bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrogeneration of Oxygen-Centered Radicals from N-Alkoxyphthalimides and Their Use in a Remote C-H Functionalization for 5,5-Spirocycles Construction
Authors: Romero Ibañez Julio , Chicas-Banos Diego Francisco , Colindres-Díaz Edgar Alan , Sartillo-Piscil Fernando , Frontana-Uribe Bernardo Antonio 
Published: December 2024

Oxygen-centered radicals, also known as alkoxyl radicals, are highly reactive species that have been considered useful synthetic intermediates.[1] Considering their synthetic accessibility, stability, and particular reactivity, N-alkoxyphthalimides (NAPIs) offer a practical avenue for generating these radicals under mild conditions, such as via electrochemical means.[2] Recent studies have demonstrated the effectiveness of N-benzyloxyphthalimides in accessing benzylic-carbonyl compounds through electrochemical reduction.[3] To modulate the conversion of NAPIs to O-centered radicals under electroreductive conditions, it was studied and transferred the reported mechanistic insights of photocatalytic redox conditions to an electrochemical approach by employing the Hantzsch ester and rapid alternating polarity electrolysis.[4,5] The electrogenerated O-centered radicals from NAPIs were then explored for their utility in remote C-H allylation and the synthesis of 5,5-spirocycles which represent important structural motifs of diverse natural products, including Cephalosporolides.
[1] A.S. Budnikov, I.B. Krylov, A.V. Lastovko, B. Yu, A.O. Terent’ev, Nalkoxyphtalimides as versatile alkoxy radical precursors in modern organic Synthesis, Asian J. Org. Chem. 11 (2022), https://doi.org/10.1002/ ajoc.202200262.
[2] M.A. Syroeshkin, I.B. Krylov, A.M. Hughes, I.V. Alabugin, D.V. Nasybullina, M. Y. Sharipov, V.P. Gultyai, A.O. Terent’ev, Electrochemical behavior of Noxyphthalimides: cascades initiating self-sustaining catalytic reductive N–O bond cleavage, J. Phys. Org. Chem. 30 (2017) 1–15, https://doi.org/10.1002/poc.3744.
[3] D.F. Chicas-Baños, M. Lopez-Rivas, F.J. Gonzalez, F. Sartillo-Piscil, B.A. Frontana-Uribe, Access to carbonyl compounds via the electroreduction of Nbenzyloxyphthalimides: mechanism confirmation and preparative applications, Heliyon 10 (2024) e23808, https://doi.org/10.1016/j.heliyon.2023.e23808.
[4] J. Zhang, Y. Li, F. Zhang, C. Hu, Y. Chen, Generation of alkoxyl radicals by photoredox catalysis enables selective C(sp3 )-H functionalization under mild reaction conditions, Angew. Chem. Int. Ed. 55 (2016) 1872–1875, https://doi.org/ 10.1002/anie.201510014.
[5] J. Romero-Ibañez, D.F. Chicas-Baños, F. Sartillo-Piscil, B.A. Frontana-Uribe, Highly efficient electrogeneration of oxygen centered radicals from N-alkoxyphthalimides employing rapid alternating polarity (RAP) electrolysis. Transferring the photoredox catalytic conditions to organic electrosynthesis, Curr. Res. Green Sustain. Chem. 8 (2024) 100404, https://doi.org/10.1016/j.crgsc.2024.100404.

Figure 1
Electrodes, Mediators, and New Opportunities for Selectivity in Chemical Reactions
Authors: Moeller Kevin D 
Published: December 2024

Recently, we showed that it is possible to take advantage of confinement strategies developed on microelectrode arrays to introduce selectivity into a solution phase chemical reaction. This was accomplished by controlling where in a reaction flask the reaction occurred and then manipulating that environment. This discovery opens up a series of new opportunities for synthesis where the course of a chemical reaction is controlled not by the reaction itself but rather by a remote binding event. In the talk to be given we will begin to explore these ideas along two pathways.
In the first, we will examine how an electrode surface can be used to control the course of a transition metal catalyzed cross coupling reaction by its interaction with remote functionality in a substrate. Specifically, we will look at how the overall shape and charge of a molecule can be used to introduce selectivity into the reactions in a manner not possible through reagent control alone.
Second, we will talk about “platform” reactions that are allowing us to begin examining routes for introducing absolute stereochemistry into electrochemical cyclization reactions. This discussion will focus on the reactions themselves, mechanistic details that allow for their optimization, and new ways to mediate the cyclization reactions so that new handles for controlling stereochemistry can be utilized.
In both stories, we will focus on how the unique attributes of electrochemistry can be utilized to influence reactions of interest to the larger synthetic community.
Granule-Design Technology of Electrode-Composite for Reducing Electric Resistance of Lithium-Ion Battery
Authors: Yokota Maria , Tuerxun Feilure , Akimoto Yusuke , Matsunaga Takuro 
Published: December 2024

