bluuebunny/crossref_metadata_2025 huggingface dataset:
Bifunctional Cofe-Spinel@Cu for Peroxymonosulfate Activation and Electrochemical Nitrate Reduction Towards High Purity Ammonia Production
Authors: Kim Yerin , Lee Jimin , Cho Kangwoo
Published: December 2024

Ammonia is a valuable chemical feedstock and energy carrier with lower corbon footprint during conversion to H2. Haber-Bosch process is the predominant method for industrial NH3 production, but it is associated with high energy consumption and substantial CO2 emission. Recently, electrochemical nitrate reduction reaction (NO3RR), powered by renewable energy in ambient condition, has emerged as a promising method for sustainable NH3 production from nitrate containing wastewater. However, the purity of generated NH3 by NO3RR is also a critical issue that has been overlooked in state-of-the-art reports. In the case of nuclear and steelmaking wastewater, abundant nitrate ions and organic pollutants coexist. Therefore, additional step is required to separate the NH3 generated by the NO3RR from the wastewater matrix. Herein, we designed a coupled NO3RR-PMS activation electrocatalytic system to achieve a high-purity NH3 production. CoFe-spinel on Cu foam (CoFe/CF) was employed both as a cathode for NO3RR and catalyst for chemical PMS activation. The CoFe-spinel was prepared through a straightforward hydrothermal deposition on Cu foam, followed by cathodization in nitrate solution. It achieved 90% faradaic efficiency for NO3
--to-NH3 conversion and NH3 production rate of 1.10 mmol h-1 cm-2 at -0.4 V RHE, together with long-term durability for about 150 h (in 0.1 M nitrate solution at pH 14). Additionally, it demonstrated approximately 90% efficiency in removing organic pollutants via PMS activation (with 10 mg L-1 SMX solution at pH 14). Thus, the coupled NO3RR-PMS activation system, utilizing the CoFe/CF catalyst, produced NH3 with a high purity. The cathodization step generated CoFe2O4 nanostructure with well-developed oxygen vacancies, to provide plentiful active hydrogen for the observed cutting-edge figures of merit for NO3
--to-NH3 conversion. Operando analysis based on X-ray absorption spectroscopy is ongoing to reveal the genuine active site for PMS activation or NO3RR. The proposed system would offer an efficient technology for high-purity NH3 production from nitrate wastewater.
Computational Modeling of Anion Exchange Membrane Water Electrolysis
Authors: Kim Youngkeun , Kim Yeonghyun , Lee Donggyun , Kim Junghwan
Published: December 2024

Reducing greenhouse gas emissions in all sectors through energy transition using green hydrogen as renewable fuel is required to conform to Paris Climate Agreement. Anion exchange membrane (AEM) water electrolysis based on renewable energy sources is one of the promising strategies due to its cost effectiveness and absence of corrosion problem. However, proving the durability, reliability, and efficiency of AEM electrolysis is challenging. In this study, AEM electrolysis modeling based on computational fluid dynamics (CFD) was proposed for analyzing multi-dimensional and multi-phase phenomena inside the electrolysis cell. To guarantee the high fidelity of proposed model, parameter estimation and validation with lab-scale experimental data were conducted, showing high accuracy. Parameter estimation was performed through optimization-based approach and four system-dependent parameters were selected: anode / cathode roughness factor, membrane conductivity, and interfacial resistance. The result showed that the more hydrogen is observed in the outlet as the voltage increases while overall durability of cell reduces due to increase in temperature difference and pressure drop. The proposed model expected to show the enhanced performance if optimal flow patterns with operating conditions are found.
(Luminescence and Display Materials Division Outstanding Achievement Award) Fiat Lux
[1], or the Lighting Story of the Transition Metal and Rare Earth Ions
Authors: Brik Mikhail G.
Published: December 2024

Nowadays getting artificial light is of paramount importance in all domains of human life. The story of the artificial light sources began with the invention of the incandescent lamps in the second half of the XIX century, followed by the fluorescent lamps and, finally, by discovery and development of the light emitting diodes (LED) in the end of the XX century. Modern LEDs have numerous advantages over their lighting predecessors: considerably longer life time, brightness, lower energy consumption, miniature size, flexibility etc. The lighting industry now is a very important sector of the world economy with huge ever-growing market. The main goal of the LED producers is to make the light sources that are able to produce light as close to the natural Sun light as possible.

The transition metal and rare earth ions with unfilled 3d and 4f electron shells, respectively, are vital components of the phosphor materials that have to be used in lighting devices for getting emission of different colors. Modern white LEDs are the phosphor-converted LEDs, based on the combination of the GaN (or GaInN) blue LED and one or two phosphor materials, that partially absorb blue light and convert it into emission of other colors (usually yellow and red), to make together white light.

In this presentation different theoretical models that are used to describe the electronic and optical properties of those 3d and 4f ions in optical materials will be discussed, with an emphasis on the transition metal ions with the 3d3 electron configuration (Cr3+ and Mn4+, in particular). Complicated interplay of electronic properties of impurity ions and host materials will be considered; the “structure-optical property” relationships will be considered. Some useful suggestions for tuning the optical properties of these ions in solids will be outlined.

