor film was coated on an interdigitated platinum electrode measuring VOCs at 5, 15, and 30 ppm independently, in various combinations and at different temperatures with DC resistance/impedance spectroscopy.3-5 These preliminary research and development activities (TRL 2) demonstrated that the initial generation of VOCs before final thermal runaway of the cells can be tracked in seconds mitigating catastrophic event from occurring by sudden cooling of the entire system or venting the storage area. The obtained detection results will be discussed with the technology that could avoid LIBs thermal runaway in the field environment.

References

W. Huang, X. Feng, Y. Pan, C. Jin, J. Sun, J. Yao, H. Wang, C. Xu, F. Jiang and M. Ouyang, J. Energy Storage, 2023, 59, 106536.

V. G. Pol, P. Kaur, Methods and Apparatus for sensing volatile organic compounds and gases released from electrochemical cells, US Patent App. 18/107,115.

P. Kaur, S. Bagchi, V. G. Pol and A. P. Bhondekar, J. Phys. Chem. C, 2023, 127, 8373–8382.

P. Kaur, S. Bagchi, D. Gribble, V. G. Pol and A. P. Bhondekar, ACS Sensors, 2022, 7, 674–682.

P. Kaur, I. K. Stier, S. Bagchi, V. G. Pol, A. P. Bhondekar, Batteries, 2023, 9, 1–14.
All-Fiber-Based High Current Density of Triboelectric Nanogenerators Fabrication and for Human Motion Monitoring
Authors: Duo Hao , Wang Haitao , Shota Shima , Takamura Eiichiro , Sakamoto Hiroaki
Published: December 2024

The rapid development in point-of-care (PoC) fields require the continuous and real-time monitoring for the human motion, self-powered and wearable sensors based on triboelectric nanogenerator (STENG) have been an alternative pathway for human health monitoring in our daily life. Ny66, as a synthetic polymer, and biopolymer of chitosan, derived from chitin, represent distinct molecular entities. Despite both containing amino groups, their significantly molecular structural differences enable leveraging their complementary advantages to facilitate internal electron flow towards the friction surface. Meanwhile, electrospinning could promote the transformation of polyvinylidene fluoride (PVDF) fromα, δ, γ and ε phase to β phase, allowing much more excellent triboelectric expression, meanwhile, MCWNT can also act as nano-capacitors for electron storage, consequently, the air break down phenomenon could be alleviated and thereby resulted in the improvement of electric performance. Because of outstanding conductivity and antivirus ability, Ag nanowires (AgNWs) were employed as electrodes. Finally, when we attached the prepared STENG onto the fingertips, wrist and neck to track physiological signals of human state in walking, running, and staying still, respectively. The results show that the as-prepared wearable STENG could distinguish the aforementioned states accurately, therefore, that could be potentially utilized as a promising and non-invasive candidate in PoC and biomedical areas and when attached onto the parts scattered throughout the body.

Figure 1
(Sensor Division Outstanding Achievement Award) IoT Enabled Turnkey Solution for Detection of Multiple Vapor Phase Analytes in Real-World Conditions
Authors: Khosla Ajit
Published: December 2024

We are at the cusp of a massive technological expansion, enabled by the possibility of manipulating and interrogating matter at atomic/molecular level, and conveying the outcome of their molecular information to macroscale observers paving the way for ubiquitous sensing. For example, the full potential of the emerging areas such as Internet of Things (IoT), smart cities, smart homes, autonomous vehicles, additive manufacturing, precision agriculture, fertilizers, wearables, clean energy, long-term environmental monitoring, security etc. cannot be achieved without the mass deployment of inexpensive, miniature turnkey sensor systems capable of generating high fidelity big data for analysis by advanced analytics in real time. Microelectronics plays a critical role in development of such Turnkey solution. By employing micro nano fabrication techniques and development of new semiconductor materials such lithium tantalate, lithium niobate, and micro hotplate fabrication technologies, it is possible to develop sensor arrays with unprecedented capabilities. Such a sensor arrays are then integrated with FPGA, micrococontrollers, power sources and IoT in order to develop turnkey solution for Detection of Multiple Vapor Phase Analytes in Real-World Conditions. The Big Data generated is then analyzed by Artificial Intelligence/Machine learning techniques. Such turnkey solutions have the potential to change the world.

This talk focuses on development of micro-hot-plate-based Turnkey solution and a teaser of:1. lithium tantalate-based sensor arrays; 2. A Turnkey Palm Size Gas Pre-Concentrator System; and 3. IoT Enabled Turnkey System for Destruction, Removal and Monitoring of Micro-Nano Plastics and PFAS from Tap Water with Integrated Sensor Array
(Digital Presentation) Electrochemical Detection of Levofloxacin Using Zn2+-Doped Cobalt Ferrite Nanoparticles from Fennel Extract-Assisted Synthesis
Authors: Prado Hernandez Victor Manuel , Morales Jimmy
Published: December 2024

To solve the problem of detecting drugs derived from fluoroquinolone such as levofloxacin (LV) that is present in aquatic environments, one of the most attractive techniques due to its low cost and ease are electrochemical techniques. LV can be detected using electrochemical techniques such as Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV), where it is relevant to select the working electrode; electrodes such as vitreous carbon are a great alternative due to their high purity. and chemical stability. Furthermore, modifying its surface improves the electrical properties of the material the electrode is made of. An alternative to modify them is the use of metal oxide nanoparticles, whose properties range between being catalytic or their possible use as material for electrochemical sensors. In this work, an investigation of the electrochemical detection of fluoroquinolone derivatives of pharmaceutical interest is proposed using a glassy carbon electrode modified with Zn2+-doped cobalt ferrite nanoparticles from fennel extract-assisted synthesis.

