bluuebunny/crossref_metadata_2025 huggingface dataset:
Equivalent Circuit Modelling for Electrode-Supported Solid Oxide Cell Based on Analysis of Gas and Temperature Dependence
Authors: Budiman Riyan Achmad , Konishi Rikuto , Yamaguchi Mina , Kawada Tatsuya , Yashiro Keiji
Published: December 2024

Electrochemical impedance spectroscopy (EIS) measurement is used to determine the performance of solid oxide cells (SOCs). In the commercial-type of SOC such as an electrode-supported cell (ESC), all reaction resistance is sometimes combined into one spectrum, making it difficult to deconvolute the reaction resistance. The distributed-relaxation times (DRT) is often used to deconvolute the impedance spectra into a several reaction resistances. However, the DRT analysis cannot give any physical meaning to each reaction resistance of SOC’s components. Thus, it is necessary to build an equivalent circuit model to describe the physical meaning of each resistance.

In this study, the ESC (Nexceris, USA) with a composition of Ni-YSZ (yttria stabilized zirconia) as a fuel electrode, 8YSZ as an electrolyte, Ce0.9Gd0.1O1.95 as an interlayer, and La0.6Sr0.4CoO3-

δ
(LSC) as an electrode was measured by EIS as a function of oxygen partial pressure, hydrogen partial pressure, water vapor partial pressure, temperature, and carbon dioxide partial pressure under open circuit voltage (OCV). At first, the impedance spectra were analyzed by the DRT method using software “FTIKREG” [1] based on Tikhonov regularization. After that, the complex nonlinear least square (CNLS) equivalent circuit was developed and fitted to the obtained impedance spectra.

The gas conversion and diffusion at a very low-frequency region were analyzed by the Warburg impedance, meanwhile, the electrode resistance was perfectly fitted by the Gerischer impedance. The analysis result on the air electrode resistance of LSC showed the transport properties such as oxygen exchange coefficient and oxide ion diffusivity of the LSC air electrode close to the reported data on the bulk electrode [2]. Meanwhile, the analysis result on the Ni/YSZ fuel electrode resistance showed a good agreement on the reaction resistance and chemical capacitance from the reported data [3].

Despite the developed model is “well-fitted” with the obtained impedance spectra, the analysis only done at OCV. In the real operating condition such as fuel cell or electrolysis mode the applied bias is used. Thus, the impedance spectra will slightly be different to those obtained under OCV. Therefore, the developed model will be also fitted to the impedance spectra under applied bias. The analysis result will be used to discuss the application of the developed equivalent circuit model.

Acknowledgement

This study was supported by the New Energy and Industrial Technology Development Organization (NEDO), grant number JPNP16002.

Reference

[1] J. Weese, Computer Physics Communications, 69 (1992) 99-111.

[2] D. K. Hohnke et al., Solid State Ionics,5 (1981) 531-534.

[3] M. Takeda, K. Yashiro, R. A. Budiman, S. Hashimoto, T. Kawada, J. Electrochem. Soc., 170 (2023) 034505.
Electrochemical Cation Implantation-Induced Surface Defect and Phase Engineering of MoS2 for High-Efficiency pH-Universal Hydrogen Evolution Reaction
Authors: Song Byunggon , Lee Ji Hoon , Jeong Hyung Mo
Published: December 2024

Hydrogen, which has a high gravimetric energy density (approximately 120 MJ kg⁻¹) and serves as an energy carrier, can be produced through electrochemical water splitting systems. However, developing materials that are usable for water splitting over a wide pH range presents significant challenges. Moreover, platinum, which is known to be the most effective for hydrogen production, is constrained by its high cost and rarity. Therefore, there is a need to develop non-precious metal alternatives. Transition metal dichalcogenides (TMDs), particularly MoS2, have emerged as promising candidates to address these issues due to their impressive hydrogen evolution activity in acidic conditions. Nonetheless, further improvements are needed to enhance its performance in alkaline and neutral environments. In this study, we have successfully improved the electrocatalytic properties of MoS2 using an electrochemical cation implantation process. This approach led to the creation of Mo and S vacancies and the phase transition of MoS2 from the electrochemically inert semiconducting (2H) phase to the more active metallic (1T) phase. The optimized MoS2 exhibited exceptional catalytic activity (eta10, 144 mV) across a wide pH range, outperforming the pristine MoS2. This research suggests that enhancing electrocatalytic performance can be achieved by simultaneously manipulating both phase and defect structures.
Understanding the Excited Properties and the Luminescence Mechanisms of ns2 Type Ion Doped Phosphors: A First-Principles Study
Authors: Lou Bibo
Published: December 2024

Luminescent materials doped with ns2-type ions, such as Bi3+, Sb3+ ions, exhibit several excited states that can provide optical transitions, including the optical transitions within the electronic configuration of ns2 ions, the valence band to ns2 ions charge transfer (CT) transitions, the metal-to-metal charge transfer (MMCT) transition between the ns2 ions and the conduction band, and the intervalence charge transition (IVCT) between the dopant pair. The luminescence properties of these materials are significantly influenced by the environment, making the ns2 ions excellent activators for phosphors. Our talk will present the first-principles studies that revealed the geometric and electronic structures of the ground and excited states of ns2 ions, constructed the configuration coordinate diagrams, and analyzed the dynamic processes of excitation, relaxation, and emission. We will also briefly present some work on ns2 ions doped phosphors studied by the combination of first-principles and experimental methods, demonstrating the importance of theoretical calculations for the design and performance improvement of novel luminescent materials.

