https://scholar.dgist.ac.kr/handle/20.500.11750/57519 2026-10-29T00:53:09Z https://scholar.dgist.ac.kr/handle/20.500.11750/61008 Title: Preserving reversible transition metal redox centers in the O3-type layered oxide cathodes for high-energy sodium-ion batteries Author(s): Oh, Gwangeon; Shin, Heesung; Kansara, Shivam; Park, Jaehyun; Kang, Hyokyeong; Lee, Soo-Yeon; Kim, Un-Hyuck; Park, Soohyung; Lee, Seon Hwa; Park, Yoon-Cheol; Nam, Sang-Cheol; Hong, Jeong-Jin; Hwang, Jang-Yeon Abstract: The O3-type Na[Ni1/3Fe1/3Mn1/3]O2 (O3-NFM) cathode has attracted considerable attention for sodium-ion batteries (SIBs) owing to its reversible Na+ storage and low cost. However, the practical application of the O3-NFM cathode is limited by insufficient energy density. In this study, through the regulation of crystal and electronic structures, we design the high-energy density O3-Na0.94Ca0.03[(Ni1/3Fe1/3Mn1/3)0.99Al0.01]O2 (O3-CNFMA) cathode. In theory, the incorporation of Ca2+ and Al3+ suppresses transition metal (TM) migration into Na layer and irreversible oxygen reaction while promoting TM-centered redox behavior. Ca2+ in the Na layer act as a pillar, mitigating lattice strain during deep Na extraction. Al strengthens TM-O bonding and widens Na slab spacing, enhancing Na+ kinetics. Furthermore, partial Al3+ substitution disrupts continuous TM-O-TM superexchange pathways and weakens long-range magnetic connectivity, which increases the energetic barrier for cation rearrangement and restrains irreversible Fe migration under deep charging operation to 4.2 V (vs. Na/ Na+). In the voltage window of 2.0-4.2 V, the O3-CNFMA cathode delivers 175.5 mAh g-1 with 99.1% Coulombic efficiency, excellent cycling stability, and power capability without noticeable microcracking. Moreover, it exhibits strong water resistance and long-term cycling stability in a hard carbon-based pouch-type full cell. 2026-09-30T15:00:00Z 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