We are facing a problem of global warming due to emission of greenhouse gases such as carbon dioxide. That promote people’s preference for electric vehicles causing increase of demand for batteries. Development of high-performance batteries for automotive applications is underway around the world. There, important issues to be solved include increasing speed of batteries’ production, improving the batteries’ performance, reducing greenhouse-gas emissions in the production processes. Here, we discuss our idea to achieve all three missions.
Our approach to the problems is dry processing of electrode sheeting and electrode-structure control. We used granulation by spray drying as a means of controlling the electrode structure. During granulation by spray-drying, we controlled the arrangement of conductive aid and binder particles to create a localized (phase-separated) structure. The core is active-material-rich, and the shell is conductive-aid-rich. When the particles packed as electrodes, the shells of the granules were automatically connected to each other, then the conductive aid formed network structure in the electrodes. The electrode achieved reducing the electric resistance.
Another reason for preparing granules using spray drying prior to electrode sheeting is to improve the flowability of the powder. Since the granules are large and their shapes are rounded, fluidity as a granular bulk be much high like sand on a beach. Then we spread them on metallic foil by doctor blade like slurry coating. That makes the production speed be high. In addition, our granules include polymer as binder, the granular-spread sheet can be stuck on the foil by heated roll press without solvent. Details of the deposition method and electrochemical evaluation results will be discussed on the day of the presentation.
Parameter Identification of Pseudo-Two-Dimensional Model for Lithium-Ion Batteries with Silicon/Graphite Composite Electrodes
Authors: Ha Jinho , Kim Sanghyun , Jun Gwang Hoon , Koh Dong-Wook , Choi Jung-Il 
Published: December 2024

In this study, we assess the performance of lithium-ion batteries (LIBs) equipped with silicon/graphite composite electrodes and estimate the electrochemical properties of each constituent material. We employ a composite electrode model integrated into the conventional pseudo-two-dimensional (P2D) model to simulate the electrochemical dynamics of the battery. First, the accuracy of the numerical model is validated by comparing its voltage predictions with existing experimental data. The model successfully captures the voltage characteristics of LIBs across various C-rates. Additionally, the interaction effects between silicon and graphite within the composite electrode are validated by comparing them to previous simulation results. Specifically, the reactivity of silicon and graphite, which varies with the operating voltage range, is accurately assessed under various operating conditions.
Parameter estimation for the electrochemical model is performed using a genetic algorithm. Ten parameters significant to the electrochemical performance of each material are selected, considering their physical significance and the feasibility of experimental validation. These parameters are optimized by minimizing a fitness function defined by the relative errors between the experimental and simulated voltage, utilizing 1/3C discharge and pulse data from different states of charge (SOCs). The simulated voltages with the optimized parameters align well with the experimental data, accurately representing both the constant-current discharging voltage and the voltage dynamics during pulse application and removal. This alignment confirms that the estimated parameters effectively characterize the electrochemical behavior of LIBs with the composite electrode.
A comparative analysis of parameter identification using only constant-current discharging data versus a combination of constant-current and pulse data reveals significant variations in the distribution of estimated values. Parameters derived solely from constant-current data inadequately fit the pulse data, highlighting the necessity of incorporating diverse data types for reliable parameter estimation.
The methodology proposed in this work provides a robust framework for evaluating the electrochemical properties and performance of LIBs featuring silicon/graphite composite electrodes. This approach offers a detailed assessment of the material-level properties by identifying critical electrochemical parameters. Future work will focus on developing an efficient experimental protocol for parameter estimation, employing sensitivity analysis and case studies across different voltage profiles to ensure reliable parameter determination.