Figure 1
Development of QD-OLED and Thin Film Encapsulation Technology Using Inkjet Printing
Authors: Kwon Byoung-Hwa , Shin Jin-Wook , Kang Chan-Mo , Cho Hyunsu , Joo Chul Woong , Choi Sukyung , Cho Nam-Sung , Byun Chun-Won
Published: December 2024

In the display industry, inkjet printing has the advantages of high material use efficiency, digital control, and non-contact printing. Additionally, it is advantageous for large-area processing and flexible/stretchable device applications. Due to these attractive advantages, technology development to apply the printing process to the display mass production process has continued for a long time. The quantum dot organic light-emitting diode (QD-OLED) panel recently developed by Samsung Display showed that inkjet printing technology can stably implement not only the encapsulation process but also light-emitting pixels.

In this study, we first describe the encapsulation technology for OLED devices developed using inkjet printing used in industrial mass production processes. Specifically, TFE (Thin Film Encapsulation) with a 1.5-dyad structure in which organic and inorganic layers exist alternately was implemented and the structure was analyzed. We then introduce the results of applying this TFE to flexible OLED devices and panels.

Next, we describe QD-OLED manufacturing technology using inkjet printing. Specifically, QD-OLED integration technology is explained focusing on the top-emitting OLED process, QD pixel definition layer process, and QD inkjet printing process. We introduce the electrical and optical analysis results of the QD-OLED produced in this way.
Development of a Streaming Potential-Driven Electrolysis System: Reductive Hydroxylation of Aromatic Boronic Acids
Authors: Iwai Suguru , Suzuki Taichi , Villani Elena , Sato Kosuke , Hasegawa George , Ishizuka Norio , Matsukawa Kimihiro , Tomita Ikuyoshi , Inagi Shinsuke
Published: December 2024

Bipolar electrodes (BPEs), driven by an electric field in low-concentrated electrolytes, are paying more and more attention due to their unique features such as wireless nature and gradient potential distribution(Figure 1a)1. Recently, we achieved electrochemical fluorination using a bipolar electrode, reducing the amount of supporting electrolyte that becomes waste after the reaction2,3. However, the driving electrodes generating an electric field may induce side reactions during electrolysis. Using streaming potential is a key strategy to solve this problem (Figure 1b). Streaming potential is a potential difference generated by a laminar flow of low-concentrated electrolytes inside a narrow channel4. Indeed, an anodic dissolution of metallic silver5 and electropolymerization of aromatic monomers6 were achieved in bipolar electrode systems driven by the streaming potential (Figure 1c).

In this work, we aimed to expand this electrolysis system to molecular transformations. The reductive hydroxylation of aromatic boronic acid was selected as a model reaction (Figure 1d) 7. To amplify the streaming potential, we employed various porous fillers packed in narrow flow channels. Polymer resin fillers with continuous porous monolith structures showed high streaming potential. Then, the hydroxylation using streaming potential was carried out by pumping the solution containing 4-(methylthio)phenylboronic acid. As a result, the reaction current was observed between bipolar electrodes, and the desired phenol product was detected by 1H NMR, suggesting that the proposed electrochemical hydroxylation proceeded without a power supply. Through the investigation of the concentration of substrates, electrode surface area, and additives, the yield and conversion yield were increased to 9.0% and 97.3%, respectively. The details of the streaming potential measurements and hydroxylation will be presented in the talk.

References

N. Shida, Y. Zhou, S. Inagi, Acc. Chem. Res., 2019,52, 2598–2608.

K. Miyamoto, H. Nishiyama, I. Tomita, S. Inagi, ChemElectroChem, 2019, 6, 97–100.

H. Sakagami, H. Takenaka, S. Iwai, N. Shida, E. Villani, A. Gotou, T. Isogai, A. Yamauchi, Y. Kishikawa, T. Fuchigami, I. Tomita, S. Inagi, ChemElectroChem, 2022, 9, e202200084.

A. V. Delgado, F. González-Caballero, R. J. Hunter, L. K. Koopal, J. Lyklema, J. Colloid Interface Sci., 2007, 309, 194–224.

I. Dumitrescu, R. K. Anand, S. E. Fosdick, R. M. Crooks, J. Am. Chem. Soc., 2011, 133, 4687–4689.

S. Iwai, T. Suzuki, H. Sakagami, K. Miyamoto, Z. Chen, M. Konishi, E. Villani, N. Shida, I. Tomita, S. Inagi, Commun. Chem., 2022, 5, 66.

