Sangwook Kim

4.8 V and All‐Climate (−60 to 55°C) All‐Solid‐State Batteries Enabled by Dual‐Phase Symbiotic Halide Solid Electrolytes

Zihan Xu, Ao Zeng, Kesheng Gao, Zhigang Zhang et autres

ABSTRACT Overcoming the intrinsic trade‐off between high‐voltage compatibility, thermal stability, and low‐temperature ionic conductivity in halide solid electrolytes remains a critical challenge for advancing all‐solid‐state lithium batteries (ASSLBs). Here, we propose a chemical symbiosis strategy to design a dual‐phase halide electrolyte integrating …

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4.8 V and All‐Climate (−60 to 55°C) All‐Solid‐State Batteries Enabled by Dual‐Phase Symbiotic Halide Solid Electrolytes

Zihan Xu, Ao Zeng, Kesheng Gao, Zhigang Zhang et autres

ABSTRACT Overcoming the intrinsic trade‐off between high‐voltage compatibility, thermal stability, and low‐temperature ionic conductivity in halide solid electrolytes remains a critical challenge for advancing all‐solid‐state lithium batteries (ASSLBs). Here, we propose a chemical symbiosis strategy to design a dual‐phase halide electrolyte integrating …

cn, jp (code pays fourni par la source)

Nondestructive visualization of a 1 μm-sized single grain inside a 0.3 mm-thick polycrystalline barium titanate

Norihiro Oshime, Kenji Ohwada, Mingyang Shao, K. Sakaguchi et autres

Understanding how poling treatments enhance the functional properties of ferroelectric ceramics requires nondestructive visualization of strain, defects, and domain structures within individual grains in ceramics that are processed into a form suitable for mounting, without destroying them. Here, we establish a high-energy …

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Structural heterogeneity and diffuse structural evolution in ground (Bi 0.5 Na 0.5 )TiO 3 –BaTiO 3 ceramics revealed by synchrotron radiation X-ray diffraction

Kanato Mizoguchi, K. Sakaguchi, Sangwook Kim, Shinya Tsukada et autres

The temperature-dependent evolution of the structural components in bulk and ground 87.5%(Bi 0.5 Na 0.5 )TiO 3 –12.5%BaTiO 3 (BNT–BT) ceramics was investigated using synchrotron radiation X-ray diffraction. Both the bulk and ground samples exhibited the coexistence of cubic ( Pm 3 …

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Quenching-induced enhancement of ferroelectricity via electron density redistribution and Bi off-centering

Genki Izu, Sangwook Kim, Motoki Aruga, Hyunwook Nam et autres

The structural origin of quenching-induced enhancement in the ferroelectricity of 0.95(0.33BaTiO 3 –0.67BiFeO 3 )–0.05Bi(Mg 0.5 Ti 0.5 )O 3 ceramics was investigated using synchrotron radiation X-ray diffraction and electron density analysis. Rietveld refinement revealed that both as-sintered and quenched ceramics possessed …

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Effect of grain orientation on depolarization and phase transition temperatures of 0.85(Bi0.5Na0.5)TiO3-0.15BaTiO3 ceramics

Ichiro Fujii, Kosuke Kawachi, Sota Saito, Shintaro Ueno et autres

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Effect of lotus-type porous cu on reliability of ag-sintered joints during thermal cycling

Minsu Kim, Hiroaki Tatsumi, Sangwook Kim, Ji-Hyun Kim et autres

This study examines the effect of unidirectional porous copper (lotus Cu) on the reliability of Ag-sintered interfaces between Si and Cu during thermal cycling. In high-performance wide-bandgap semiconductor power modules, the large coefficient of thermal expansion (CTE) mismatch generates significant thermomechanical stresses, …

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Ferroelectricity restoration via thermally driven recovery of surface damage layers in BiFeO 3 ‐based lead‐free ceramics

Sangwook Kim, Hyunwook Nam, