https://scholar.dgist.ac.kr/handle/20.500.11750/12112 2026-04-22T04:37:01Z https://scholar.dgist.ac.kr/handle/20.500.11750/46227 Title: Electrode-level strategies enabling kinetics-controlled metallic Li confinement by the heterogeneity of interfacial activity and porosity Author(s): Shin, Hong Rim; Kim, Siwon; Park, Junho; Kim, Jung Ho; Park, Min -Sik; Lee, Jong-Won Abstract: Three-dimensional (3D) host architectures have emerged as promising strategies for resolving the critical issues of Li metal anodes, namely, severe volume changes and growth of Li dendrites during battery cycling. However, preferential Li plating on top of the host architecture often causes early cell failure. Herein, we demonstrate that the controlled heterogeneity of interfacial activity and the porous structure at the electrode level enables confined Li metal storage in host architectures consisting of metal-organic framework (MOF)-derived carbon. 3D electrochemical simulations show that carbon activity (lithiophilicity) and interparticle porosity play critical roles in controlling the competing kinetics of charge transfer and Li+ transport, thereby regulating the Li-plating behavior. The enhanced lithiophilicity at the electrode bottom, combined with the increased interparticle porosity at the top, is predicted to promote the preferential nucleation of Li and subsequent upward growth from the bottom. Based on the proposed design principles, high-capacity and long-cycling host architectures based on MOF-derived carbon are constructed via two-step electrophoretic deposition (EPD): densely populated Ag-incorporated carbon at the bottom in combination with sparsely populated Ag-free carbon at the top. The heterogeneous host architecture fabricated by EPD spatially confines a large amount of Li metal (6 mAh cm–2) without significant volume changes and exhibits a long cycle lifetime of over 900 cycles. This study provides an effective strategy for designing advanced Li metal anodes by controlling the competing reaction kinetics in 3D host architectures. © 2023 Elsevier B.V. 2023-01-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/17491 Title: Mechanistic Insight into Wettability Enhancement of Lithium-Ion Batteries Using a Ceramic-Coated Layer Author(s): Jeon, Dong Hyup; Song, Jung-Hoon; Yun, Jonghyeok; Lee, Jong-Won Abstract: The crucial issue of wettability in high-energy-density lithium-ion batteries (LIBs) has not been comprehensively addressed to date. To overcome the challenge, state-of-the-art LIBs employing a ceramic-coated separator improves the safety- and wettability-related aspects of LIBs. Here, we present a mechanistic study of the effects of a ceramic-coated layer (CCL) on electrode wettability and report the optimal position of the CCL in LIBs. The electrolyte wetting was investigated using the multiphase lattice Boltzmann method and electrochemical impedance spectroscopy for capturing the electrolyte-transport dynamics in porous electrodes and impedance spectra in pouch-type LIBs, respectively. Results indicate that the CCL caused the velocity vector to transport the electrolyte further, resulting in an increase in the wetting rate. Moreover, the location of the CCL considerably affected the wettability of the LIBs. This study provides mechanical insight into the design and fabrication of high-performance LIBs by incorporating CCLs. © 2022 American Chemical Society. 2022-12-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/17435 Title: Physically driven enhancement of the stability of Bi2O3-based ionic conductors via grain boundary engineering Author(s): Jeong, Incheol; Jeong, Seung Jin; Yun, Byung-Hyun; Lee, Jong-Won; Lee, Chan-Woo; Jung, WooChul; Lee, Kang Taek Abstract: Fast oxygen-ion conductors for use as electrolyte materials have been sought for energy conversion and storage. Bi2O3-based ionic conductors that exhibit the highest known oxygen-ion conductivities have received attention for use in next-generation solid electrolytes. However, at intermediate temperatures below ~600 °C, their conductivities degrade rapidly owing to a cubic-to-rhombohedral phase transformation. Here, we demonstrate that physical manipulation of the grain structure can be used to preserve the superior ionic conductivity of Bi2O3. To investigate the effects of microstructural control on stability, epitaxial and nanopolycrystalline model films of Er0.25Bi0.75O1.5 were fabricated by pulsed laser deposition. Interestingly, in situ impedance and ex situ XRD analyses showed that the grain boundary-free epitaxial film significantly improved the stability of the cubic phase, while severe degradation was observed in the conductivity of its polycrystalline counterpart. Consistently, the cation interdiffusion coefficient measured by the Boltzmann–Matano method was much lower for the epitaxial thin film compared to the polycrystalline thin film. Furthermore, first-principles calculations revealed that the presence of grain boundaries triggered the structural resemblance between cubic and rhombohedral phases, as evidenced by radial distribution functions. Additionally, phase transition energetics predicted that the thermodynamic stability of the cubic phase with respect to the rhombohedral counterpart is reduced near grain boundaries. Thus, these findings provide novel insights into the development of highly durable superionic conductors via microstructural engineering. © 2022, The Author(s). 2022-11-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/17363 Title: Biphasic solid electrolytes with homogeneous Li-ion transport pathway enabled by metal–organic frameworks Author(s): Won, E.-S.; Shin, H.R.; Jeong, W.; Yun, J.; Lee, J.-W. Abstract: Solid-state lithium batteries (SSLBs) based on non-flammable inorganic solid electrolytes have been proposed as promising technical solutions to resolve safety issues caused by flammable organic liquid electrolytes of current Li-ion batteries. Biphasic solid electrolytes (BSEs) comprising Li+-conducting oxides and polymers have garnered significant interest for SSLBs because of their mechanical robustness and high Li+ conductivity. However, the non-uniform distribution of oxide particles and polymer species in BSEs may cause inhomogeneous Li+ conduction, thereby resulting in poor interfacial stability with electrodes during repeated charge–discharge cycles. Herein, we report a Li7La3Zr2O12-based BSE with homogeneous Li+ transport pathways achieved by a metal–organic framework (MOF) layer. To regulate and homogenize the Li+ flux across the interface between the BSE and electrode, a free-standing BSE is integrated with the MOF layer. The MOF-integrated BSE forms smooth and uniform interfaces with nanoporous channels in contact with the electrodes, effectively enhancing the interfacial solid–solid contact and facilitating homogeneous Li+ transport. An SSLB with the MOF-BSE membrane shows enhanced cycling stability and rate-capability compared to the battery with bare BSE. This study demonstrates that the proposed electrolyte design provides an effective approach for improving the conducting properties and interfacial stability of BSEs for high-performance and long-cycling SSLBs. © 2022 Elsevier Ltd 2022-05-31T15:00:00Z