References

Shehzad Khan, Basit Ali, Muhammad Salman, Raz Muhammad, Majid Khan, Fayaz Hussain, Kaixin Song, Dawei Wang. Spinel M5Zn0.5Fe2O4 (M = Ni, Co, and Cu) ferrites for energy storage applications: Dielectric, magnetic and electrochemical properties. Ceramics International, 2022, 48 29291-29297
(Invited) Design, Optimization, and Construction of High-Performance Potassium-Ion Battery Electrodes
Authors: Tuan Hsing-Yu
Published: December 2024

The scarcity of lithium (0.0017 wt% in Earth's crust) casts doubt on the sustainability of lithium-ion batteries (LIBs) for emerging applications such as electric vehicles and large-scale energy storage. In contrast, potassium-ion batteries (PIBs) emerge as a critical alternative due to their low cost, abundant resource availability (2.09 wt% in Earth's crust), and favorable electrochemical characteristics. As next-generation technology demands more versatile, high-density energy storage solutions, PIBs could be game-changers. Despite their promise, PIBs are hampered by issues related to anode materials, especially their dramatic volume changes (~400%) during ion insertion/extraction, causing material disintegration and shortened battery life. This presentation will show strategies for mitigating this volume expansion by employing nanostructured anodes made from high-capacity materials like Bi, Sb, P, and Se. As a highlight, I will discuss our progress in activating these elements to serve as a high-performance PIB anode, achieving record-setting specific energy density. We propose several optimized designs, including heterostructures, high-entropy alloys, solid solutions, and structural reconstructions, and deeply explore the impact of each material on the battery. Not only changes in material structure, but also changes in element selection, crystal structure, and even the formation of heterogeneous interfaces will be the focus of our exploration. At the same time, we are also adding new ideas and developing novel materials, and we hope to break through the limitations of current potassium ion batteries. This innovation opens new avenues for the development of adaptable, high-density energy storage systems for a variety of electronic devices.
(Invited) Design Strategy of High-Performance Hard Carbon Anodes for Sodium-Ion Storage
Authors: Yun Young Soo
Published: December 2024

The advancement of hard carbon anodes with high sodium plateau capacities (SPCs) is currently hindered by a paucity of clear materials design principles. Although the pore volume ratio of hard carbon defines the thermodynamic constraints on the theoretical sodium plateau capacities (T-SPCs), exclusive reliance on pore architecture falls short in predicting viable SPCs. In response, our research explores a pivotal kinetic parameter of hard carbons that influences the coefficient of capacity utilization (CCU) of SPCs. We employ a suite of polymeric hard carbons (PHCs) with varied microstructures to achieve our research objectives. Our systematic investigation reveals a pronounced correlation between the intensity ratio of the 2D to G band (I
2D
/I
G
) in the Raman spectrum and the internal kinetic barrier impeding sodium-ion migration. Leveraging these insights, and by considering both thermodynamic and kinetic facets, we introduce a novel structural gauge – the SPC factor – which serves to quantify the CCU for SPCs. This SPC factor identifies an optimal hard carbon anode configuration that combines a high closed pore volume ratio with a minimized I
2D
/I
G
ratio. By implementing straightforward microstructural modifications to the PHCs guided by our proposed criteria, we have realized significant achievements. Notably, we have attained an SPC of approximately 400 mA h g-1, underscoring the practicality and impact of our strategy in engineering superior hard carbon anodes for sodium-ion batteries. This investigation constitutes a meaningful leap forward, providing a strategic direction for materials design aimed at augmented SPCs and fostering the progression of future sodium-ion battery technologies.
Improved State of Charge Estimation with Pressure Change Characteristics Measurement of LiFePO4 Battery for Electric Vehicle Applications
Authors: Choi Jae Young , Park Jinhyeong , Choi Jinyeong , Kim Tae-hoon
Published: December 2024