[1] Let there be light (Latin)
Toward Semiconductor Laser Cooling Using CsPbBr3 Nanocrystal
Authors: Ding Yang , Zhang Zhuoming , Ghonge Sushrut , Kuno Masaru
Published: December 2024

Photoexciting an emissive material can lead to refrigeration, a phenomenon known as laser cooling. Laser cooling relies on a highly efficient phonon-assisted single-photon up-conversion anti-Stokes photoluminescence (SP-ASPL). In practice, achieving laser cooling requires nearly perfect emission quantum yields (QYs) and SP-ASPL up-conversion efficiency.

CsPbBr3 nanocrystals (NCs) are promising for this purpose due to their near-perfect QYs and efficient SP-ASPL up-conversion. We've developed a consistent method to produce NCs with near-perfect QYs (QY>96%). Our nuclear magnetic resonance studies reveal that the close-packing surface is key to these high QYs. Further investigation of these NCs shows a near-unity SP-ASPL up-conversion efficiency (~100%) in our obtained CsPbBr3 NC, which does not follow the typical Arrhenius behavior. Our developed polaron model helps explain this phenomenon. These findings lay the groundwork for advancing laser cooling using CsPbBr3 NCs.
Siloxane-Encapsulated Perovskite Nanocrystal for Highly Stable Color-Converting Material in Displays
Authors: Jang Junho , Kim Young-Hoon , Shin Yongmin , Kwon Byoung-Hwa , Bae Byeong-Soo
Published: December 2024

Perovskite Nanocrystals (PNCs) have emerged as a high-performance color-converting materials in displays because of low material cost, facile color tunability depending on size or composition, high photoluminescence quantum yield (PLQY), and very narrow emission spectra, which allow them to achieve wide color gamut. Although they exhibit high optical performance, perovskite nanocrystals (PNCs) are vulnerable to decomposition or aggregation in humid or high-temperature environments, stemming from ion migration and the development of metastable states. Stability of PNCs have been increased by various methods such as formation of an inorganic shell, Janus structures, and NC/polymer nanocomposites. However, such strategies still showed limited stability of PNCs under ambient air or in water and entail complex processes to prevent aggregation of NCs in polymer matrixes. Moreover, PNCs that are stable under harsh conditions (acid or base solutions, polar solvents, high temperature with high humidity) have not been reported. Especially methylammonium (CH3NH3
+, MA) based PNCs decay faster in the presence of moisture than do others such as formamidinium or cesium or mixed cation-based PNCs even it can be fabricated by simple process. Therefore, highly stable, and uniformly dispersed PNC composites without complex processes such as ligand-exchange and formation of an inorganic shell are desirable.

Herein, we report a simple but effective materials-design approach to achieve extraordinarily long stability of crosslinked MA lead bromide (MAPbBr3) NCs in various environments (air, water, chemicals, high temperature (85 °C) with high relative humidity (85%RH) (85 °C/85%RH)) by employing sol-gel derived methacrylate-functionalized siloxane hybrid matrix. The methacrylate in the siloxane matrix induces a chemical crosslinking with unsaturated hydrocarbon in acid (oleic acid) and base (oleylamine) ligands in PNCs at a molecular scale, to form a chemically crosslinked perovskite NCs with siloxane hybrid (CPN) that prevents decomposition of MA from the perovskites and achieves homogeneous distribution of NC in the siloxane matrix. Moreover, the low concentration of moisture that diffuses through the siloxane matrix during aging can chemically heal surface defects in the NCs, and thereby reduce nonradiative recombination in CPN. As a result, CPNs showed high PLQY of ≈70% which remained for >600 d in air, water and acid or base solutions, and various polar solvents, and for >100 d under 85 °C/85%RH. We demonstrate wide color gamut and stable color-converting white LEDs and OLEDs by integration with red-emissive Cd-based QDs. Moreover, water- and chemical-persistent CPNs were successfully applied to cell proliferation which has been impossible with water-sensitive materials with toxic elements (e.g., Cd and Pb).
Deep Eutectic Solvents As Novel Solvent-Electrolyte System for Electroreductive Transformations
Authors: Steffensen Astrid Kjær , Lundberg Helena , Riisager Anders
Published: December 2024

Organic electrosynthesis is regarded as a sustainable alternative to traditional organic synthesis as it enables replacement of stochiometric redox agents with electricity – which can be generated from renewable sources – and high product selectivity at ambient conditions [1]. However, the poor conductivity of the organic solvents typically requires the addition of large amounts of supporting electrolyte salts, leading to increased waste generation and lowered atom economy of the process.

Alternative solvents such as room temperature ionic liquids (RTILs) and deep eutectic solvents (DESs) represent a promising alternative electrolyte and solvent in electrosynthesis. They are conducting, non-volatile and able to solubilize several organic compounds as well as easily separated from products by extraction and thus prone for reuse [2-4]. In addition, they have a tunable, large electrochemical window and this has already led to their use as electrolytes in other fields of electrochemistry, including batteries, electrochromic devices, supercapacitors and in electrodeposition processes [5-6].

DESs offer some advantages compared to RTILs, including that their synthesis is comparable inexpensive and simple, requiring no purification. In addition, some of the DES are biodegradable. DESs have already been use in organic synthesis as solvents and catalysts, however only few examples use DESs as electrolyte systems in organic electrosynthesis despite their advantageous properties. DESs can also solubilize untreated biomass and biomass components, and thus they are attractive solvents for several biorefinery processes including pretreatment, fractionation, and catalytic conversion [7]. Selective reductive transformations are key in biomass valorization to yield precursors for fuels and chemicals.

