https://scholar.dgist.ac.kr/handle/20.500.11750/213 2026-08-03T15:11:02Z https://scholar.dgist.ac.kr/handle/20.500.11750/60515 Title: Crystallographic Stability and No Evidence of Higher-Order Saddle Points in the HfFe6Ge6-type Kagome Metal ScCo6Ge6 Author(s): Park, Jaemun; Rhee, Taeseong; Cho, Beopgil; Jeong, Yunseong; Hong, Seung-Tae; Kim, Heung-Sik; Park, Keeseong Abstract: While kagome RT6X6 (R = Li, Mg, Zr, and rare-earth metals; T = 3d transition metals; X = Ge/Sn) compounds are widely studied, Co-based RCo6X6 phases remain largely limited to structural reports, with few systematic studies of their physical properties. Here we report Sn-flux-grown single-crystalline ScCo6Ge6 and its structural and physical characterization. Single-crystal X-ray diffraction confirms that ScCo6Ge6 adopts the HfFe6Ge6-type structure rather than the vacancy-driven Y0.5Co3Ge3-type variant. Across the RCo6Ge6 series, structural preference correlates with the Shannon ionic radius of R (8-fold coordination), placing ScCo6Ge6 within the stability range of the HfFe6Ge6-type framework. Magnetization exhibits weak temperature dependence consistent with Pauli-like paramagnetism. The resistivity is well described by a Bloch-Gruneisen form with a Debye temperature exceeding 230 K, consistent with phonon-dominated scattering. Electrical transport also shows a conventional linear Hall response and negligible magnetoresistance, indicative of simple metallic behavior. Electronic structure calculations identify a Ge-derived quadratic saddle point similar to 0.35 eV below E F, with no evidence of higher-order saddle points near the Fermi level. These results highlight that crystallographic stability and physical properties in RCo6Ge6 are governed not only by the Co kagome lattice but also sensitively by the Ge sublattice. 2026-03-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60513 Title: Lithiophilic Current Collector Without Interfacial Penalty in Zero-Excess Lithium Metal Batteries Author(s): Seo, Jiyeon; Lee, Sangseob; Jeon, Seojin; Lim, Minhong; Koo, Hyegang; Hong, Seung-Tae; Jang, Woosun; Soon, Aloysius; Lee, Hongkyung Abstract: Highly reversible lithium (Li) plating/stripping in zero-excess Li metal batteries (ZE-LMBs) demands lithiophilic current collectors to suppress Li dendrite formation and Li pulverization. Although Li-alloyable metals have been recognized as lithiophilic substrates, their structural and interfacial stability over cycling are still poorly understood. Here, we present a bimetallic lithiophilic current collector through sequential coatings of platinum (Pt) and silver (Ag). Experimental and computational studies reveal that Ag facilitates uniform Li nucleation and seamless solid electrolyte interphase (SEI) formation owing to the low Li diffusion barrier and strong anion adsorption, whereas Pt maintains lithiophilicity and structural integrity. Leveraging this complementarity, the Ag-outer/Pt-inner bilayer (Ag/Pt@Cu) achieves superior cycling stability through location-specific functional decoupling: the outer Ag layer ensures uniform Li deposition and robust SEI formation, whereas the inner Pt layer supports long-term lithiophilicity, thereby outperforming the reversed configuration (Pt/Ag@Cu). Given that the structural robustness of lithiophilic coatings is essential for enhancing the cycling performance of ZE-LMBs, this study provides a versatile design framework for multi-component, multi-layer architectures, enabling the rational engineering of structurally resilient, lithiophilic current collectors. 2026-05-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60473 Title: A Proton-Intercalation Pathway Realizes Long-Life Manganese-Ion Hybrid Batteries With Layered KV3O8 Author(s): Lee, Sangki; Lee, Hyungjin; Pyun, Jangwook; Lee, Hyeonjun; Roh, Ki-min; Lee, Kang Taek; Hong, Seung-Tae; Jin, Xiaoyan; Jeong, Incheol; Hwang, Seong-Ju; Chae, Munseok S. Abstract: Rechargeable aqueous manganese-based batteries offer a low-cost, high-safety, and promising solution to meet the growing demand for large-scale energy storage systems. However, since aqueous manganese-ion batteries (AMIBs) are still in the early stages of development, discovering high-performance cathode materials is critical for enabling future commercialization. In this study, we introduce monoclinic KV3O8 as a highly stable and unprecedented cathode material for AMIBs. KV3O8 has a layered structure with an interlayer spacing of approximately 7.63 & Aring; (d(001)), which facilitates the reversible intercalation and deintercalation of cations. This structural feature ensures excellent long-term cycling stability (88.0% capacity retention after 3600 cycles) and outstanding rate capability. By integrating diffusion path and barrier calculations with X-ray photoelectron spectroscopy, ex situ X-ray absorption spectroscopy, ex situ X-ray diffraction, Fourier-transform infrared spectroscopy, and Raman spectroscopy, we identify both Mn2+ ions and protons as active charge carriers. Furthermore, the formation of a Mn(OH)(2) layer on the cathode surface during discharge suggests that protons predominantly govern the charge storage mechanism. This study provides critical insights into the design of advanced manganese ion cathode materials and represents a significant step toward the practical realization of AMIBs. 2026-04-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60001 Title: Proton-dominant charge storage in layered H2V3O8 for Mn2+/H+ hybrid aqueous batteries Author(s): Pyun, Jangwook; lee, Hyeonjun; Lee, Yeon-U; Lee, Sangki; Hong, Seung-Tae; Aurbach, Doron; Chae, Munseok S. Abstract: Aqueous rechargeable batteries (ARBs) are compelling for grid‑scale storage owing to their cost effectiveness, promising safety features, and sustainability. Within this landscape, Mn‑based batteries offer a deeper redox potential (−1.19 V vs. SHE), high theoretical energy density, abundance, and low toxicity. However, the large hydrated radius and strong electrostatic interactions of Mn²⁺ in water severely hinder bulk intercalation and, thus, reversible capacity. Here we demonstrate a Mn²⁺/H⁺ hybrid chemistry using layered H₂V₃O₈ as the cathode host. These electrodes may deliver high specific capacity > 320 mAh g⁻¹ at 0.2 A g⁻¹ and may retain around 70 % of their initial capacity after 3500 cycles. Comprehensive spectroscopic and structural analyses revealed that Mn²⁺ mainly forms surface by‑products and functions as a secondary charge carrier, whereas protons dominate the charge compensation. This dual‑ion mechanism underpins the high capacity, fast kinetics, and durable cycling. Mn metal//H₂V₃O₈ full cells can operate at 1.23 V, benefiting from the large electrodes’ potential gap, and exhibits robust electrochemical performance. Our results clarify the interplay between Mn²⁺ and H⁺ in aqueous media and position H₂V₃O₈ as a promising cathode platform for next‑generation, safe, and sustainable energy storage devices. 2025-12-31T15:00:00Z