The state of charge (SOC) of the battery is an important factor indicating the driving range in electric vehicles. Lithium iron phosphate(LFP) batteries are being increasingly used in vehicles due to their low cost and safety. However, the flat open-circuit voltage (OCV) characteristics of LFP batteries make it difficult to estimate the SOC. Particularly in the SOC range of 30 to 80%, the OCV deviation is 50 mV. Considering the measurement noise in vehicles, this level of voltage variation makes accurate measurement impossible. To solve the SOC estimation issue, automakers are advising users of vehicles equipped with LFP batteries to periodically charge up to 100% using slow chargers for error correction. Consequently, users are experiencing inconvenience. In this paper, we have developed a new estimation algorithm by incorporating the pressure characteristic changes of LFP batteries into the widely used Coulomb Counting Method and the OCV-based Kalman filter SOC estimation method. Using actual vehicle driving patterns, it has been verified that the proposed algorithm controls within ±3% in the SOC range of 30 to 80%.
Specific Analysis of Nonlinear Voltage Behavior with Respect to Activated Carbon in Lithium Ion Capacitors
Authors: Sunhye Yang , Kim Ick-Jun , Jeong Seung Yol , Ryu Jihyeon , Nam Ki-Hun , Kim Sang-gil
Published: December 2024

In order to investigate the influence of nonlinear voltage behavior of cathode-activated carbon on the power characteristics of lithium ion capacitors (LICs), activated carbons with different pore sizes are manufactured. The structures of the activated carbons are analyzed using a field emission SEM and Brunauer-Emmett-Teller (BET) analysis, and the electrochemical characteristics are evaluated from the resistance components and the variations of the discharge inflection points according to the applied current during a discharge of 2.0 to 3.8 V. The nonlinear voltage behavior near 3 V is generated by an ion-exchange of anion (PF6
-) and cation (Li+) in the pores of activated carbon, while the electric double layer (EDL) capacitance in the voltage region exhibits the lowest value compared to the anion-capacitance and cation-capacitance obtained in each linear voltage region. On the other hand, the nonlinear voltage behavior shifts below 3 V and the power characteristic below 3 V rapidly decreases since the average pore size of activated carbon is small and the applied current increases.

Figure 1
Development of Highly Integrated Electric Double Layer Capacitor and Hybrid Capacitor Based on 3D Additive Manufacturing Technology
Authors: Baek JeongHun , Kim Bumjin , Kang Sanghui , Lee Seungho , Yoo Jungjoon
Published: December 2024

Recent development of various small electronic devices has created a need for various types of energy storage devices. Conventional energy storage devices, such as batteries and supercapacitors, are typically manufactured by stacking or rolling film-type anodes, separators, and cathodes, and then injecting liquid electrolytes into the assembly. However, sandwich-structured devices are reaching their limits in terms of ion movement. Moreover, producing customized devices using conventional energy storage technologies is a challenge.

Various technological approaches have been proposed to overcome these limitations. One promising research trend is to develop energy storage devices that achieve high energy density and fast charging by altering their structure, rather than by improving the materials. Interdigital structured electrodes can minimize the distance that ions and electrons need to move, resulting in significant improvements in the device's energy and power density. This approach offers the advantage of producing energy storage devices that cannot be manufactured using web-winding electrode methods, as well as enabling the production of customized devices.

In this work, we developed high-viscosity activated carbon electrode and battery electrode slurries suitable for 3D additive manufacturing technology. The electrodes were printed in an interdigital shape using extrusion-based 3D printing technology to fabricate micro-energy storage devices, such as electric double-layer capacitors, hybrid capacitors, and batteries. The electrochemical properties of the fabricated energy storage devices were evaluated, confirming their high energy density and power density.
Coarsening-Driven Hierarchical Porous Carbon Polyhedrons from Polymer@Metal-Organic Frameworks for Advanced Stretchable Ionogel Supercapacitors
Authors: Kang Min seok , Yoo Won Cheol
Published: December 2024

For ultrahigh-energy-density supercapacitors (SCs), hierarchically interconnected micro-/meso-/macroporous carbons (HICs) are desirable for both effective ion polarization and transport, especially when electrochemically stable but dynamically sluggish ionic liquids are employed as the electrolytes. In this presentation, we develop an effective strategy for preparing HICs with well- developed all-pore regimes for ultrahigh-energy-density SCs using electrochemically stable ionic liquid (IL) electrolytes. The HICs are synthesized via coarsening of the Cu nanoparticles (NPs) within carbon polyhedrons de- rived from the polymer-infiltrated metal-organic framework (MOF). During thermolysis process, the coarsening process of Cu NPs occurs, in which the locations vacated by the Cu NPs are left as large meso -/macropores. HIC polyhedron presents an ultrahigh specific surface area (SSA, 3064 m2 g−1) and the HIC-based SCs exhibit an outstanding capacitance of 268.4 F g−1 with an ultrahigh energy density of 149 Wh kg−1, which are comparable to the best values reported to date, indicating that expedited ion-transport via hierarchically interconnected large meso-/macropores affords maximum utilization of the micropores of the carbon electrodes. Furthermore, stretchable all-solid-state SCs operating at 120% strain with a very high areal capacitance of 33 mF cm−2 and an energy density of 0.041 mWh cm−2 are also demonstrated. These results provide a ubiquitous strategy for developing MOF-based hierarchically interconnected carbonaceous materials with ultrahigh SSA for high-performance SCs compatible with stretchable and wearable electronic devices.
Surface-Functionalized Carbon Linker-Mediated Assembly for Preparing Pseudocapacitive Binder-Free Textile Electrodes
Authors: Ahn Jeongyeon , Ahn Jeongyeon
Published: December 2024