In this work, we show how DESs can play a dual role as solvent and electrolyte for reductive transformations of organic compounds. The physical and electrochemical properties of the DESs and their role in the reaction are investigated. In addition, the feasibility of reusing the DES over several reactions is examined.

[1] Frontana-Uribe, B.A.; Little, R. D.; Ibanez, J. G.; Palma, A. & Vasquez-Medrano, R. Green Chem.
2010, 12, 2099-2119.

[2] Singh, S. K. & Savoy, A. W. J. Mol. Liquids
2020, 297, 1120938

[3] Hansen, B. B.; Spittle, S.; Chen, B.; Poe, D.; Zhang; Y., Klein; J. M.; Horton, A.; Adhikari, L.; Zelovich, T.; Doherty, B. W.; Gurkan, B.; Maginn, E. J.; Ragauskas, A.; Dadmun, M.; Zawodzinski, T. A.; Baker, G. A.; Tuckerman, M. E.; Savinell, R. F. & Sangoro, J. R. Chem. Rev. 2021, 121, 1232–1285.

[4] Kathiresan, M., & Velayutham, D. Chem. Commun.
2015, 51, 17499.

[5] Armand, M.; Endres, F.; MacFarlane, D. R.; Ohno, H. & Scrosati, B. Nat. Mater.
2009, 8, 621–629.

[6] Abbott, A. P. Curr. Opin. Green Sustain. Chem.
2022, 36, 100649.

[7] Wang, Y.; Kim, K. H.; Jeong, K.; Kim, N. K.; Yoo, C. G. Curr. Opin. Green Sustain. Chem.
2021, 27, 100396.
Synthesis of Polybromothiophene By Electrooxidative Polymerization and Its Polymer Reactions
Authors: Matsumura Yoshimasa , Hokimoto Sota
Published: December 2024

π-Conjugated polymers exhibit unique properties such as electronic conductivity, photoluminescence, and visible light absorption due to the delocalization of π-electrons on the main chain. Although these polymers are typically synthesized by polycondensation techniques using transition metal catalysts, this method can not be used for polymerization of monomers containing reactive building blocks for transition metal catalysis. To prepare reactive precursors for catalytic transformation, we focused on electrochemical synthesis of bromo-substituted polythiophene for introduction of various functional groups through cross-coupling reactions and reactions with electrophilic agents via lithiation. the halogenated polythiophene can not be prepared by polycondensation using transition metal catalysts. In this paper, we describe synthesis of polybromothiophene by electrooxidative polymerization, which is inert to Ar-Br bonds, and its polymer reactions by Suzuki-Miyaura coupling reaction using aryl boronic acid and a Pd catalyst (Scheme 1).

Electrooxidative polymerization of 3-bromo-4-dodecylthiophene (1) was carried out using a Pt plates (2 × 2 cm2) electrode in an acetonitrile solution of Bu4NPF6 (100 mM) by constant potential electrooxidation at 2.4 V for 60 seconds at room temperature. After the reaction, a dark blue polybromothiophene (2) film was deposited on the anode. The color of the polymer changed from dark blue to orange after precipitation into methanol. The number-average molecular weight (M
n) and molecular weight distribution (M
w/M
n) of 2 were estimated to be 15,000 and 2.8, respectively, by size exclusion chromatography (SEC). The structure of 2 was confirmed by 1H and 13C NMR spectra and EDX analysis. In the UV-vis absorption spectrum, maximum absorption wavelength of 2 was observed at 335 nm, which was red-shifted by 88 nm compared to that of the monomer (1).

Polymer reactions of 2 with aryl boronic acids by Suzuki-Miyaura coupling were also investigated. For example, phenylated polybromothiophene (3-Ph) was obtained in a >99% yield by the reaction of 2 with phenyl boronic acid in the presence of a catalytic amount of Pd(PPh3)4. The phenylation proceeded in a 90% efficiency as estimated by 1H NMR spectroscopic analysis. The Mn and M
w/M
n of 3-Ph were estimated to be 14,000 and 2.7, respectively, by SEC. In the UV-vis absorption spectrum, maximum absorption wavelength of the phenylated polymer (3-Ph) was observed at 365 nm, which was red-shifted by 30 nm compared to that of the polybromothiophene.

Figure 1
(Invited) Engineering of Electrochemical Interface for Highly Sensitive Biomolecular Detection: From Macro to Small Molecules
Authors: Shin Jae Hwan , Park Jong Pil
Published: December 2024

Current diagnostic methods for detection of various cells or biomarker proteins take a long time to achieve reliable outcomes and does not recognize the association between genetic variation and diversity by using nucleic acid or antibody as common recognition element. Whole antibodies are large in size and relatively expensive to produce in mammalian cells. In contrast, small affinity peptides can be created synthetically in a reliable and cost-effective manner. Thus, they can be used in a wider variety of sensing paradigms including peptide-based electrochemical sensors for high-throughput capture and detection of biomarkers in a miniaturized device format.