Figure 1
Fluorinated Azide Enables Fully Crosslinked Ceramic-Coated Separators for Advanced Li-Ion Batteries
Authors: Choi Seungyeop , Hassan Syed Zahid , Roh Youngjoon , Seo Jun Pyo , Chung Dae Sung , Lee Yong Min 
Published: December 2024

Lithium-ion batteries (LIBs) have become widely adopted for energy storage due to their high energy density and long cycle life. However, the safety of LIBs under severe operating conditions remains a pressing issue. In this context, ceramic-coated separators (CCSs) are critical in enhancing LIB safety by reducing the risk of internal short circuits. Conventional methods for improving the thermal stability of CCSs have relied on combining ceramic particles with polymer binders. These techniques, however, face limitations in significantly enhancing the thermal stability of the ceramic coating layer (CCL), particularly as efforts to minimize the thickness and areal mass of the CCL aim to elevate the energy density and power performance of LIBs.
For this purpose, several strategies have been investigated to enhance the thermal stability of ceramic-coated separators (CCSs). One promising approach involves the incorporation of polymer binder with high melting points within the CCL, ensuring improved resilience to high temperatures [1]. In addition, our research group reported the effect of crosslinking structures between ceramic particles and polymer binder on the adhesive strength and thermal stability of the CCL [2]. Nevertheless, as the energy density of LIB increases, more comprehensive strategies must be developed.
Herein, we introduce a photo-crosslinking strategy employing a novel fluorinated azide crosslinker, capable of reacting with C-H groups in polymer chains under UV irradiation. After coating the CCL slurry composed of ceramic particles, polymer binder, and fluorinated azide crosslinker on the separator, short UV irradiation forms comprehensive crosslinking structures within the CCL. Crosslinking points occur not only within the separator substrate but also between the substrate and the polymer binder, as well as among the polymer binders present in the CCL. As a result, the thermal stability and adhesive strength of the CCS are significantly improved when compared to those of the non-crosslinked one. Moreover, a LiNi0.6Co0.2Mn0.2O2/graphite full cell incorporating the crosslinked CCS demonstrates a cycle life comparable to that of the non-crosslinked one.
References

A high-temperature stable ceramic-coated separator prepared with polyimide binder/Al2O3 particles for lithium-ion batteries,
J. Memb. Sci.
, 517 (2016) 91-99

Highly improved thermal stability of the ceramic coating layer on the polyethylene separator via chemical crosslinking between ceramic particles and polymeric binders,
Chem. Eng. J.
, 433 (2022) 134501
Enhancing High-Performance for the Lithium-Ion Battery of Si/G Anode Via an Effective Additive Strategy
Authors: Jeong Woojin , Yang Subi , Lee Seungho , Lee Juhyun , Han Seungmin , Chun Jinyoung , Choi Junghyun 
Published: December 2024

Since the first commercialization of lithium-ion batteries (LIBs), LIBs have become an important power source for wireless electronics, electric vehicles (EVs), and other renewable energy storage systems due to their high energy density and operating voltage. The higher energy density of LIBs indicates that the electrode material can store more energy per unit mass or volume. Currently, with the high capacity demands of EV batteries and the use of high-capacity LIBs in a variety of devices, anode material capacity requirements are also rising rapidly. However, graphite, the most widely used anode material in commercial LIBs, has challenges in enhancing the energy and power density of LIBs due to its limited theoretical specific capacity (372 mAh g-1) and restricted rate capability. Hence, most battery industries have focused on forming graphite-silicon composites through the blending of silicon (Si) and graphite.
Si has an ultrahigh theoretical specific capacity of 3579 mAh g-1 (Li15Si4), which is roughly 10 times higher than the specific capacity of graphite, and has a low redox potential (0.4 V vs Li/Li+). However its excellent properties, the Si-based anode undergoes a severe volume expansion (up to 300 %) during the repetitive lithiation/delithiation process. The resulting physical change causes the breakdown/restoration of the solid electrolyte interphase (SEI) layer over the surface of the Si. This phenomenon causes electrolyte decomposition, degradation of Coulombic efficiency, the loss of active lithium ions, and the formation of an unstable SEI layer.
To address the inherent problems of Si, countless researches have been conducted to improve the electrochemical performance and long-term cycle stability of graphite-Si composite electrodes through nanostructure engineering, composite optimization, and surface modification. Nevertheless, graphite-Si composite electrodes continue to encounter challenges (e.g., electrode pulverization and delamination), constraining the incorporation of Si active materials into the composite. Therefore, it is imperative to devise a new graphite-Si composite for high-performance LIBs.
In this work, we used polyvinylpyrrolidone (PVP) as an electrode additive and investigated how it affects SEI components and volume expansion issues. PVP, a component of LiF and Li3N, can produce high-quality SEI in the field. We verified this via X-ray photoelectron spectroscopy(XPS). In addition, when we evaluated Li metal cells, we discovered that the electrode with PVP had better capacity retention and battery performance than the electrode without PVP, and when we reviewed full cells, we discovered that the rate characteristics were improved and volume expansion was reduced. This work explores a simple strategy for employing electrode additives to improve long-term cycle stability and high-rate performance.
Nitride-Based Sacrificial Cathode Additive for High Energy Density Lithium-Ion Batteries
Authors: Yun Dongyeon , Kim Juhwan , Hong Seung-Tae 
Published: December 2024

