https://scholar.dgist.ac.kr/handle/20.500.11750/211 2026-10-10T18:15:11Z https://scholar.dgist.ac.kr/handle/20.500.11750/60942 Title: Li2x Al1+x P1-x Cl8: A Halide Lithium-Ion Conductor Family Derived from the AlPCl8Framework Author(s): Seo, Hyeonjin; Shin, Seungyong; Manjon-Sanz, Alicia; Hong, Seung-Tae Abstract: Halide solid electrolytes are promising candidates for high-voltage all-solid-state batteries due to their high anodic stability. Here, we report the synthesis and characterization of lithium-containing halide solid electrolytes, Li2x Al1+x P1-x Cl8, based on the recently identified orthorhombic Pbcm structure of AlPCl8. Among the nominal compositions characterized by PXRD (x = 0.15, 0.2, 0.333, and 0.5), the x = 0.15 and 0.20 phases retain the AlPCl8-derived framework as single-phase products. The materials were prepared via stoichiometric mechanochemical synthesis followed by low-temperature annealing. Structural analysis using joint Rietveld refinements of X-ray and neutron diffraction data confirmed distorted tetrahedral interstitial lithium sites that interconnect AlCl4 and (P/Al)Cl4 polyhedra. Bond-valence site energy calculations reveal crystallographically accessible Li+ migration pathways with low local migration barriers of similar to 0.3 eV. The x = 0.20 composition exhibits an ionic conductivity of 6.3 & times; 10-7 S cm-1 at room temperature, with a negligible electronic conductivity of 1.9 & times; 10-10 S cm-1 and an apparent activation energy of similar to 1.6 eV. Despite the modest ionic transport, linear sweep voltammetry indicates a high oxidation onset at similar to 7.8 V vs In/In-Li, demonstrating high anodic stability among halide electrolytes. The large discrepancy between the calculated local barriers and the experimentally measured activation energy suggests that macroscopic Li+ transport is governed by factors beyond the intrinsic local hopping barrier. These results establish the AlPCl8-derived framework as a useful structural platform for exploring chloride-based Li+ conductors with accessible migration pathways and high oxidative stability. 2026-08-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60875 Title: Kinetic origin and mitigation of sudden capacity fade in silicon-based lithium-ion batteries Author(s): Jeon, Jiyun; Kang, Junsik; Park, Dae-woon; Lim, Hyun Hee; Kang, Ayeon; Lee, Hyungjin; Hong, Seung-Tae; Lee, Hochun Abstract: Silicon (Si)-based full cells maintain stable cycling at elevated temperatures yet exhibit a sudden capacity fade at room temperature. This temperature-dependent behavior is specific to Si-based full cells and cannot be explained by conventional graphite-based degradation models. This study identifies the origin of the fade mechanism as a Si-intrinsic, kinetics-driven degradation process and proposes a corresponding mitigation strategy. Electrochemical and post-mortem analyses show that intrinsically sluggish Si kinetics at 25 degrees C induce a large overpotential that drives lithium plating and accelerates surface degradation. Guided by this understanding, a formation strategy is introduced to suppress lithium plating onset, which is shown to prevent sudden capacity fade and improve capacity retention from 38% to 85% in NCM/Si cells and from 55% to 93% in NCM/Si-Gr cells. By elucidating the kinetic origin of the sudden capacity fade and establishing formation engineering as an effective and scalable control strategy, this work addresses key challenges in the practical implementation of high-energy Si-based lithium-ion batteries. (c) 2026 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights are reserved, including those for text and data mining, AI training, and similar technologies. 2026-05-31T15:00:00Z 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