High-performance textile electrodes for pseudocapacitors demands efficient integration of electrochemically active materials and conductive fillers onto current collectors. This is particularly challenging when applying nano-sized, high-energy pseudocapacitive materials due to their poor electrical conductivity. Our study presents a novel method for fabricating such electrodes by directly assembling high-energy nanoparticles (MnOx NPs) onto three-dimensional textile current collectors using surface-functionalized carbon nano-oligomer (CNOs), thereby eliminating inactive or insulating organic components . The assembly process, based on direct interfacial multidentate interactions between MnOx NPs and CNOs, ensures a uniform nano-level distribution across the entire surface of metal textile current collectors. The resulting positive electrodes, referred to as (MnOx NP/CNO)-based textile, demonstrate an exceptional areal capacitance of approximately 1,725 mF cm−2 at 5.0 mA cm−2, which can be further enhanced to around 3,244 mF cm−2 at 10 mA cm−2 through multi-stacking. Moreover, when paired with negative electrodes ((Fe3O4 NP/CNO)-based textile) prepared using the same method, asymmetric full-cell devices exhibit remarkable areal energy/power densities surpassing those of conventional slurry-cast supercapacitors.
Exploration of Low-Temperature Formation Pathways for Garnet-Type Lithium-Ion Conductors
Authors: Onoue Kana , Nasu Akira , Kobayashi Hiroaki , Matsui Masaki
Published: December 2024

[Purpose]

High-temperature sintering is necessary to obtain good contact between the cathode active material and the solid electrolyte in the development of all solid-state batteries. However, high temperature sintering causes the formation of a high resistivity layer, thus reduction of the sintering temperature is desirable. In this study, we investigated a low-temperature synthesis method in garnet-type lithium-ion conductors to synthesize fine particles without crystal growth that exhibit high sinterability at low temperatures. We explored a new reaction pathway to obtain garnet-type lithium-ion conductors at low temperatures by promoting spontaneous reactions between transition metal oxides at low temperatures through the refinement and amorphization of the raw materials.

[Experimental]

Li6.5La3Zr1.5Nb0.5O12(LLZNO) was synthesized by solid phase method using LiOH.H2O, ZrO2.La(OH)3, and amorphous Nb2O5 as precursors. The precursors were synthesized as follows: 1) nano-ZrO2 was synthesized by hydrolysis and coprecipitated with La(OH)3 to form a composite; 2) amorphous Nb2O5 was synthesized by DMF reduction.1

These starting materials were wet ball-milled, then pelletized and sintered at a predetermined temperature for 12 hours under an Ar atmosphere. The products were identified by powder X-ray diffraction. Changes in the local structure and electronic state of the transition metals at different sintering temperatures were analyzed by XAFS measurements.

[Results & Discussions]

Formation of an amorphous intermediate with high reaction activity was observed at 300 ºC by using Amorphous Nb2O5 to enhance the reaction activity of the starting material. The XAFS results show this amorphous intermediate has a disordered structure with a similar coordination environment around Nb to the La3NbO7 crystal phase. The ZrO2 synthesized by hydrolysis is a low-crystalline nanoparticle, and the coordination environment of Zr changes at 100 ºC lower than that of the commercial raw material. The formation of the target cubic LLZNO was confirmed at 400 ºC. The LLZNO crystalline phase formed from this amorphous intermediate is fine and could reduce grain boundary resistance in the preparation of sintered bodies. Finally, a single phase of LLZNO was obtained at 700 ºC, about 300 °C lower than the conventional solid phase method2. In summary, the results show that the destabilization of starting materials are effective for enhancing the reaction of transition metal oxides at low temperatures. These results suggest that controlling the phase stability of starting materials is an important parameter for the design of low-temperature synthesis of cubic LLZNO.

[References]

1: H. Iguichi et al., ACS Appl. Nano Mater., 5, 7658-7663, 2022

2: N. C. Rosero-Navorro et. al, Solid state Ionics, 285, 2016, (6-12)
Towards a Degradation-Free Solid-State Lithium-Sulfur Battery Using Sulfide Glassy Solid-State Electrolytes
Authors: Wheaton Jacob , Leland Stuart , Martin Steve
Published: December 2024

Solid-state batteries present several possible advantages over current lithium-ion batteries, including their enabling of higher capacity lithium anodes, and their removal of flammable organic liquid electrolytes. Sulfide glasses are of particular interest due to their high conductivity, low processing temperatures, and their ability to be formed without grain boundaries. Glasses in the Li2S – SiS2 – LixMOy phase space are being studied for use in lithium-sulfur batteries. While these glasses may appear to be stable against lithium metal during symmetric cell cycling and cyclic voltammetry, they appear to exhibit degradation during full cell cycling. In this study, this degradation is explored through full cell cycling, scanning electron microscopy, and x-ray photoelectron spectroscopy. Multiple glass compositions were explored for their degradation behavior to find a composition that is stable for use in lithium-sulfur batteries, particularly with LiPO3 and LixSiOy as salt dopants to the Li2S – SiS2 parent glass system. The full cells were made using composite cathodes consisting of planetary ball milled glassy solid electrolytes mixed with carbon and lithium sulfide to generate triple-junctions for optimum capacity.
Prediction of Li Ion Conductivity Using a Denoising Autoencoder and an Attention for Experimental Data
Authors: Yokoyama Yumika , Tanihata Naoto , Takeda Hayami , Nakayama Masanobu
Published: December 2024