In this talk, we will be showing a peptide-based electrochemical biosensor that could detect virus or biomarker protein. The identified peptide-displaying phage clones and phage-free synthetic peptides were characterized using enzyme-linked immunosorbent assays and electrochemical analysis. To create more advanced sensor system, we fabricated novel functional electrodes, for example, nickel oxide (NiO)–reduced graphene oxide (rGO)/MXene, TA-PEI-graphene oxide and other nanocomposites. It was observed that developed sensing systems were capable of highly sensitive and specific detection of their corresponding target molecules with lower detection limit, better binding constant and recovery. More detailed results of protein detection will be also presenting in this talk.
(Keynote) Biologically Targeted Janus Synapse between Ultramicroelectrode and Primary Neuron
Authors: Cho Wonkyung , Oh Min-Ah , Yoon Sun-heui , Shin Chang Il , Jung Minji , Chung Taek Dong
Published: December 2024

Seamless neural interfaces conjoining neurons and electrochemical devices hold great potential for highly efficient signal transmission across neuronal systems and the external world. Signal transmission through chemical sensing and stimulation via electrochemistry is remarkable because communication occurs through the same chemical language of neurons. One promising approach is a synaptogenesis-involving method, which offers an opportunity for synaptic signaling between these systems. Janus synapses, one type of synaptic interface utilizing synaptic cell adhesion molecules for biotic-abiotic interface construction, possess unique features that enable the determination of location, direction of signal flow, and types of neurotransmitters involved, promoting directional and multifaceted communication. Such unique synaptic interfaces can directly exchange signals to and from neurons, in a similar manner to that of natural chemical synapses. In this talk, I summarize developments to improve the interface between neurons and electrodes by targeting neurons or sub-neuronal regions including synapses. Furthermore, recent progress in electrochemical neurosensing and iontronics-based chemical delivery made by my group is introduced. It includes the first successful establishment of Janus synapses between primary dopaminergic (DA) neurons and abiotic substrates using a neuroligin-2 (NLG2)-mediated synapse-inducing method. NLG2 immobilized on gold-coated microspheres can induce synaptogenesis upon contact with spatially isolated DA axons. The induced DA Janus synapses exhibit stable synaptic activities comparable to that of native synapses over time, suggesting their suitability for application in neural interfaces. By calling for DA presynaptic organizations, the NLG2-immobilized abiotic substrate is a promising tool for on-site detection of synaptic dopamine release.

References

Cho, W.; Jung, M.; Yoon, S. -h.; Jeon, J.; Oh, M. -A.; Kim, J. Y.; Park, M.; Kang, C. M.; Chung, T. D., On-Site Formation of Functional Dopaminergic Presynaptic Terminals on Neuroligin-2 Modified Gold-Coated Microspheres, ACS Appl. Mater. Interfaces, 2024, 16(3), 3082-3092.

Cho, W.; Yoon, S. -h.; Chung, T. D., Streamlining the interface between electronics and neural systems for bidirectional electrochemical communication, Chem. Sci., 2023, 14, 4463-4479.

Han, S. H.; Kim, S. I.; Oh, M. -A.; Chung, T. D., Iontronic analog of synaptic plasticity: Hydrogel-based ionic diode with chemical precipitation and dissolution, Proc. Natl. Acad. Sci. USA, 2022, 120(1), e2211442120.

Figure 1
(Invited) Novel Biosensing Platform Based on Image Analysis of Rotational Diffusion of Probe-Modified Janus Particles
Authors: Sakamoto Hiroaki
Published: December 2024

Infectious diagnosis of high-risk viruses and pathogenic bacteria is made by PCR testing. RNA virus testing is performed through multiple steps of sample collection, RNA extraction, reverse transcription, and amplification by PCR. Present methods are problematic due to the length of testing time and complexity of the operation.

In this study, we focus on the rotational Brownian motion of probe-modified particles and develop a new biosensor that is specific, quick, and simple to detect target DNA/RNA by photographing the rotational Brownian motion of probe-modified particles with a microscope and analyzing the diffusivity, which is the degree of the motion(Fig. A). The Stokes-Einstein-Debye equation, which considers the rotational motion of particles in solution, shows that the rotational diffusivity of particles is inversely proportional to the third power of the particle diameter when the ambient temperature and viscosity of the medium are controlled. In the case of Janus particles, which emit fluorescence only on half their surface, the rotational diffusivity corresponds to the correlation time, which is the correlation intensity per elapsed time of the flashing signal obtained from the rotational Brownian motion of the particles. Based on the above principle, we conducted experiments and found that under the presence of target RNA, Janus particles capture RNA, which leads to the formation of Janus particle-RNA complexes and an increase in particle volume, which in turn leads to an increase in correlation time (Fig. B). Also, the correlation time of the target RNA-Janus particle complex increases with an increase in the target RNA concentration (Fig. C). Furthermore, it was confirmed that the sensitivity and specificity of this sensor reached 85% and 100%, respectively. Since the correlation time can be measured only by microscopic observation and does with no amplification, this sensor is expected to be a simple and rapid detection.
(Invited) Wearable Electrochemical Biosensors for Continuous Biomarker Monitoring in Daily-Life
Authors: Kim Jayoung
Published: December 2024

