https://scholar.dgist.ac.kr/handle/20.500.11750/836 2026-04-04T16:56:31Z 2026-04-04T16:56:31Z Kang, Dongyoon Jeong, Minseok Kim, Suhwan Song, Myunggeun Dzakpasu, Cyril Bubu Kim, Sun Hyu Lim, Jaejin Eom, Sewon Jung, Seonghyeon Jang, Jieun Jo, Seungyun Jeon, Heeji Lee, Hyobin Choi, Seungyeop Jo, Taejin Lee, Hochun Ryu, Du Yeol Kim, Jeonghun Lee, Yong Min https://scholar.dgist.ac.kr/handle/20.500.11750/59095 2025-10-17T01:40:13Z 2025-09-30T15:00:00Z

Title: A Tailored Adhesive-Conductive Interlayer for Interface Stabilization of Large-Scale Lithium Metal Powder Electrodes for High-Energy-Density Batteries Author(s): Kang, Dongyoon; Jeong, Minseok; Kim, Suhwan; Song, Myunggeun; Dzakpasu, Cyril Bubu; Kim, Sun Hyu; Lim, Jaejin; Eom, Sewon; Jung, Seonghyeon; Jang, Jieun; Jo, Seungyun; Jeon, Heeji; Lee, Hyobin; Choi, Seungyeop; Jo, Taejin; Lee, Hochun; Ryu, Du Yeol; Kim, Jeonghun; Lee, Yong Min Abstract: To address the limitations in thickness and width of lithium (Li) metal electrodes produced through traditional extrusion and pressing processes, a slurry-based coating method utilizing Li metal powder (LMP) is investigated, enabling the fabrication of ultra-thin and broad-width Li electrodes by simply tuning the coating conditions. Despite these advancements, LMP electrodes face critical challenges, including delamination of the LMP composite layer from the Cu current collector (CC) due to electrolyte infiltration at the interface and degradation of interfacial connectivity during charging/discharging cycles. To mitigate these issues, an adhesive-conductive polymer (AC-polymer) interlayer composed of poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(styrene sulfonate-co-acrylic acid) (P(SS-co-AA) is introduced between the LMP composite layer and the Cu CC to improve interfacial stability. The incorporation of the AC-polymer interlayer significantly reduced the Li stripping overpotential from 89.8 to 35.8mV (a 60% decrease) and enhanced cycling stability, achieving 91% capacity retention at a 4mA cm−2 discharging rate after 150 cycles, even in a carbonate-based electrolyte. The successful fabrication of a 300mm-wide and 20µm-thick slurry-coated AC-LMP electrode represents a notable advancement in the development of Li metal batteries.

2025-09-30T15:00:00Z Kang, Junsik Lee, Hochun https://scholar.dgist.ac.kr/handle/20.500.11750/58959 2025-10-17T02:10:13Z 2025-09-30T15:00:00Z

Title: Enhancing Salt Diffusivity of Battery Electrolytes: Insights from Dynamic Ion Correlation Analysis Author(s): Kang, Junsik; Lee, Hochun Abstract: Playing a critical role in electrolyte ion transport, ion correlations influence concentration polarization and ultimately contribute to the rate performance of Li-ion batteries. This study demonstrates that introducing monoglyme co-solvent into a carbonate-based electrolyte enhances salt diffusivity (Dsalt) by 30%, effectively mitigating concentration polarization and improving the rate capability of a LiCoO2 symmetric cell by 70% at 4C operation. Dynamic ion correlation analysis reveals that the improvement in Dsalt is driven by increased positive self-correlations of cations and anions, which represent enhanced random movement of ions, facilitated by reduced viscosity and smaller solvation shell sizes. Conversely, introducing diglyme co-solvent reduces Dsalt and deteriorates the rate capability. Although diglyme also improves self-correlations through reduced viscosity, its stronger Li-ion solvation increases cation–cation anti-correlation, resulting in an unfavorable balance between the correlation terms that suppresses overall salt diffusivity. These findings underscore the significant influence of microscopic ion correlations on macroscopic transport properties, a crucial aspect in optimizing battery performance. © 2025 Wiley-VCH GmbH.

2025-09-30T15:00:00Z Kang, Seokbum Lee, Hochun https://scholar.dgist.ac.kr/handle/20.500.11750/58689 2025-07-25T02:47:58Z 2025-07-31T15:00:00Z

Title: Recent Progress of the Crystalline Organic Electrolytes for Solid-State Battery Applications Author(s): Kang, Seokbum; Lee, Hochun Abstract: Crystalline organic electrolytes (COEs) have recently emerged as promising alternatives to conventional solid-state electrolytes, including oxide, sulfide, and polymeric electrolytes. This interest arises from the limitations of traditional solid-state electrolytes, which often suffer from inadequate ionic conductivity, poor electrochemical stability, and difficulty in establishing intimate contact with cathode particles. In this review, COEs are introduced with a focus on their classification, unique characteristics, and case studies highlighting their application in solid-state batteries. COEs are fundamentally composed of alkali metal salts and organic crystalline solvents. Based on the type of solvent, they are classified into three categories: organic ionic plastic crystal electrolytes (OIPCs), non-ionic plastic crystal electrolytes (NIPCs), and non-plastic crystal organic electrolytes (NOPCs). COEs offer several advantageous properties, including high ionic conductivity, low-to-negligible flammability, and excellent compatibility with electrodes achieved through melt-casting processes. These features position COEs as a transformative solution for advancing solid-state battery technologies, enabling the development of safe, high-performance, and energy-dense devices for electrified applications. © 2025, Korean Electrochemical Society. All rights reserved.

2025-07-31T15:00:00Z Kang, Junsik Lee, Hochun https://scholar.dgist.ac.kr/handle/20.500.11750/58575 2025-08-12T09:10:25Z 2025-03-31T15:00:00Z

Title: Deciphering Potential Shifts in Highly Concentrated LiTFSI Aqueous Electrolytes Author(s): Kang, Junsik; Lee, Hochun Abstract: Uncertainties persist in determining the electrochemical stability window of concentrated electrolytes due to the Nernst shift (ΔEN) and the liquid junction potential (ΔEj). This study investigates potential shifts in LiTFSI aqueous solutions across a broad concentration range. By characterizing Li-ion transference numbers and thermodynamic factors, we identify concentration- and activity coefficient-dependent ΔEN and ΔEj in LiTFSI electrolytes, observed in concentration cells with LiFePO4 electrodes. Our findings reveal that a sharp increase in the mean ionic activity coefficient at high salt concentrations drives a substantial upward shift in the Li-ion (de)-intercalation potential, which contributes 65% of the total potential shift between 1 and 5 M solutions. In contrast, ΔEj has a less significant impact. Correcting for ΔEj then allowed an accurate analysis of how LiTFSI concentration affects the redox characteristics of the Fe(CN)63–/4– couple. These findings help deepen our understanding of electrochemical dynamics in highly concentrated solutions. © 2025 American Chemical Society

2025-03-31T15:00:00Z