While all-solid-state batteries composed of inorganic materials are attractive in terms of safety, rate performance is still insufficient. One of the causes is rather poor ionic conductivity of the solid electrolytes, and new high ionic conductive materials are required. Li containing NASICON-type materials are one of candidates due to its high Li ion conductivity. Many efforts have been devoted to improve their Li ion conductivities by changing composition and/or sintering conditions. Meantime, many experimental data, such as optical spectroscopy, diffraction, and so forth, are accompanied in the process of measurements for ionic conductivities. Making a link between ionic conductivity and all the analytical outputs may lead to good guideline for designing materials, though interpretation of analytical output is often difficult.

In this study, we focused on Li1.45Ca0.15Zr1.85Si015P2.85O12 ( LCZSP ) [2] doped with Ca and Si in LiZr2(PO4)3, which belongs to NASICON-type solid electrolyte that exhibits high lithium-ion conductivity and stability against metallic lithium[1]. We reported that the conductivities of this material change depending on the sintering conditions, where we performed 54 synthesis, XRD and Li ion conductivity measurements.[3] Revisiting these experimental data, we tried to make link between XRD and conductivities through machine learning.

Fig. 1 is the schematic representation of the present machine learning model based on deep neural network techniques. An XRD pattern contains noise derived from device, human factors, and so forth. To reduce the influence of noise in the XRD measurement data, a denoising autoencoder was utilized in the model. In addition, XRD patterns are reduced to a two-dimensional representation by the denoising autoencoder and make a link from encoded variables to the ionic conductivities( The blue and yellow areas in Fig. 1 ). The use of the denoising autoencoder enables the construction of a more general model for experimental data. Furthermore, we aimed to enhance the prediction accuracy and interpretability by introducing an attention mechanism that learns the points of interest in the spectrum ( The yellow-green area in Fig. 1 ).

Here, we successfully fit the ionic conductivity through autoencoder derived variables, and confirm an improvement of fitting results by implementation of the attention mechanism. The details will be presented in our poster session.

References

[1] Y. Li, et al.
Proc. Natl. Acad. Sci. U. S. A., 113,13313–13317 (2016)

[2] F. Hiroko, et al., RSC Advanced, 12, 30696-30703 (2022)

[3] H. Takeda, et al., Mater.
Adv., 3, 8141-8148 (2022)

Figure 1
Comparison of Hydrogen Entry in Pure Iron Subjected to Stress in Solution
Authors: Sakuma Keiji , Saito Hiroyuki
Published: December 2024

We found that the difference of measured desorption curves in several treatment case of iron. This study was aimed at comparison of hydrogen entry in pure iron subjected to stress in solution. Pure iron plates were used in this experiment and were subjected to elastic/ plastic deformation using a four-point bending. The plates were exposed to 1M-NaOH aqueous solution, and cathodic hydrogen charging for the plates was performed for 24 hours at a potential of -1.220 V vs. SSE. The amount of hydrogen entering the solution was then measured up to 400 ℃ by thermal desorption analysis (TDA). The results of study showed that the amount of hydrogen ingress during elastic deformation was almost the same as that during no-load. However that during plastic deformation of pure iron increased.

Figure 1
Titanium Compound Coating on SUS Separator for PEFC By Screen Printing
Authors: Yabe Moeka , Watanabe Hikari , Shitanda Isao , Itagaki Masayuki , Kogure Tomonari , Tanino Hitoshi
Published: December 2024

Currently, the metal separators of polymer electrolyte fuel cells (PEFCs) are mainly made of Ti alloys with press working. According to the report by Strategic Analysis Inc1), Ti separator accounts for a large ratio of the PEFC stack cost. To reduce this cost, it is effective to use inexpensive stainless steel and to apply the coating by screen printing, which is relatively easy to form patterns and less expensive than evaporation or sputtering. However, stainless steel has lower corrosion resistance than that of titanium, and its conductivity decreases in aqueous solution due to the formation of passive film. The purposes of this study are to develop a coating with excellent corrosion resistance and conductivity, as well as adhesion and durability, and to apply the coating on stainless steel by screen-printing. Titanium nitride and titanium carbide were employed as tillers among titanium compounds that have high corrosion resistance and sufficiently low electrical resistivity comparable to that of titanium. As a result of the research, a coating thickness of several hundred micro-m became possible, and it was decided that the gas flow path fabrication would also be done by screen printing.