Wearable biosensors represent a promising opportunity to monitor human physiology through dynamic measurements of (bio)chemical markers in bio-fluids such as sweat, tears, saliva, and interstitial fluid in continuous and non-invasive way. Such new platforms can thus offer real-time (bio)chemical information toward a more comprehensive view of a wearer’s health, performance, or stress at the molecular level in daily life. Continuous biomonitoring addresses the limitations of traditional invasive blood testing and provides the opportunity for early diagnostic and therapeutic interventions. My talk will focus on developing wearable electrochemical biosensors towards non-invasive health monitoring opportunities and evaluating the potential impact of such wearable point-of-care devices on our daily life and clinical settings. It will cover various types of salivary, sweat and tear fluid based wearable biosensors utilizing mouthguard, tattoo patch, and contact lens form-factors. Significant effort have been made on developing enzymatic electrochemical sensors for continuous metabolite monitoring towards healthcare in daily-life or managing diabetes like chronic disease. Recently, we demonstrated personalization strategy for accurate estimation of blood glucose utilizing non-invasive biofluids. Lastly, the talk will also cover the latest efforts on developing stress hormone (cortisol) monitoring wearable sensors, focusing on nanoscale molecularly imprinted polymer via quantum electrochemical detection.
(Invited) Electrochemical Control of Microliter-Scale Fluids Enables Innovative Insulin Pump Technology for Diabetes Management
Authors: Shin Woonsup , Zhu Enhua
Published: December 2024

Electrochemistry is known to be a key transducing technology between chemical energy and electrical energy. Electroosmosis is a phenomenon which the fluid moves upon applying electric field through capillary or porous ceramic membrane. This is a rare example where electrochemistry is utilized for a mechanical transducer. Electroosmotic pumps are the simplest one, consisting of two electrodes separated by a porous membrane. We developed a non-gassing electroosmotic pump, which do not use the traditional platinum electrode and made the pump system stable and efficient. Additionally, we have introduced plate-type electrooscmotic pump (P-EOP®), which enables battery-operable pumps with low power consumption and precise control over microliter-scale fluids. Utilizing this technology, we have constructed an insulin patch pump measuring just 11 mm in thickness and weighing 20 g, yet containing a substantial 300-unit (3 mL) insulin reservoir. Compared to conventional patch pumps with 200-unit (2 mL) insulin reservoirs, our design offers a significant reduction in both thickness and weight. This innovation holds significant promise for enhancing the quality of life for individuals with diabetes who require regular insulin administration.
Neutron Imaging of Lithium Batteries
Authors: WANG Wei , Liu Qi
Published: December 2024

The improvement of industrial batteries is a major source of power for the development of the electric vehicle market. The ever-expanding electric vehicle market has increasingly high requirements for battery life and safety. At present, the power battery on the market is mainly lithium-ion batteries. Among them, as assuming the role of energy transmission, the behavior of Li/Li+ is inseparable from the performance of the battery. During the cycle of the battery, part of the lithium will lose its activity and no longer participate in the electrochemical reaction, which directly leads to the attenuation of the battery capacity. The lithium growing on the surface of the negative electrode has dendrites, which has the potential to puncture the diaphragm and cause the safety problem of battery short circuit. In addition, limited to the capacity of existing batteries, there is an urgent need to develop safe and efficient battery fast charging technology. The US Department of Energy's requirement for fast charge technology is to reach 80% of the normal battery charge capacity in 10-15 minutes. However, the non-uniformity and irreversible metal lithium formation inside the battery caused by fast charging of the battery has always been a problem that needs to be solved. Therefore, the characterization and analysis of lithium deposition and electrode material heterogeneity of the recycled battery will be very helpful for us to understand the life and safety of the battery, and further promote the development of fast charge technology. Here I will presrent a work showing the application of neutron imaging on lithium batteries.
Effect of Conductive Carbon on the Cycling Performance of Dry-Processed Cathode with High Mass Loading for Lithium-Ion Batteries
Authors: Kim Hyo-Jin , Sim Hui-Tae , Oh Myungkeun , Park Ye-Eun , Kim Dong-Won
Published: December 2024

The cathode in lithium-ion batteries is conventionally produced by wet slurry process, which poses a technical challenge in manufacturing thick electrodes due to the migration of binder and conductive agent. To address these issues, interest in the dry process using polytetrafluoroethylene (PTFE) binder for electrode manufacturing is increasing. Dry process is based on the fibrillation of PTFE induced by shear force, facilitating the complete binding of electrode components. It offers the advantage of uniformly dispersing conductive agents and binders, enabling the utilization of high-loading cathodes. In accordance with the cycling progresses, especially in thick electrodes, active materials on the separator side continuously participate in oxidation/reduction reactions, while those on the current collector side contribute less to these reactions. This highlights the crucial role of conductive agents in optimizing electrode performance. In this study, we explore the influence of the morphology of conductive carbon on the cycling performance of dry-processed cathode in lithium-ion batteries. In contrast to conductive carbon that establishes electron pathways through point-contact, the fibrous structure of conductive carbon promotes line-contact, thereby ensuring longer and more uniform electron pathways within the high-loading electrode. It facilitates the comprehensive utilization of active materials, even at a distance. Consequently, fibrous carbon achieved higher electrical conductivity, leading to enhanced electrochemical performance. The high mass-loaded LiNi0.8Co0.1Mn0.1O2 cathode with areal capacity of 8 mAh cm-2, fabricated through a dry process using 1 wt.% PTFE exhibited good electrochemical performance. XPS and XRD analyses were conducted to investigate the deterioration of active materials, and the morphology of active materials was compared by SEM analyses.
A Spherical LiFePO4/Carbon Nanotubes/Binder Composite as a Cathode Material for High Performance of Lithium-Ion Batteries
Authors: Yoon Jihee
Published: December 2024

As the global demand for electric vehicles continues to rise, the safety of electric vehicles, particularly concerning the risk of fires induced by battery degradation, is increasingly recognized as a critical issue. Current production batteries utilize cathode materials with high nickel content (>80%) in order to develop electrodes with high-energy-density. However, these NCM cathode materials, due to their structural instability, can undergo changes during the charge-discharge processes of the battery, making them susceptible to degradation in high-temperature environments or during charging-discharging, thereby posing a fire risk. Therefore, many battery companies are currently focusing on advancing research into utilizing LiFePO4 (LFP) cathode materials. LFP possesses a stable olivine structure, resulting in fewer structural changes during charge and discharge compared to NCM cathode materials. Consequently, LFP batteries offer high durability and a lower risk of fires, enhancing the safety of electric vehicle batteries. Additionally, the raw materials used in LFP production are relatively cost-effective, contributing to lower battery manufacturing costs.