K. Hosoi, Y. Kuriyama, S. Inagi, T. Fuchigami, Chem. Commun., 2010, 46, 1284–1286.

Figure 1
Sustainable Electrochemical Olefin Epoxidation via Porphyrin Based Molecular Catalysts
Authors: Kim Sojin , Yadav Dibya , Baek Eunji , Jin Kyoungsuk
Published: December 2024

Electrochemical synthesis of small molecules has been considered as a promising alternatives to replace the current thermochemical synthetic routes. By harnessing electricity under benign conditions instead of toxic reagents and stoichiometric redox agents, this method is able to provide environmentally friendly methods with no greenhouse gas emissions. Epoxidation, a pivotal oxidation reaction with widespread significance in both academia and industry, typically relies on thermochemical pathways, accompanying several disadvantages including harsh operating conditions, the use of hazardous oxidizing agents, and substantial greenhouse gas emissions. In this study, we have established an electrochemical epoxidation scheme employing molecular catalysts. We explored metalloporphyrin catalysts, leveraging their biomimetic properties resembling cytochrome P-450, known for its high catalytic activity in selective monooxygenation reactions. Also, we used water as the oxygen atom source for the epoxidation. We aimed to probe the effect of metals and ligands of porphyrin catalysts for the epoxidation reaction. By investigating the catalysts with various metals and ligands, we observed that the selective epoxide formation occurred exclusively with the Mn-Por complex with phenyl ligands. Additionally, a series of electrokinetic studies were conducted to elucidate the detailed reaction mechanism. We believe our approach presents a sustainable methodologies for the electrochemical production of high-value-added chemicals.
(Invited) Flash Electroorganic Chemistry Guided By Flow Microreactor Research
Authors: Nagaki Aiichiro
Published: December 2024

Many successful applications reported in the literature speak well for the power of the flow-microreactor method in chemical synthesis. The authors propose “express organic synthesis” inspired by the recently developed flash microflow system. To create a more economical and efficient system for sustainable chemistry, we need to speed up not only the reaction rates, but also synthetic steps, manufacturing systems, and even research itself. Express organic synthesis has great potential for eventually reducing energy and carbon losses. In this presentation, we slow our recent results. Especially, we focus on flash electororganic chemistry that are difficult or even impossible to perform in batch processes can be accomplished in flow microreactors.
(Invited) Hydroflux Process as a Low-Temperature Synthesis of Layered Cathodes
Authors: Matsui Masaki
Published: December 2024

Layered LiCoO2 (LCO) is usually synthesized at high temperatures ≥ 800 °C by conventional solid-state processes. It also has another polymorph with a spinel phase, which is synthesized around 400 °C. Hence, the layered LCO and the spinel LCO have been called HT-LCO and LT-LCO, respectively. Conversely, first-principles calculations predicted that the layered LCO is thermodynamically stable even at low temperatures. Furthermore, an in situ XRD study revealed that the spinel LCO formation is the topotactic displacement of the Co2+ or Co3+ ion at the 8a site in the Co3O4 spinel with two Li+ ions. Therefore, layered LCO should be obtained even at low temperatures. Here, we propose an effective synthesis approach called the “hydroflux process” to synthesize a highly crystalline layered LCO at low temperatures of ≤ 300 °C within a short duration of ≤ 1 h. Our synthetic strategy uses a eutectic LiOH-NaOH binary alkaline hydroxide as the lithium source and the flux for crystal growth. Since the eutectic point of the mixed hydroxide is 220 °C, the obvious crystal growth of LCO was observed at 250 °C and above. We also found that the crystal water of the LiOH monohydrate showed obvious crystal growth of the layered LCO even at low temperatures. We also investigated the phase evolution of the starting materials during the hydroflux process at 300 °C. The series of the XRD patterns showed that the starting material of Co(OH)2 transformed to a rocksalt CoO after 10-15 minutes of heating. Subsequently, the layered LCO formation was observed during the following 15 minutes. The crystal growth of the layered LCO was completed within 30 minutes of the heating duration. The observed reaction pathway shows that the water molecules significantly accelerate the crystal growth of the layered LCO in the molten hydroxide. The formation of soluble cobalt species of HCoO2
– ion at high pH conditions enables the crystal growth of the LCO at low temperatures. We also attempted to synthesize LiNiO2 and ortho-LiMnO2 at 300 °C. Controlling the oxidation state of transition metals becomes a key parameter for the development of our synthetic strategy. We believe that the hydroflux process has the potential to revolutionize the synthesis of layered cathode active materials, offering a rapid and scalable solution.
Ultrastable Cathodes Enabled by Controlled Ordered to Disordered Structure
Authors: Liu Tongchao , Amine Khalil
Published: December 2024

Cathodes for next generation batteries are pressed for higher voltage operation (≥4.5V) to achieve high capacity with long cyclability and thermal tolerance. However, no existing cathode simultaneously fulfills all these requirements because high voltages lead to excessive Li extraction which places the materials under structural and electrochemical strains far beyond their thermodynamic stability limits. As a result, Li-deficient frameworks at high voltages are inherently fragile and susceptible to structural degradation, which leads to fast capacity fading, an issue that has yet to be resolved. Here, we show a new cathode option with a controlled structurally coherent architecture ranging from ordered to disordered framework that can fundamentally solve these challenges and break the voltage ceilings long imposed by existing cathodes. The novel cathode merges the advantages of ordered and disordered structures to simultaneously blend high-capacity and high-voltage operation at 4.5V without any capacity fading and even up to 4.7 V with negligible capacity decay, which the current known cathodes cannot achieve, even with cutting-edged modifications. Leveraging multiscale diffraction and imaging techniques, we reveal that the designed disordered structure surface is electrochemically and structurally indestructible even at harsh operating voltages due to densely packed framework and controllable Ni oxidation activities. This effectively alleviates surface parasitic reactions and irreversible phase transitions. In addition, structural coherence from ordering to disordering limits lattice parameter changes and mitigates lattice strain, resulting in enhanced morphological integrity with no particle cracking. Thermal stability was also significantly improved with this unique design. We expect that this innovative structural design will inspire a new wave of efforts to develop high performance cathodes for next generation battery materials.
High Charge-Discharge Performance of Stacking-Sequence Disordered SiC as Anode Material for Lithium-Ion Battery
Authors: Ohyanagi Manshi , Hayashi Yura , Shirai Kenshiro , Imai Takahito , Ohta Minehiko
Published: December 2024