In this experiment, we used titanium nitride powder with different particle sizes, Olycox KC-1300 as binder, and 2-(2-butoxyethoxy) ethyl acetate as solvent to prepare printing pastes. 4 g of binder and 10 mL of solvent were weighed and stirred at 80°C for 12 hours using a magnetic stirrer. 4 g of the stirred solution was mixed with 4 g of titanium nitride powder to form a paste. The paste was screen-printed on SUS304 using a plate simulating a gas flow channel, and then dried at 250°C for 6 hours. The resistance of the coatings prepared by the above method was evaluated after pressure treatment. In addition, anodic polarization was measured in a three-electrode system. The contact resistance was targeted to be less than 10 mΩcm2 , the target value for the contact resistance of PEFC separators, as specified by the U.S. DOE.2)

References

1) Mass Production Cost Estimation of Direct H2 PEM Fuel Cell Systems for Transportation Applications: 2017 Update, Brian D. James, Jennie M. Huya-Kouadio, Cassidy Houchins, Daniel A. DeSantis, Strategic Analysis Inc., December 2017.

2) Fuel Cell Technologies Multi-Year Research, Development, and Demonstration Plan, U.S. DOE, 2017
The Effect of the Nano-Sized Plastic on Activated Carbon (AC) Electrode and Ion-Exchange Membrane (IEM) in Membrane Capacitive Deionization (MCDI)
Authors: Hwang Boogyu , Park Sanghun
Published: December 2024

The emerging water treatment technology, membrane capacitive deionization (MCDI), utilizes ion exchange membranes (IEM) and porous electrodes to adsorb ions from low-concentration brines or inorganic wastewater. Numerous studies about salt adsorption capacity (SAC) of MCDI have been conducted as it indicates the performance of desalination system. Former studies have shown that how various factors influence on the ion removal efficiency of MCDI, such as operating conditions (e.g., ion voltage, flow rate) and water quality parameters (e.g., natural organic matters, heavy metals). In recent years, micro-sized plastic particles (<5mm) and nano-sized plastic particles (1-1000nm) have become a serious problem that threatens water resources as plastic product consumption has increased. Especially, nano-sized plastics, due to their extremely small size, not only contaminates water resources but also can impair the water treatment system. Nano-sized plastics are expected to pass through the pores (100-200nm) of ion exchange membranes (IEMs) in MCDI, given their smaller size compared to the pores of IMEs. Consequently, the porous electrodes could be clogged, leading to a reduction in specific surface area. The reduction may occur due to the potential impact of nano-sized plastics on the pores (>50nm) of the electrodes, resulting in a decrease of the SAC of MCDI. This study investigated the effect of nano-sized plastic on the porous electrodes and the performance of MCDI. The potential impact of newly exposed nano-sized plastics on water electrochemical water treatment system will be introduced.
Impact of Natural Organic Matter (NOM) on Nitrate Adsorption in the Membrane Capacitive Deionization (MCDI) Process
Authors: Park Hui Sang , Park Sanghun
Published: December 2024

Fertilizers containing nitrates significantly boost agricultural productivity, resulting in their extensive application in many regions. However, the majority of nitrate found in water originates from these fertilizers, leading to a gradual increase in nitrate concentration. Nitrogen-catalyzed eutrophication of surface waters leads to algal blooms, resulting in deterioration of water resources. Overexposure to nitrate has adverse effects on plants, the health of animals and humans. The contamination of water resources due to nitrates is becoming a serious issue. Thus, addressing the necessity of nitrate removal becomes important in safeguarding both environmental sustainability and public health. A variety of water treatment technologies for nitrate removal have been developed. Recently, membrane Capacitive Deionization (MCDI) is widely utilized for nitrate removal due to its high ion adsorption capability and selectivity. Meanwhile, there has been insufficient investigation regarding the effect of natural organic matters (NOM) found in natural water resources, which is expected to significantly degrade the salt adsorption capacity of MCDI. Moreover, the mechanism of NO3− adsorption in the presence of NOM in the electrosorption process has not yet been shown clearly. Therefore, more research efforts are needed to investigate the effect of NOM and its significance on MCDI to effectively remove nitrate during operation. In this study, we investigated the influence of NOM on the adsorption of nitrate in the MCDI process. Feed water with and without NOM was analyzed to examine changes in the performance of nitrate adsorption. This study will introduce a decrease in nitrate adsorption rates in water containing NOM due to the formation of complexes facilitated by organic matter.
Selective Electrochemical Nitrate Reduction to Ammonia on Co-Based Catalysts
Authors: Quinones-Gomez Laura , Dinh Cao Thang
Published: December 2024