However, LFP has relatively lower energy density and smaller particle sizes than NCM, limiting its ability to increase battery capacity. It also exhibits lower electrical conductivity, which can have disadvantages in terms of electrochemical properties including battery resistance and rate capability. To overcome these limitations, various research studies have been conducted, such as controlling particle size and applying surface coatings to the active material.

In this study, spherical LFP/carbon nanotubes (CNTs)/binder composites were developed to improve cell performance. We synthesized LFP/CNTs/binder composites through the spray-drying method and studied the morphologies of granules according to spray drying conditions. We particularly focused on achieving a well-distributed spherical microstructure to improve the electrode modulus, including electrode density and tortuosity. LFP with well-embedded CNTs and binder exhibited excellent cell lifespan characteristics even at high energy density and showed good performance at high C-rates.
Characterisation of Electrochemical Systems from Periodic Chronoamperometry Signals Using Computational Tools
Authors: Kloyer Leopold , Fisher Adrian C
Published: December 2024

Electrochemical systems are complex, involving various chemical and physical processes (e.g. electron transfer reactions, diffusive and convective mass transfer, charge transfer processes). In most cases, electrochemical systems are summarised using simple signals (e.g. amperometric or potentiometric signals), which do not, however, adequately capture their complexity. These mostly unidimensional signals are usually insufficient to facilitate the full understanding of the electrochemical system and its underlying, simultaneously occurring processes.

Established electroanalytical methods are commonly utilised to characterise specific (electro-) chemical and physical processes of electrochemical systems (e.g. potentiometry, amperometry/voltammetry, electrochemical impedance spectroscopy, etc.). Despite the usefulness of these traditional electroanalysis techniques, they are often restricted to the analysis of a very specific set of system characteristics and parameters. Moreover, the experimental nature of these techniques, usually requiring a specific protocol, sets limits to their employment for on-line measurements of industrial electrochemical systems (e.g. reactors, fuel cells etc.).

To avoid these limitations, a new alternative approach to understanding and characterising electrochemical systems is proposed. Computational techniques have the potential to extract various system parameters from periodic chronoamperometry signals of electrochemical systems. Such techniques include methods that are commonly used in chemometric investigations in addition to other modern signal processing tools.

Early findings from this ongoing study include the separation of Faradaic and non-Faradaic current contributions from a variety of simulated chronoamperometric signals. Moreover, qualitative sensitivity studies appear promising for the subsequent quantitative recovery of multiple parameters from stagnant and hydrodynamic electrochemical systems (e.g. capacitance, resistance).

As a consequence, this novel computer-aided approach can pave the way for real-time analyses of electrochemical applications. Furthermore, this strategy will likely reduce the need for specific electroanalytic experiments to determine certain parameters. Instead, complex electrochemical systems and their underlying chemical and physical processes have the potential to be characterised from simple, continuous chronoamperometric signals by means of computational techniques.
Suppression of Heat Generation during Rapid Charge and Discharge of LIB by Adding VGCF-H to the Cathode
Authors: Kishi Mayuko , Inose Tsuyoshi , Mori Takashi , Harada Daisuke , Ito Yuji , Takeda Akifumi
Published: December 2024

Lithium-ion batteries (LIB) are widely used in various fields such as xEV, mobile devices and other applications as essential power sources due to their high voltage range of over 4V and their ability to operate over a wide temperature range. On the other hand, various factors cause heat generation in the charging and discharging reaction, and the heat generation increases as the current increases. Since heat generation leads to degradation in LIB, thermal management has become a challenge. The conductive additive VGCF-H is a graphitized carbon fiber synthesized by a vapor phase method with a low specific surface area and high crystallinity. We have previously proposed the addition of VGCF-H to the cathode as a means to improve the cycle life and reduce the resistance of LIB. This study aims to propose conductive additives including VGCF-H and to clarify the mechanism of characteristic expression from the perspective of thermal management during rapid charge and discharge.
Suppression of Loss of Fast Charging Capability in Ni-Rich Cathode By Microstructural Modification
Authors: Kim Myoung-Chan , Park Nam-Yung , Sun Yang-Kook
Published: December 2024

Fast charging technology for electric vehicles (EVs), which promises rapid charging times similar to refueling conventional vehicles, holds promise but encounters hurdles due to kinetic issues within lithium-ion batteries (LIBs). These issues include both kinetic and thermodynamic challenges within batteries, resulting in restricted utilization of active materials, Li plating, excessive heat generation, and accelerated capacity degradation.1 Efforts to tackle issues associated with fast charging have predominantly concentrated on modifying the Li salts in the electrolyte or the structure and surface/interface of the anode materials.However, compared to the electrolyte or anode materials, the importance of the cathode in relation to fast charging has not been significantly highlighted. Because properties such as the energy density, thermal stability, and rate performance of LIBs are largely determined by the cathode material, 2 understanding the characteristics of the cathode under high-current-density conditions is essential to comprehensively understand fast charging.