Much attention has been paid on Si, SiO and the composites with graphite as anode materials for lithium-ion battery. The issue of huge volume change in lithiation and delithiation which leads the less reversible capacity retention is serious and most of the efforts to overcome it has been directed to insert any kinds of buffers including the mechanical into the negative electrode material. Another attractive candidate as the anode material is β-SiC. One of major problems to develop the semiconductive β-SiC as the anode material is the loss of conduction pass inside the materials just like Si and SiO. β-SiC possesses zinc blend type of cubic structure with regularly stacked three close packed layers.

We found that stacking-sequence disordered SiC (SD-SiC), not the three dimensionally ordered crystal like cubic β-SiC, with amorphous carbon as conduction pass worked as the anode material with the high discharge capacity of 1490mAh/g-Si (or 1040mAh/g-SiC) at 50mA/g after 14 cycles in the half-cell with Li as the counter electrode. In this work, the synthesis of SD-SiC with amorphous carbon, the discharge rate property and the cycle performance in the half-cell will be described.
Hierarchical Ni-Mn Oxides@Silicene Flower As Anode Materials for Fast-Charging Lithium-Ion Batteries
Authors: Tsai Ting-Jang , Yeh Che-Ning
Published: December 2024

The fast-charging capability and energy density of lithium-ion batteries (LIBs) are critical limiting factors for the widespread adoption of electric vehicles. Silicon-based anodes are considered promising candidates for next-generation LIBs due to their high theoretical capacity, faster reaction kinetics, and enhanced Li+ diffusion. However, the dramatic volume change during lithiation/delithiation and poor intrinsic electric conductivity of silicon-based materials contribute to poor cycle stability, thereby limiting their application as anode material for LIBs. In this work, we investigate the potential of silicene flower (SF) as a fast-charging anode material. SF comprises interconnected silicene nanoplates arranged in various spatial orientations, forming a three-dimensional flower-like structure. SF demonstrates superior ability to accommodate the volume changes of silicon and shorten lithium-ion diffusion length. Additionally, we introduce Ni-Mn oxides as a protective layer to accommodate the volume expansion of silicon. Notably, Ni-Mn oxides exhibit high theoretical capacity, excellent reversibility, and good rate performance. Furthermore, we incorporate reduced graphene oxide (rGO) to facilitate a rapid electron transport pathway and accommodate the space between expanded particles. The Ni-Mn oxides protective layer between silicon and rGO serves to prevent the chemical side reaction that forms Li2SiF6, as carbon material can catalyze this reaction. This composite anode material offers both economical and environmentally friendly benefits, synthesized via a non-toxic process. Our work provides a promising approach to the realization of fast-charging anodes with higher rate capabilities, further advancing the prospects of safer and higher energy density next-generation LIBs.
Structural and Chemical Evolution of Highly Fluorinated Li-Rich Disordered Rocksalt Oxyfluorides as a Function of Temperature
Authors: Sunariwal Neelam , Cabana Jordi
Published: December 2024

Li-rich disordered rock-salt oxyfluorides (DRS) represent a novel category of cathode materials characterized by remarkable electrochemical performance (references [1,2]). The substitution of oxygen (O) with fluorine (F) in DRS materials yields a notable enhancement in reversible discharge capacity, rendering them promising candidates for future high-energy Li-ion batteries with elevated capacity. Despite extensive exploration of their structural and electrochemical attributes, very little attention has been paid to their thermal stability. DRS oxyfluorides can be synthesized through solid-state and mechanochemical ball milling methods (references [3-5]). While solid-state synthesis is constrained by limited fluorine solubility compared to mechanochemical ball milling, the latter method generates metastable materials. Some studies have employed thermal treatment to enhance the structural stability and capacity retention of DRS, yet a comprehensive understanding of their inherent stability upon thermal treatment remains elusive (references [5,6,7]).

To bridge this knowledge gap, our research delves into the thermal stabilities of Li2MO2F compositions featuring various M elements (M = Mn, Ni, and Co) and delineates the structural transformations at different temperature regimes. We employ a combination of analytical techniques including X-ray diffraction, NMR, and X-ray absorption spectroscopy to elucidate alterations in the local structure of oxyfluorides and their decomposition into other phases. This presentation will elucidate the impact of thermal treatments on chemical and structural characteristics by leveraging distinctive spectral attributes. Furthermore, we will elucidate how a comprehensive understanding of these thermally treated F-rich phases correlates with enhanced electrochemical performance and capacity retention, positioning them as viable candidates for battery cathode materials.[8]

References:

