https://scholar.dgist.ac.kr/handle/20.500.11750/57520 2026-04-22T01:42:20Z https://scholar.dgist.ac.kr/handle/20.500.11750/60213 Title: Localized defective zone formation driven by selective Li+ extraction defines the high-voltage threshold of LiNi0.6Co0.2Mn0.2O2 Author(s): Lee, Gawon; Go, Min Chang; Wang, Hanqun; Choi, Chang-Min; Kim, Hee-Soo; Lee, Jemok; Kim, Un-Hyuck; Yoon, Chong Seung Abstract: A structural investigation of an archetypal mid-Ni layered cathode, LiNi0.6Co0.2Mn0.2O2, charged to voltages between 4.3 V and 4.7 V, is performed to assess its structural stability at deep charge levels and determine its suitability for high-voltage cycling. Besides interparticle cracks, cracks within primary particles start to form above 4.5 V. The microstructure of primary particles is characterized by alternating bands of defect-free regions and areas containing numerous structural faults, likely caused by uneven Li ion extraction. Intraparticle cracks often originate at the boundary of these banded regions. Additionally, an unreported intermediate phase appears within the defective band. Electrochemical data confirm that 4.5 V (210 mAh g-1 at 0.1 C) is probably the limit at which LiNi0.6Co0.2Mn0.2O2 can be cycled without major capacity loss. This study reveals that the structural degradation of LiNi0.6Co0.2Mn0.2O2 during deep charging is highly localized due to the selective extraction of Li ions. Therefore, reducing the Li concentration difference at the cathode surface would prevent the formation of localized defective zones and enhance the cycling stability of LiNi0.6Co0.2Mn0.2O2 above 4.5 V. 2026-01-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59885 Title: Redefining polymer binders: enabling ion transport and interfacial stability in sulfide-based all-solid-state lithium batteries Author(s): Hong, Seung-Bo; Lee, Young-Jun; Kim, Hun; Go, Min Chang; Kim, Un-Hyuck; Sun, Yang-Kook; Kim, Dong-Won Abstract: Research on sulfide-based all-solid-state lithium batteries (ASSLBs) has predominantly focused on primary components such as active materials, solid electrolytes, and conductive carbons. In contrast, polymer binders have received relatively little attention, despite their critical influence on cell performance. The lack of systematic understanding and rational design strategies for binder materials hinders their effective contribution to the practical development of ASSLBs. While previous studies have primarily emphasized the binders’ mechanical integrity and processability, their potential contribution to ionic conductivity and interfacial stability remains largely unexplored. Departing from this traditional focus, this review highlights the essential role of polymer binders in enhancing interfacial adhesion and maintaining continuous Li+ ion conductive pathways within electrodes and solid electrolyte sheets. Binder design should aim to integrate mechanical robustness with ionic functionality to promote uninterrupted ion transport. From this perspective, polymer binders are redefined as essential design elements that not only provide mechanical cohesion but also compensate for ion transport limitations and stabilize internal interfaces. Their strategic integration at the film level is anticipated to be a decisive factor in advancing ASSLBs technologies. 2025-11-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/58245 Title: All-Solid-State Batteries with Anodeless Electrodes: Research Trend and Future Perspective Author(s): Jeon, Sang-Jin; Kim, Un-Hyuck; Kwag, Sang Hoon; Min, Jin-Wook; Kim, Dong-Won; Kim, Hansu; Lee, Yun-Jung; Jung, Yun-Chae Abstract: All-solid-state batteries (ASSBs) are promising "beyond lithium-ion batteries" candidates owing to their high energy density and safety. Anodeless electrodes are critical components for enabling these attributes, offering a fundamentally distinct mechanism compared to conventional anode systems. This unique mechanism of anodeless electrodes has garnered significant scientific interest and has prompted extensive research. Based on recent advancements, this perspective provides comprehensive insights into anodeless electrode materials in ASSBs and outlines prospective research directions to address the remaining challenges and further ASSB performance optimization. 2025-06-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/57204 Title: Relaxation of the Jahn–Teller stress effect in the P3-type K0.5MnO2 cathode by copper and magnesium co-substitution for high-performance K-ion batteries Author(s): Oh, Yunjae; Lee, Hoseok; Oh, Gwangeon; Ryu, Seongje; Kim, Un-Hyuck; Jung, Hun-Gi; Kim, Jongsoon; Hwang, Jang-Yeon Abstract: The Mn-based P3-type layered oxide (K0.5MnO2) is a promising cathode material for K-ion batteries (KIBs) because of its low cost, high specific capacity, and simple synthesis. However, it suffers from severe capacity loss and sluggish K+ diffusion kinetics, which are mainly attributed to multiple phase transitions and the Jahn–Teller distortion of Mn3+. To address these challenges, herein, the Mg and Cu co-substitution strategy is proposed to synthesize the P3-type K0.5Mn0.8Mg0.1Cu0.1O2 (P3-KMMCO) as a cathode for KIBs. The presence of divalent Mg2+ and Cu2+ in the crystal structure of P3-KMMCO play the critical functions in regulating the Jahn–Teller-active Mn3+, thereby suppressing the complex phase transitions and improving the K+ diffusion kinetics during charging and discharging. As a result, the P3-KMMCO cathode demonstrates the high reversible capacity, outstanding cycling stability and power capability. A combination study of synchrotron-based X-ray analysis and first-principles calculations is used to validate the enhanced electrochemical K+ storage properties of the P3-KMMCO cathode. © 2024 2025-01-31T15:00:00Z