Lithium-ion batteries are indispensable in modern technology, powering a vast range of applications from electric vehicles to mobile devices, and are pivotal in the pursuit of sustainable energy solutions. Enhancing their energy density is of particular importance, and silicon-based anode materials are at the forefront due to their superior capacity over conventional graphite anodes. However, the use of silicon-based materials as anodes leads to substantial lithium consumption during the initial solid electrolyte interface (SEI) layer formation. Consequently, this results in a significant first cycle Coulombic efficiency gap between the conventional cathode Li(NixMnyCoz)O2 (NMC) material and the anode, leading to inefficient use of the available lithium and a failure to harness the maximum capacity of the electrode materials.
To address this irreversible capacity loss and to fully exploit the capacity of NMC cathode materials, the development of innovative sacrificial additives for prelithiation is critical. Such additives, included within the positive electrode, provide additional lithium to the anode during the initial charging cycle. Our study introduces a novel lithium nitride-based material, distinguished by its high initial compensation capacity and chemical stability in dry-air conditions. This material exhibits an impressive initial charging capacity of over 600 mA·g−1 and a minimal discharge capacity of less than 20 mA·g−1. These characteristics significantly boost the reversible capacity of a full cell that combines an NMC cathode and silicon-based anode. We will detail the synthesis, crystallographic details, and comprehensive chemical and electrochemical characterizations of this promising sacrificial cathode additive, highlighting its potential to enhance battery performance significantly.
First-Principles Study on Lithiation Process of Sio Anode for Li-Ion Batteries
Authors: Shintaku Ryoya , Tamura Tomoyuki , Nogami Shogo , Hirose Takakazu 
Published: December 2024

Lithium-ion secondary batteries (LIB) with a high energy density have been developed mainly for use in small mobile devices. In recent years, the high capacity of LIB has become important for automobile applications. One possible high-energy density solution is the use of high-capacity negative electrodes fabricated from tin, silicon, or other materials, and a-SiO materials have been already commercialized. However, a-SiO materials has the issue of capacity degradation during charge-discharge cycles. In particular, it is speculated that the structural change during charging process causes the capacity degradation, but the detail has not been clarified yet. Therefore, in this study, we clarify the local structural changes in a-SiO up to full charge using first-principles calculations.
In our previous study [1], a-SiO models were generated using classical molecular dynamics (MD) simulations with neural network potentials.
Using one of these models, we explore the lithiation process of a-SiO using first-principles calculations with SIESTA code [2]. The simplest method to obtain a-Li
x
SiO model is to melt an initial structure in which Li atoms are randomly arranged at high temperature and then cool it. But it was found that this process could not reproduce the actual charge process and Li atoms should be placed at stable sites. Therefore, we developed a computational code with which stable sites of Li atoms can be searched efficiently using Bayesian optimization.
Fig. 1 shows Li-inserted models at (a) 0%, (b) 55% and (c) 100% SoC (State of Charge). Li atoms are gradually inserted into the SiOx phase in the initial state of charging, and inserted into the Si phase over 20% SoC. These results are consistent with previous experimental results [3]. One Li6O octahedron can be seen in the model at 55% SoC, and the number of Li6O octahedra increases to five in the model at 100% SoC. The formation of Li6O octahedra during charging is irreversible, which is considered to cause the capacity degradation. To prevent capacity degradation, it is necessary to suppress the formation of these structures.