In this study, the mechanism responsible for the loss of fast charging capability of Ni-rich cathodes during prolonged cycling is examined via a comparative analysis of Ni-rich cathodes exhibiting different microstructures. The results demonstrate that microcracks and subsequent cathode degradation notably compromise the fast charging capability over extended cycling periods. Formation of thick rocksalt impurity phases throughout the particles due to electrolyte infiltration via microcracks leads to limited kinetics of Li+ ions, resulting in electrochemically inactive regions under high-current conditions, hence leading to the loss of fast charging capability. Therefore, preventing microcrack formation by microstructural modification is imperative to ensure stability in fast charging capability. These findings underscore the need to comprehensively understand the degradation of the cathode during extended cycling, particularly from the perspective of the kinetic loss of utilizable Li+ ions at high currents, rather than just the loss of capacity.

Reference
s
:

[1] Y. Liu, Y. Zhu, Y. Cui, Nat. Energy, 2019, 4, 540.

[2] H.-J. Noh, S. Youn, C. S. Yoon, Y.-K. Sun, J. Power Sources, 2013, 233, 121.
Utilizing Ionic Liquid Mixtures to Modify Lithium Solvation Chemistry and Electrolyte Properties
Authors: Biddinger Elizabeth J.
Published: December 2024

Ionic liquids are appealing as electrolytes because of their wide electrochemical windows, moderate conductivities, minimal flammability and ability to tune the structure-property relationships. Shortcomings with the use of ionic liquids in lithium-based batteries are due to poor lithium ion transport, lack of formation of a stable solid electrolyte interphase (SEI) and limited lower temperature operations. To overcome the shortcomings, ionic liquids can be mixed with co-solvents or additives. SEI formers, co-solvents for lowering melting points and increasing conductivities, and agents to modify the interactions with lithium can all be introduced to the ionic liquid electrolytes. In the work to be presented here, the strategy of mixing solvate ionic liquids (Li(G4)TFSI) with task-specific pyrrolidinum-based ionic liquids that have short polyether side chains will be presented. Li(G4)TFSI is a solvate ionic liquid with an equimolar ratio of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and tetraethylene glycol dimethyl ether (G4). Li(G4)TFSI with an oxygen-to-lithium ratio of 5 ([O]/[Li+]=5), has a high lithium concentration and improved low temperature liquid range compared to traditional ionic liquids. By adding the task-specific ionic liquids with solvate ionic liquid analogous side chains, the properties of the electrolyte can further be tuned while aiming to keep the anion from solvating the Li ion which hinders its transport. The length of the polyether groups on the ionic liquid were varied to have constant ratios of ionic liquid:LiTFSI:G4 or to maintain a constant [O]/[Li+] ratio. The influence of the anion utilized with the ionic liquid was also investigated. The physical and electrochemical characteristics of the ionic liquid mixtures were evaluated to better understand how key properties and solvating power affect reversible lithium deposition and stripping across a range of temperatures. Through the use of ionic liquid-based mixtures, many of the desirable properties of the ionic liquids can be retained while the undesired properties of the ionic liquids can be mitigated, making for more favorable electrolytes.
(Physical and Analytical Electrochemistry Division Max Bredig Award in Molten Salts and Ionic Liquid Chemistry Address) Unexpected Energy Applications of Ionic Liquids
Authors: MacFarlane Douglas Robert
Published: December 2024

Ionic liquids (ILs), Ionic liquid Analogues (ILAs) and Organic Ionic Plastic Crystals (OIPCs) are finding a wide range of applications in energy related applications. The advantages of ILs as Lithium battery electrolytes have been explored for many years. In more recent times this has expanded to include IL/ILA type electrolytes for sodium, magnesium and potentially aluminium-based batteries. Other electrochemical applications include thermo-electrochemical cells and as electrolytes in ammonia producing electrolysis cells. Beyond electrochemistry there is great interest in ILs as phase change materials for the storage of thermal energy, including in a novel heat-pump based device known as the Carnot Battery.

Also emerging are a number of “mixture” systems related to ILs that have modified or enhanced properties; these we broadly describe as Ionic Liquid Analogues. In many cases these analogues have lower cost and improved sustainability characteristics than pure ILs.

One the key drivers of further development of ionic liquid chemistries, currently, is the need to focus on sustainability and the circular economy, both in regard to the ionic liquid components themselves as well as their impact on the recycling or repurposing of the bigger system in which they are employed. For example, the growing concern regards PFAS compounds is rendering some ionic liquid ions unsuitable and manufacturers unlikely to continue supplying them.

Many of these applications have emerged in the last decade or so in the period since we wrote a paper entitled “Energy Applications of Ionic Liquids”.1 To reflect on these, somewhat unheralded, developments in emergent fields, we have very recently published an update on that paper.2 This, and the many papers it reviews, forms a key basis for this talk.

(1) MacFarlane, D. R.; Tachikawa, N.; Forsyth, M.; Pringle, J. M.; Howlett, P. C.; Elliott, G. D.; Davis, J. H.; Watanabe, M.; Simon, P.; Angell, C. A. Energy applications of ionic liquids. Energy Environ. Sci.
2014, 7 (1), 232-250, DOI: 10.1039/C3EE42099J.