About 150 million metric tons of ammonia (NH3) were produced in 2023 mainly for agricultural purposes as a fertilizer [1]. This compound is industrially produced by the conventional Haber-Bosch process under high temperatures (350 – 550 °C) and high pressure (150 – 350 atm), thus, its production accounts for 1.8 tons of CO2 emissions per ton and 2% of the energy consumed in the world [2]. These factors have led to an interest in developing green alternative methods that allow the production of large amounts of NH3. Therefore, it has been demonstrated that the electrocatalytic synthesis of NH3 is a viable route that can be developed via the reduction of nitrate (NO3
-) to simultaneously mitigate its pollution in water sources, which has become a major human health concern when it is consumed [3]. Since the electrochemical reduction of NO3
- involves a complex eight – electron process, it is vital to design a highly selective, active, and stable catalyst. In this work, the performance of Co-based catalysts in alkaline conditions was evaluated and our studies demonstrated that a three-dimensional (3D) Co substrate can achieve a faradaic efficiency (F.E.) of up to 86% at +0.023 V vs RHE (Reversible Hydrogen Electrode) with a partial current density of 23 mA cm-2. However, in the presence of an excess of NH3, Co corrosion is promoted while creating a Co-NH3 complex. In order to avoid this, the thermo-oxidation of Co foam at 400, 600, and 800 °C was performed, proving that a larger oxide layer improves the stability as well as increases the active surface area of the electrode. Furthermore, the samples could reach greater current densities when subjected to a pre-reduction treatment. The sample oxidized at 600 °C presented superior performance, achieving a F.E. of 66% at +0.023V vs RHE, a partial current density of 170 mA cm-2, and approximately 8 h of stability. This work has provided an opportunity to explore the influence of the oxide layer on NH3 synthesis, as well as the necessity of advancing novel strategies to enhance the selectivity and stability of the proposed catalyst.

[1] Production of ammonia worldwide from 2010 to 2023. Statista (2024). Retrieved from: https://www.statista.com/statistics/1266378/global-ammonia-production/#:~:text=Ammonia%20production%20has%20remained%20fairly,approximately%2064.6%20million%20metric%20tons.

[2] Wang, J., Cai, C., Wang, Y., Yang, X., Wu, D., Zhu, Y., Li, M., Gu, M., & Shao, M. (2021). Electrocatalytic Reduction of Nitrate to Ammonia on Low-Cost Ultrathin CoOx Nanosheets. ACS Catalysis, 11(24), 15135–15140. https://doi.org/10.1021/acscatal.1c03918

[3] Xu, H., Ma, Y., Chen, J., Zhang, W., & Yang, J. (2022). Electrocatalytic reduction of nitrate: a step towards a sustainable nitrogen cycle. Chemical Society Reviews, Issue 7. https://pubs.rsc.org/en/content/articlelanding/2022/cs/d1cs00857a
Fabrication of Nanopillar Arrays with Wettability Gradients by Nanoimprinting Using Anodic Porous Alumina Molds
Authors: Uchimura Misaki , Kitahara Runa , Yanagishita Takashi
Published: December 2024

When water droplets form on a surface with a continuously changing wettability, they spontaneously move from a higher to a lower water droplet contact angle. Such wettability gradient surfaces are expected to have a variety of applications, including analytical chips that do not require pumps. We previously reported that the formation of a wettability gradient surface is possible by continuously varying the pore size of anodic porous alumina obtained by the anodization of an Al substrate [1,2]. In this report, we describe the formation of nanopillar arrays with a wettability gradient by nanoimprinting using anodic porous alumina with continuously varying pore sizes. The results of the evaluation of the transport distance of water droplets formed on the surface of the resulting nanopillar arrays are also shown. This method makes it possible to impart wettability gradient properties to various substrate surfaces.

Ideally ordered anodic porous alumina with an interpore distance of 1 μm was obtained by the anodization of an Al substrate. The resulting anodic porous alumina was immersed in phosphoric acid solution at a constant speed to produce a hole array structure with continuously varying pore sizes. Polymer nanopillar arrays with continuously varying diameters were obtained on glass substrates by nanoimprinting using the resulting anodic porous alumina as a mold. The surfaces of the resulting polymer pillar arrays were hydrophobically treated, and the contact angles of the water droplets were measured. Water droplets were formed on the surface of the polymer pillar array, and the spontaneous transport distance of water droplets was measured.

SEM observations showed that polymer pillar arrays with continuously changing diameters were formed via nanoimprinting. From the contact angle measurements, it was confirmed that the contact angle changed continuously as the diameter of the nanopillars changed. When water droplets formed on the surface of the nanopillar arrays, spontaneous movement of the droplets was observed. This method is effective as a surface treatment for the spontaneous transport of water droplets on various substrate surfaces.

References

[1] T. Yanagishita and Y. Boushi, Langmuir, 39, 862 (2023).

[2] Y. Boushi and T. Yanagishita, Langmuir, 40, 5455 (2024).
Enhanced SnO2 FETs via Selective Area Fluorination doping process
Authors: Kim SeonChang , Chung Roy ByungKyu
Published: December 2024

Currently, there is active research on oxide semiconductors suitable for the next-generation integration technology, Monolithic 3D Integration (M3D). Among back-end-of-line (BEOL) compatible material candidates, SnO2, with its high mobility and wide bandgap (3.6 eV), is extensively utilized in the fields of solar cells and displays, semiconductors benefiting from excellent power efficiency, high price competitiveness, and transparency. Furthermore, the fluorine-doped tin oxide (FTO) is a highly transparent and conductive semiconductor, serving as a Transparent Conducting Oxide (TCO) widely utilized in various electronic and optoelectronic devices.