D. A. Kitchaev et al., Energy Environ. Sci., 11, 2159–2171 (2018).

D. Chen, J. Ahn, and G. Chen, ACS Energy Lett., 6, 1358–1376 (2021).

X. Xu et al., J. Electrochem. Soc., 168, 080521 (2021).

Y. S. Moghadam, A. E. Kharbachi, G. Melinte, T. Diemant, and M. Fichtner, J. Electrochem. Soc., 169, 120514 (2022).

I. Blumenhofer et al., ACS Mater. Au (2022) https://doi.org/10.1021/acsmaterialsau.2c00064.

J. Huang et al., Small Structures, 4, 2200343 (2023).

H. Ji et al., Chem. Mater., 31, 2431–2442 (2019).

N. Sunariwal et al., Adv. Funct. Mater. 2024, 34, 2312010

Figure 1
Design of Functional Electrolytes for Automotive Lithium-Ion Batteries
Authors: Deguchi Masaki , Todorov Yanko Marinov , Abe Koji
Published: December 2024

Lithium-ion secondary batteries are increasingly used in large power sources such as EVs, and ensuring battery safety has become an important issue as the batteries become higher voltage and higher capacity. In 1999, we proposed a "functional electrolyte" in which a small amount of an additive with a new function is added to the electrolyte. Since then, many additives have been commercialized. Among them, a mixture of ethylene carbonate (EC), which has a high dielectric constant, and ethyl methyl carbonate (EMC) or dimethyl carbonate (DMC), which has a low viscosity, with additives is used as the electrolyte for current automotive lithium-ion batteries (LIB).

However, the flash point of these electrolytes is as low as 25°C, so we have been investigating high-safety electrolytes, focusing on solvents with flash points of 120°C or higher. But it has been found that if only high flash point EC, propylene carbonate (PC), or γ-butyrolactone (GBL) solvents are used, they cannot wet the hydrophobic separator whose material is polyethylene (PE) and/or polypropylene (PP). As the first theme of our presentation, we focused on a low viscosity linear carboxylic acid esters and designed an electrolyte with a flash point above 120°C that provides wettability to the separator even in an electrolyte with a high dielectric constant solvent. Based on this, using EC and GBL as a high flash point solvent and LiFSI as a thermally stable Li salt, we will report our investigation of additives to prevent corrosion of Al current collectors due to LiFSI in this high-safety electrolyte.

Another safety issues, when a battery is overcharged, the cathode and anode electrodes become thermally unstable and the battery's Joule heat increases, leading to thermal runaway. To suppress this, we have been vigorously developed additives for overcharge prevention. On the other hand, little research has been conducted on overdischarge prevention. The battery module discharge termination voltage is fixed in the device / power supply, but sequentially connected single cells in the assembled battery may be overdischarged, and there is a concern that the battery performance is hindered by the dissolution of the Cu current collector. As the second theme of our presentation, we focused on additives with carbodiimide groups (N=C=N) to prevent dissolution of Cu current collectors during overdischarge and will report the unique phenomenon.
Elucidation of the Mechanism behind High-Valence Element Doping in Ni-Rich Cathode Materials
Authors: Park Nam-Yung , Sun Yang-Kook
Published: December 2024

Layered cathode materials, LiMO2 (M=Ni, Co,Mn, or Al), with a high nickel content are promising cathode materials owing to their near-theoretical specific capacity. However, the inherent chemical and structural instabilities of Ni-rich cathodes lead to several problems, including rapid capacity fading, thermal instability, gas evolution, and safety concerns.1

Introducing additional elements into Ni-rich cathodes is an essential strategy for addressing the instability of the cathode material. Conventionally, this doping strategy considers only the incorporation of additional elements into the bulk structure of the cathode in terms of fortifying the crystal structure.2 However, high-valence elements are likely to be insoluble in the crystal structure, resulting in accumulation along the interparticle boundaries.3 Herein, a new mechanism for doping high-valence elements into Ni-rich cathodes and their effects on the morphology and crystal structure are investigated by calcining LiNiO2 (LNO) and X-doped LNO cathodes (X=Al, Nb, Ta, and Mo) at various temperatures. Operando X-ray diffraction analysis reveals that the temperature at which the content of Li-X-O compounds declines is higher for the dopants with high oxidation states, reinforcing segregation at the grain boundary. Thus, the highly aligned microstructure and high crystallinity of the LNO cathode are maintained over a wide calcination temperature range after doping with high-valence elements, enhancing the electrochemical performance.

References:

[1] N.-Y. Park, G.-T. Park, S.-B. Kim, W. Jung, B.-C. Park, Y.-K. Sun, ACS Energy Lett.
2022,7, 2362.

[2] X. Ou, T. Liu, W. Zhong, X. Fan, X. Guo, X. Huang, L. Cao, J. Hu, B. Zhang, Y. S. Chu, G. Hu, Z. Lin, M. Dahbi, J. Alami, K. Amine, C. Yang, J. Lu, Nat. Commun.
2022,13, 2319.

[3] G.-T. Park, D. R. Yoon, U.-H. Kim, B. Namkoong, J. Lee, M. M. Wang, A. C. Lee, X. W. Gu, W. C. Chueh, C. S. Yoon, Y.-K. Sun, Energy Environ.Sci.
2021,14, 6616.
Water-Based Pickering Emulsion Scheme for One-Step Washing and Coating High-Ni Layered Cathode for Lithium-Ion Batteries
Authors: Park Seongeun , Lim Jong-Heon , Park Kyu-Young
Published: December 2024