(2) Karolina Matuszek, S. P., Alina Brzęczek-Szafran, Binayak Roy, Saliha Saher, Jennifer M. Pringle, Douglas R. MacFarlane. Unexpected Energy Applications of Ionic Liquids. Adv. Mater.
2024. DOI: 10.1002/adma.202313023.
Utilization of Cellulose/Ionic Liquids Solution for Additive Manufacturing
Authors: Reichert W. Matthew Matthew , Wright Janiya , Duranty Edward R.
Published: December 2024

Additive manufacturing has gathered increased attention in a variety of research areas due to its ability to create complex structures rapidly using low-cost materials. An emerging area of interest in additive manufacturing research is the utilization of biopolymers as print materials. Advantages to using biopolymers for additive manufacturing are their sustainability compared to traditional petroleum-based polymers, decreased impact on the environment, and ability to be recycled with little degradation of the material. The ability of ionic liquids (ILs) to dissolve a range of biopolymers has advanced research in this area, especially with using cellulose. One printing technique that is well suited for the printing of cellulose solutions is thick paste extrusion, a technique usually incorporating ceramic pastes. This technique is ideal for printing cellulose/IL solutions due to its ability to push high viscosity solutions through a nozzle. In this investigation, a ZMorph Fab 3D printer with a thick paste extrusion attachment was used to print a simple triangle shape. In order to determine the printability of the cellulose solution with this technique several factors were studied, including solution viscosity, print speed, print bed adhesion, and print height. In tuning these parameters to optimize printing, one can begin to print more complex objects.
Quantification and Correction of Impedance Effects on Square Wave Voltammetry for High-Concentration Soluble-Soluble Reactions
Authors: Shaheen Nora A. , Guo Jicheng , Hoyt Nathaniel C.
Published: December 2024

Molten salts are of interest for a wide variety of applications including nuclear energy, metal electrorefining, and concentrated solar power. In situ monitoring of species within molten salts is important to ensure operation is well-controlled. Electroanalytical techniques such as square wave voltammetry (SWV) and linear sweep voltammetry (LSV) offer approaches toward precise measurement of species’ fundamental properties (e.g. diffusion coefficient, number of electrons transferred, etc.). However, several publications have reported deviations between data collected through SWVs and LSVs. In this talk, we explain the discrepancy in the context of SWV using molten chloride systems with dissolved metal ions. Theoretical simulations coupled with experimental data confirm the divergence of property measurements can be attributed to impedance effects. Using our approach, the diffusion coefficients, solubility limits, and concentration measurements at high concentrations of metal ions extracted using SWV converged with literature reports using LSVs.
Deciphering Structure and Dynamics of Molten Salts
Authors: Ivanov Alexander
Published: December 2024

Enhancing the energy conversion and storage applications afforded by emerging molten salt-based technologies requires a fundamental understanding of the complex interplay between structure and dynamics of the ions in the high-temperature media. This not only makes characterization difficult, but also renders it highly questionable whether conventional in-lab methods of analysis typically used for solids could be applied to the molten state. Our research seeks to provide atomic-level insights into the ionic correlations in high-temperature molten inorganic salts by applying synchrotron X-ray and neutron scattering coupled with ab initio molecular dynamics simulations and reverse Monte-Carlo modeling. A thorough analysis paints a more complex picture than previously understood, with the formation of ionic chains even at high temperatures and surprising similarities with aqueous solutions, suggesting a possible universal connection between local structural changes and physical properties of liquids despite the drastically different types of chemical bonding. We discuss how the total scattering approaches could help understand the aggregation phenomena and transport in molten salts, with pertinence to novel electrochemical processes.
Electrochemical Formation of Layered Organo-MnO2 and Its Application to Selective Iodide Recovery
Authors: Yoshida Wataru , Tanaka Saki , Nakayama Masaharu
Published: December 2024

We have fabricated a thin film of multilayered MnO2 whose interlayer is occupied with cetyltrimethylammonium cations (CTA+), using a simple anodic approach. X-ray diffraction (XRD) analysis and Fourier-transform infrared spectroscopy (FTIR) revealed that the deposited film possesses a layered structure of MnO2 and CTA molecules. The obtained film, CTA-intercalated layered MnO2 (CTA/MnO2), was applied as a sorbent toward iodide (I–). CTA/MnO2 film did not show significant iodide sorption from artificial seawater solution containing 0.1 mM NaI, but effectively sorbed iodide anions by excluding Ca2+ and HCO3
– from the artificial seawater solution, even in the presence of large amount of Cl– and SO4
2– anions. This indicates that Ca2+ and/or HCO3
– inhibit the uptake of iodide ions into the interlayer of CTA/MnO2. The sorption isotherm was in good agreement with the Langmuir type, and the maximum sorption capacity was estimated to be 213 mg/g-MnO2. Sorption of iodides into the interlayer of MnO2 film was evidenced by X-ray photoelectron spectroscopy (XPS). The results suggest that the sorption of iodide by the CTA/MnO2 film occur via not only simple ion-exchange, but also hydrophobic interaction between the interlayer organic phase of the film and iodide ions in solution. The layered structure of the CTA/MnO2 composite remained unchanged after the sorption experiment.

Figure 1