In this study, we fabricated SnO2 Thin Film Transistors (TFTs) utilizing SnO2 deposited by Thermal-Atomic Layer Deposition (T-ALD) as the channel layer. Additionally, the surface of the SnO2 in the Source/Drain regions was n+ doped through fluorination to enhance ohmic characteristics between the electrode and the channel layer. In this process, we have successfully fabricated SnO2 TFTs demonstrating excellent electrical characteristics, with a very high on/off current ratio exceeding 1013 and a low Subthreshold Swing (S.S) of 0.18 V/dec, achieved by effectively controlling the conductivity of SnO2. These results emphasize the potential of ALD SnO2 channels for high-performance transistors that are compatible with back-end-of-line processes in Si technology.

Figure 1
(General Student Poster Award Winner, 3rd Place) Probing the Trends of Cation Interactions in Cation Exchange Membranes Using Raman Spectroscopy
Authors: Beswick Rebecca , Smith Wilson A
Published: December 2024

Cation exchange membranes (CEMs) are an ion exchange polymer which selectively shuttles cations through their structure. CEMs are used for a wide range of electrically driven processes, including electrolysis, fuel cells, and electrodialysis. Historically, fluorinated polymers have been used as CEMs, with the most prevalent being Chemours’ Nafion polymer. These materials and their synthesis can produce harmful, long-lived environmental toxins that may provide challenges to scaling to meet material demand. Therefore, significant research is being directed towards finding non-fluorinated CEMs with similar functionality. One promising candidate has been sulfonated poly-ether-ether-ketone (SPEEK), which has similar ion exchange capabilities as Nafion, while being low cost and non-fluorinated.

In electrochemical reactors, the effect of different cations in electrolyte solutions has shown high importance for overall conductivity and can affect reaction selectivity, activity, and durability. The cations which move through the CEM (mobile ions) can interact with the fixed sulfonate functional groups on the polymer backbone. While there is significant research on mobile ion effects on the performance of Nafion1, far less work has been done in this area with SPEEK2. Additionally, there are no direct comparisons between Nafion and any non-fluorinated polymer on how the polymer backbone affects these mobile ion interactions.

One method to study CEM-ion interactions is with Raman Spectroscopy, which uses a monochromatic light to initiate and observe Raman scattering from matter. While Raman spectra have been obtained for Nafion, we have not found Raman spectra of SPEEK in the presence of different electrolyte compositions. Here, we use Raman spectroscopy paired with water uptake and conductivity measurements to compare the differences of how a variety of mobile cations (H+, NH4+, Li+, Na+, K+, Rs+, Cs+, Mg2+, Ca2+, Sr2+) interact with the fixed sulfonate functional groups found in Nafion and SPEEK. We report that the two polymers show differences in the strength of the interactions between the mobile ions and fixed groups, which leads to changes in physical properties, including water uptake and conductivity. With these findings, more informed decisions of the applications of fluorinated vs non-fluorinated polymers for various electrochemical purposes can be made.

Key References:

[1] Peng, J. Tian, M. Cantillo, N.M., and Zawodzinski, T., Electrochimica Acta.
282, 544–554 (2018).

[2] Pérez-Pérez, M. and Suleiman, D., Journ of Mem Science. 493, 414–427 (2015).

[3] Maier, M. Abbas, D. Komma, M. Mu’min, M.S. and Thiele, S., Böhm, T., Journ of Mem Science. 669, 121244 (2023).
Electrophoretic Deposition of High Entropy Metal Phosphate Nanoparticles for Efficient Oxygen Evolution Reaction in Alkaline Media
Authors: Lee Hyeonseok , Ha Don-Hyung
Published: December 2024

Through electrolysis utilizing renewable energy sources such as solar and wind power, green hydrogen can be produced without unwanted byproducts. For efficient electrolysis, a high-performance oxygen evolution reaction (OER) catalyst is required. Transition metal-based catalysts in alkaline electrolysis have been extensively studied, offering not only their lower cost compared to noble metal catalysts including Pt, Ir, and Ru but also promising high stability and performance. Particularly, high entropy materials (HEMs) composed of five or more elements in a homogeneous mixture exhibit unique catalytic activity not solely explained by hydrogen adsorption energy, owing to the broadening and mixing of d-band centers of constituent elements. Furthermore, the overall stability of high-entropy materials (HEM) in catalytic reactions is attributed to solid-solution strengthening and the sluggish atomic diffusion effects resulting from their high entropy.

In this work, we fabricated high entropy nanoparticles, where multiple elements are uniformly mixed, via a reverse precipitation method. The precursor introduced into the precipitant promptly reacted, disregarding the distinct precipitation rates of individual elements, successfully forming a random and homogeneous single phase, including transition metals (M = Cr, Mn, Co, Fe, Ni, Cu, and Zn). To further enhance catalytic performance, additional different sized atoms such as Mo and W were also incorporated during the synthesis process leading to lattice distortion of the surface atomic structure.

To fabricate alkaline OER electrodes using synthesized catalysts, the Electrophoretic Deposition (EPD) method was utilized attaching nanoparticles onto substrates. The resulting catalyst electrodes exhibited optimized performance with two rounds of EPD process, each lasting 10 minutes at an applied voltage of 1000V on Ni foam. The electrode fabricated through EPD outperformed those made using drop casting with Nafion binder in experimental comparisons, demonstrating superior performance.