High-nickel layered oxides have gained significant attention in a lithium-ion rechargeable battery (LIB) system due to their high energy density[1]. However, their severe anisotropic volume changes upon de/lithiation result in mechanical degradation issues, ultimately deteriorating cycle life[2]. Moreover, the unstable surface of the nickel element and the high-temperature synthesis conditions contribute to the residual lithium on the surface, giving rise to electrode engineering hurdles such as slurry gelation and gas evolution[3]. To prevent these major problems, In this research, we propose an innovative water-based Pickering emulsion CNT coating scheme to increase the mechanical strength and residual lithium issues, simultaneously[4]. This approach offers a straightforward physical coating process, facilitating rapid water-washing during CNT coating and minimizing surface damage caused by water in vulnerable high-nickel materials. Using ethyl cellulose in the CNT coating process facilitates stable CNT dispersion and emulsion formation. Additionally, ethyl cellulose forms a hydrophobic layer on the active material surface, addressing moisture sensitivity issues post-water-washing[5]. The synergistic effects of CNT coating and efficient removal of residual lithium enhance the electrochemical cycle life, achieving over a 20% increase in capacity retention compared bare washing after 200 cycle at 1C. This economically and environmentally advantageous water-based coating method is applicable not only to high-nickel cathodes but also to other battery materials requiring CNT coating for enhancing electronic conductivity and suppressing volume change.

Reference

[1] Nature Energy. 2020, 5, 26–34

[2] Chem. Mater .
2018
, 30, 3, 1155–1163

[3] ACS Energy Lett.

2021
, 6, 3, 941–948

[4] Adv. Energy Mater.2020, 10, 2001216

[5] Chem. Mater. 2023, 35, 5150
−5159
Lithium-Doped Nickel Iron Oxyhydroxide Nanosheets Coupled Polyaniline As Bi-Functional Electrocatalysts for Hydrogen/Oxygen Evolution Reactions at All pH Levels
Authors: Lingappan Niranjanmurthi , Lee Wonoh
Published: December 2024

Hydrogen represents a carbon-free and sustainable energy carrier. Electrochemical water splitting via hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is a green approach for the hydrogen production.

Nevertheless, unfavorable thermodynamics and sluggish kinetics limit the water splitting efficiency. While the benchmark catalysts such as Pt@C and RuO2/C catalysts display remarkable catalytic activity, the inferior durability remains a major concern. Further, scarcity and high demand result in sharp rise in cost, hindering their large-scale commercialization. Herein we report the synthesis of lithium-doped nickel iron oxyhydroxide nanosheets gown on polyaniline functionalized carbon fiber as (Li@NiFeOOH@PANi-CF) as bi-functional electrocatalyst for HER and OER. In this design, the interfacial PANi layers substantially improve the surface functionality of the CF substrate and thereby facilitates strong coupling interaction with the Li@NiFeOOH catalyst, which influences the charge transport kinetics across the catalyst/substrate interface and also maintains the structural integrity of the overall catalyst throughout the cyclic and long-term durability tests. Furthermore, the Li@NiFeOOH provide abundant active sites for the dissociation of water, while the PANi-CF facilitates the adsorption of H+ ions from the intermediates and promotes its convention to hydrogen molecules, which accelerates the HER effectively. Due to these intriguing features, the Li@NiFeOOH@PANi-CF manifested remarkable HER efficiency with low overpotential (34, 42, and 53 mV mV at 10 mA cm-
2) in acidic, alkaline, and neutral electrolytes. Besides, the Li@NiFeOOH@PANi-CF demonstrated better OER durability even in acidic electrolyte. As a key functionality, PANi layers protected the carbon surface from corrosive reactions and suppressed the active catalyst dissolution, resulting in high tolerance for both HER and OER at all pH conditions.
Oxidizing Gas Reverses Thermal Ripening of Ni Particles into Single Atom for Solar-Driven Biocatalytic Hydrocarbon Oxygenation
Authors: Kim Chang Hyun , Oh DongHwan , Seo Hwakyoung , Hollmann Frank , Han Jeong Woo , Jung WooChul , Park Chan Beum
Published: December 2024

Single atoms (SAs), or individual heteroatoms have garnered much interest due to their potential on the revolution of the chemical and energy industrial fields with exceptional metal utilization and unforeseen catalytic advantages from non-ensemble sites. Typically, SAs are synthesized through bottom-up methodologies that involve the ligation between support materials and metal salts. Conversely, there are only a few reports on top-down methods, and even these are primarily focused on precious group elements supported by metal oxide. Coarsening of nanoparticles happens at high temperatures due to the thermal Brownian motion, and ripening as well. Vice versa to this general situation, top-down approaches in building a SA catalyst by virtue of the re-dispersion of nanoparticles have received great attention due to their unique feasibility and unexpected ensemble effects.

In this study, we showcased a novel method where transition metals are dispersed into individual heteroatom sites on an urchin-like titanium nitride support, following the oxidizing annealing process. We elucidated that the initial metal nanoparticles transform into SA during this process, catalyzing the phase transition of nitride lattice to oxide by harvesting the oxygen itself. By adjusting the oxidizing gas species, we controlled the optimal oxidation state of the support with Ni SA, resulting in sufficient and consistent hydrogen peroxide (H2O2) production via photocatalytic 2-electron oxygen reduction reaction (2e-ORR). We further integrated this photocatalytic 2e-ORR with a peroxygenase biocatalysis dependent on H2O2 to facilitate the photoenzymatic oxyfunctionalization of inert hydrocarbons, leading to the synthesis of enantiopure alcohols and epoxides. Our novel top-down approach to SA catalysts finely tunes the electronic structure of transition metals on the support, enabling the synergistic combination of heterogeneous photocatalysis and enzymatic catalysis.
Photoelectrochemical Ammonia Oxidation on Porous Organic Polymer Modified BiVO4
Authors: Koh Taesik , Shit Subhash Chandra , Kim Wooyul
Published: December 2024