References

[1] H. Hirai et al., Phys. Rev. Materials 6, 115601 (2022).
[2] J. Solar et al., J. Phys. Cond. Matt. 14, 2745 (2000).
[3] T. Hirose et al., Solid State Inonics 304, 1 (2017).

Figure 1
Ion Transport and Solution Behavior of Polyanion-Type Li Salts in Nonaqueous Solvents
Authors: Nakagaki Hiroki , Kondou Shinji , Watanabe Masayoshi , Ueno Kazuhide 
Published: December 2024

To achieve fast charging and discharging of Li-ion batteries, it is important to improve the ionic conductivity (σ) of the electrolyte as well as the Li-ion transference number (t
Li) [1]. While nonaqueous polyelectrolyte solutions exhibit high Li-ion transference number(t
Li
= 0.81) upon immobilization of the anion on a polymer backbone, the ionic conductivity (σ = 1.3 mS cm-1) is inferior to that of conventional electrolytes (σ ~10 mS cm-1). One of the reasons for the low ionic conductivity is low dissociation degree caused by the counter-ion condensation on the polymer backbone. To gain an insight into a design strategy of polyelectrolyte-based liquid electrolytes for LIBs, we studied the effects of polyelectrolyte structure and solvent polarity on the transport properties and Li-ion solvation of the polyelectrolytes in carbonate solvents. Here, we employed two polyelectrolyte copolymers with different sequences; random copolymers of the Li salt of a weakly coordinating polyanion, poly[(4-styrenesulfonyl)-(trifluoromethanesulfonyl)amide] (poly(LiSTFSA)) with neutral comonomer unit, and poly[(4-maleimide-N-[(trifluoromethyl)sulfonyl]-benzenesulfonamide lithium salt] (poly(sa-PMI))-based alternating copolymers with neutral comonomer unit. For the random copolymers, the ionic conductivity increased as the ratio of the neutral comonomer increased. This was attributed to the suppression of counter-ion condensation and increased dissociation. The alternating copolymer solution showed higher dissociation than the random copolymers. The highest ionic conductivity was unexpectedly observed for the lowest polar mixture (such as a dimethyl carbonate rich mixture) at the highest salt concentration despite the low dissociation degree of the polyelectrolytes. A unique conduction resulting from the faster diffusion of transiently solvated Li ions along the interconnected aggregates of polyanion chains was suggested in the highly concentrated polyelectrolyte solutions in low polar solvents. A Li/LiFePO4 cell using the polyelectrolyte solution demonstrated a good charge-discharge performance and rate capability[2].
References
[1] K. M. Diederichsen, E. J. McShane, B. D. McCloskey, ACS Energy Lett., 2, 2563-2575 (2017).
[2] S. Kondou et al., ACS Appl. Mater. Interfaces, 14, 18324-18334 (2022).
Observation of Excited State-Derived Photoluminescence Decay of Organic Dye to Monitor Its Photo-Induced Charge Transfer Efficiency
Authors: Shin HyeonOh , Kwon Tae_Hyuk 
Published: December 2024

Understanding photo-induced charge transfer (PCT) is crucial for optimizing the performance of solar-powered devices like photovoltaic and photoelectrochemical cells, as PCT directly impacts their operation and overall power conversion efficiency. General assessment of PCT has heavily relied on transient absorption techniques to gauge electron transfer between the donor and acceptor. However, there is a pressing need to broaden the methods for comprehensively studying PCT.
In this study, we propose an alternative approach utilizing transient photoluminescence to observe PCT dynamics between organic dyes and redox mediators. This approach involves adsorbing various organic dyes onto Al2O3 surfaces along with redox mediators. When excited, the dyes facilitate charge separation from each other, leading to the instantaneous oxidized form of the dye and subsequent electron transfer from the redox mediator. This process results in a decrease in the photoluminescence lifetime of the organic dye. The extent of this decreases correlates with the Gibbs free energy of charge transfer, reflecting the efficiency of electron transfer between the organic dye and the redox mediator. Our findings introduce an alternative avenue for studying PCT, offering insights that are pertinent to various fields including photovoltaics, optoelectronics, and photocatalysis.

Figure 1