https://scholar.dgist.ac.kr/handle/20.500.11750/13676 2026-04-04T14:43:27Z 2026-04-04T14:43:27Z Akter Shanjida Mariam Afira Lim, Minhong Lee, Hongkyung Choe, Seungho https://scholar.dgist.ac.kr/handle/20.500.11750/59990 2026-02-09T15:10:48Z 2025-09-30T15:00:00Z

Title: Decoding Diluent-Driven Solvation Dynamics in Locally Concentrated Ionic Liquid Electrolytes Author(s): Akter Shanjida; Mariam Afira; Lim, Minhong; Lee, Hongkyung; Choe, Seungho Abstract: The interplay between lithium salts and anions critically influences the electrochemical and physicochemical properties of locally concentrated ionic liquid electrolytes (LCILEs), a promising class of materials for next-generation lithium-ion batteries. Here, we investigate how varying diluent concentrations modulate lithium-anion interactions, ion dynamics, and transport properties in LCILEs. Using molecular dynamics (MD) simulations combined with density functional theory (DFT) calculations, we show that incorporating 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) as a diluent minimally perturbs the solvation structure while effectively weakening Li+-anion interactions and promoting ionic dissociation. Adjusting the lithium salt-to-ionic liquid (IL) ratio alters the coordination environment of bis(fluorosulfonyl)imide anions (FSI-). It reduces the presence of pyrrolidinium cations in the lithium solvation shell. Beyond solvation effects, we further demonstrate that introducing lithium hexafluorophosphate (LiPF6) enhances ionic conductivity and increases the lithium-ion diffusion coefficient. By systematically exploring the impacts of diluent concentration and ionic additives, our theoretical framework offers molecular-level insights into how electrolyte composition influences lithium-ion mobility and interfacial stability, key factors in designing high-performance electrolytes for next-generation energy storage systems.

2025-09-30T15:00:00Z Lim, Minhong Chang, Hongjun Kim, Gunyoung Seo, Jiyeon Kim, Beomjun Choe, Seungho Lee, Hochun Moon, Janghyuk Lee, Hongkyung https://scholar.dgist.ac.kr/handle/20.500.11750/58553 2025-07-25T02:46:43Z 2025-05-31T15:00:00Z

Title: Interfacial impacts of diluent-mediated anion conformational changes in locally concentrated ionic liquid electrolytes Author(s): Lim, Minhong; Chang, Hongjun; Kim, Gunyoung; Seo, Jiyeon; Kim, Beomjun; Choe, Seungho; Lee, Hochun; Moon, Janghyuk; Lee, Hongkyung Abstract: Dilution methods employing weaker-solvating solvents as diluents have shown promise in reducing the viscosity of liquid electrolytes without disrupting the coordination between Li⁺ and anions. However, diluents alter the FSI− coordination conformation in locally concentrated ionic liquid electrolytes (LCILEs) by occupying the interstitial space between the Li+−FSI− complex and Pyr13+. The Li+−FSI− bond exhibits various energy states depending on the anion coordination conformation. By regulating the dilution extent, the HOMO level can be reduced, enabling higher voltage tolerance with fewer side reactions. Given that reinforcing the Li+−FSI− binding can contribute to reducing the HOMO level, TTE in-between Pyr13+ and FSI− possibly changes the anion conformation from bidentate to ambidentate coordination. Furthermore, moderate dilution promoting bidentate coordination facilitates the formation of a LiF-rich solid-electrolyte interphase (SEI). Herein, we present an optimally diluted CILE (LCILE-T1) that demonstrates superior cycle stability in a pouch-type full cell operating at 4.7 V, achieving over 240 cycles. © 2025

2025-05-31T15:00:00Z Choe, Seungho https://scholar.dgist.ac.kr/handle/20.500.11750/57446 2025-07-25T02:45:21Z 2024-09-30T15:00:00Z

Title: Insights into Translocation of Arginine-Rich Cell-Penetrating Peptides across a Model Membrane Author(s): Choe, Seungho Abstract: It is well-known that membrane deformation and water pores contribute to the spontaneous translocation of arginine-rich cell-penetrating peptides (CPPs). We confirm this through the observation of the spontaneous translocation of single R9 (nona-arginine) and Tat (48-60) peptides across a model membrane using the weighted ensemble (WE) method within all-atom molecular dynamics (MD) simulations. Furthermore, we demonstrate that membrane deformation and the presence of a water pore reduce the effective charge of the CPP and the bending rigidity of the model membrane during translocation. We find that R9 disturbs the model membrane more than Tat (48-60), leading to more efficient translocation of R9 across the model membrane. © 2024 American Chemical Society.

2024-09-30T15:00:00Z Ji, Seunghyun Abbas, Hafiz Ghulam Kim, Seo Young Lee, Hyo Cheol Lee, Kyunghoon Li, Shi Choe, Seungho Ahn, Hyungju Ringe, Stefan Yang, Jiwoong https://scholar.dgist.ac.kr/handle/20.500.11750/57215 2025-07-25T03:37:53Z 2024-12-31T15:00:00Z

Title: Nucleation-Controlled Doping of II–VI Semiconductor Nanocrystals Mediated by Magic-Sized Clusters Author(s): Ji, Seunghyun; Abbas, Hafiz Ghulam; Kim, Seo Young; Lee, Hyo Cheol; Lee, Kyunghoon; Li, Shi; Choe, Seungho; Ahn, Hyungju; Ringe, Stefan; Yang, Jiwoong Abstract: Doping quantum-confined semiconductor nanocrystals offers an effective way to tailor their unique properties. However, the inherent challenges of nanoscale doping processes, such as the low probability of successful doping, have hindered their practical applications. Nucleation-controlled doping has emerged as a potential solution, but a comprehensive mechanistic understanding of this process is lacking. Herein, the nucleation-controlled doping process facilitated by magic-sized cluster intermediates is elucidated. This approach enables the synthesis of 2D ZnSe quantum nanoribbons with two distinct doping sites. Remarkably, the identity of the dopants plays a critical role in determining the chemical pathways of nucleation-controlled doping. Substitutional doping of magic-sized clusters with Mn2+ ions leads to successful substitutional doping of the final 2D nanocrystals. Conversely, Co2+ ions, initially occupying substitutional positions in the magic-sized cluster intermediates, relocate to alternative sites, such as interstitial sites, in the final nanocrystals. First-principle calculations of dopant formation energies support these experimental findings, demonstrating the thermodynamic favorability of specific dopant site preferences. Moreover, a consistent tendency is observed in CdSe nanocrystals, suggesting that the proposed doping mechanism is generally applicable to II–VI semiconductors. This study will advance the controlled synthesis of various doped semiconductor nanocrystals using nucleation-controlled doping processes. © 2024 The Author(s). Small Science published by Wiley-VCH GmbH.

2024-12-31T15:00:00Z