Advancing sustainable and clean energy technology is imperative in addressing the energy and environmental crisis. As an energy carrier, hydrogen has been getting attention due to its abundance, high energy density, and zero carbon emissions. Given the challenges associated with hydrogen storage and transportation, the oxidation of ammonia presents significant promise for renewable energy. Photoelectrochemical ammonia oxidation reactions (AOR) have garnered substantial interest, which demand active and stable photo-electrocatalyst. In this regard, we fabricated Ov-BiVO4/Ph-POP photoelectrodes by controlling the oxygen vacancies of pristine BiVO4 and depositing Ph-POP, a hydroxy-rich porous organic polymer, using a simple spray coating method. We conducted the AOR in both aqueous electrolytes and non-aqueous electrolytes like acetonitrile (CH3CN), resulting in improved photocurrents and enhanced stability compared to aqueous conditions for the cases of Ov-BiVO4 and Ov-BiVO4/Ph-POP. Importantly, Ov-BiVO4/Ph-POP demonstrated superior activity across all electrolyte solutions. This indicates that Ph-POP's capacity to enhance light absorption and provide adsorption sites for ammonia facilitates the oxidation reaction. These findings provide compelling evidence for the role of Ph-POP and pave the way for exploring the potential use of porous organic polymers in AOR.
Solution Plasma Treatment for the Enhancement of Activity and Durability in Mn-Doped Ca3Co4O9
Authors: Hirai Shigeto , He Hao , Jeevan Kumar Padarti , Ohno Tomoya , Matsuda Takeshi
Published: December 2024

The oxygen evolution reaction (OER) is a key reaction for emerging energy conversion technologies such as electrochemical water splitting and rechargeable metal–air batteries. In this talk, we will introduce the solution plasma treatment as a powerful tool for the dual enhancement of activity and durability in a Mn-doped Ca3Co4O9. Specifically, we find that Mn-doping in combination with solution plasma treatment boosts the OER activity of Ca3Co4O9 by a factor of 11, along with the remarkable enhancement of the OER durability. Moreover, the solution plasma treatment of Mn-doped Ca3Co4O9 has an effect of improving the atomic order of the OER active Mn3+-rich surface, which contributes to the better understanding of oxygen evolution catalysis.
Improving the Stability of Ni-Fe-Based Electrodes Via Bias Modulation in Alkaline Water Electrolyzer
Authors: Im Han Seo , Lim Sung Yul
Published: December 2024

Green hydrogen, produced through water electrolysis, is a vital clean energy source in pursuing carbon neutrality. nickel-iron (Ni-Fe) based materials are especially recognized for their high oxygen evolution reaction (OER) activity in alkaline environments. Despite their promise, the low thermodynamic stability of Ni-Fe materials, particularly the dissolution of iron ions during extended electrolysis, poses a significant challenge. In this study, we developed Ni-Fe-based bifunctional electrodes with enhanced hydrogen evolution reaction (HER) and OER activity, along with improved stability. The electrodes were fabricated using zinc phosphating, a surface coating technique known for its simplicity and efficiency. Rather than focusing solely on the basic electrode materials, we prioritized operational strategies, such as bias switching, to enhance both activity and stability. We further improved the electrode stability by intermittently applying a reverse voltage instead of maintaining a constant one. This study suggests that bias modulation may offer a promising approach to overcoming the stability limitations of Ni-Fe-based electrodes in alkaline water electrolysis (AWE).
(Invited) Nanosensors for Health Monitoring of Environmental Exposures
Authors: Lin Yuehe , Du Dan (Annie)
Published: December 2024

Biomonitoring of environmental exposures is a critical area of public health that involves tracking the presence and impact of toxic substances in human populations. As industrial and agricultural activities increase, so does the risk of exposure to harmful pollutants, including smoke from cigarettes and wildfires, as well as pesticide residues. Traditional monitoring methods often require bulky equipment and complex procedures. In this talk, we will discuss innovative strategies for using functional nanoparticles and single-atom catalysis to enhance signal detection in biosensing. We will also explore the application of 3D printing technologies for the fabrication of compact sensor arrays. These advancements have led to the development of miniature biosensors that can be integrated with smartphone technology, enabling real-time, point-of-care biomonitoring. This approach not only increases the accessibility of environmental health diagnostics but also enhances the ability to respond rapidly to public health threats. The applications of these nanosensors in detecting exposures to cigarette smoke, wildfire smoke, and pesticides will be highlighted, demonstrating their potential to revolutionize the field of environmental health monitoring.
Point-of-Care Neurofilament Light Detection for Neurological Disease Monitoring
Authors: Churcher Nathan , Prasad Shalini , Rizvi Fatima
Published: December 2024

Neurofilament light chain (NfL) is a cytoplasmic protein predominantly found in neurons. Its primary role is to provide structural support to myelinated axons during their growth and maintenance. When axons are damaged due to injury or neurodegenerative processes, NfL levels increase in various bodily fluids, including the extracellular matrix, cerebrospinal fluid (CSF), and blood. The clinical significance of NfL lies in its association with neurological conditions. High levels of NfL have been observed in several contexts:

Medical Emergencies: In acute medical emergencies such as stroke and head injuries, elevated NfL levels are detected. This rapid response makes NfL a potential biomarker for assessing acute neuronal damage.

Neurodegenerative Diseases: Chronic neurodegenerative conditions, including multiple sclerosis (MS) and Alzheimer's disease, are characterized by progressive neuronal loss. NfL levels are significantly elevated in these diseases, reflecting ongoing axonal damage.

Monitoring Neurodegeneration: Utilizing NfL as a monitoring tool has gained attention. Its presence in easily accessible bodily fluids (such as blood) makes it valuable for creating point-of-care mechanisms. By tracking NfL levels over time, clinicians can assess disease progression, treatment response, and overall neuronal health.

Current NfL monitoring techniques such as Fourth-Generation Immunoassays (SIMOA or Quanterix). These highly sensitive assays allow quantification of NfL even at low levels. They are particularly useful for measuring NfL in plasma and serum. However, they require specialized equipment and trained personnel, limiting their widespread adoption. Microfluidic Cartridge-Based Automated Immunoassay Platforms such as ELLA have also been employed. While these platforms offer automated NfL measurement more conveniently, they also require expensive equipment and proper sample transportation.

In this proposal, we introduce a novel Point-of-Care (PoC) mechanism designed for the rapid detection of Neurofilament Light Chain (NfL) in blood plasma. Our approach aims to eliminate the need for sample transportation, reduce procedural delays, and improve turnaround time. We have developed an Electrochemical Impedance Spectroscopy (EIS) platform specifically tailored for quantifying NfL levels within the physiological range in plasma. By leveraging the chemical interactions between the NfL antibody and antigen, we detect changes in impedance at the electrode-electrolyte interface as a factor of the chemical interaction. To validate our platform, we conducted spike and recovery experiments. These experiments illustrate the platform's ability to detect NfL in plasma samples reliably. In summary, our proposed PoC mechanism represents a significant advancement in NfL monitoring for neurodegenerative diseases. By combining accessibility, precision, and rapidity, we aim to enhance patient care and disease management.
Highly Efficient Colloidal Quantum Dot-Based Shortwave Infrared Photodetectors
Authors: Jung Yujin , Baek Se-Woong
Published: December 2024

The ability to detect infrared (IR) light is essential for a variety of emerging applications such as recognition systems, bio-imaging, spectroscopy, and object inspection. Particularly crucial is the capture of photons beyond the edge of silicon absorption, which is vital for advancing long-range communications and quantum technologies. Colloidal quantum dots (CQDs), which are semiconductor nanocrystals, offer a versatile alternative with their ability to tune the bandgap from visible to shortwave-infrared (SWIR) wavelengths through quantum confinement. Nevertheless, challenges persist in CQD-based IR optoelectronics, including the use of hazardous elements like Pb, Cd, and Hg, and their generally lower performance when compared to epitaxial semiconductors. This presentation highlights the development of IR devices using safe, non-toxic CQD materials, including groups III-V and I-VI, among others. By applying various short-ligand passivation techniques, we are able to produce stable CQD ink that forms high-quality conductive films. Our findings indicate that the degree of ligand passivation significantly influences a surface-mediated photomultiplication effect, substantially enhancing device responsivity. Additionally, we have achieved efficient avalanche breakdown within the CQD multiplication layer, resulting in rapid response times under a nanosecond and a significant gain of approximately 10,000. This sets a new benchmark for gain x bandwidth product among all previous solution-processed IR photodetectors operating at 1550 nm.
Square Wave Voltammetry-Based Sensor for Precise Leucovorin Level Monitoring in Artificial Urine: A Leap Towards Personalized Cancer Treatment
Authors: Shum Pui Hang , Denanny Lynn
Published: December 2024

Recent trends in healthcare underscore a paradigm shift towards personalized precision medicine, emphasizing the necessity to customize treatments for individual patients based on their unique responses to diseases and therapeutic interventions. This approach represents a departure from the traditional "one size fits all" model toward a more stratified care methodology.1, 2

Our study explores the potential of square wave voltammetry (SWV) in actualizing a practical approach for monitoring therapeutic drug levels in the biological matrices Using leucovorin calcium (LV), a common cancer treatment drug, as our target model, we illustrate SWV's capability for monitoring circulating medication concentrations within artificial urine.

We showcase an affordable, user-friendly, and portable sensor that has proven effective in the detection of LV at clinically relevant concentrations (0.5 – 30 µM) directly in artificial urine samples, negating the need for complex sample processing. Preliminary explorations also show promising applications in analyzing other bodily fluids, such as saliva and serum.

The sensor design discussed herein serves as an initial demonstration of how such electrochemical sensors can be adapted for point-of-care usage. Its simplicity and the elimination of elaborate sample preparation procedures could significantly enhance utility in clinical environments, potentially revolutionizing the role of electrochemical sensors in healthcare and increasing their accessibility to healthcare professionals for enhanced patient care.

Our research contributes to the field of precision medicine by providing a proof-of-concept that demonstrates the effective employment of electrochemical sensors in therapeutic drug monitoring.

K. Brown and L. Dennany, Sensors and Actuators Reports, 2021, 3, 100065.

I. R. König, O. Fuchs, G. Hansen, E. von Mutius and M. V. Kopp, European Respiratory Journal, 2017, 50, 1700391.

Figure 1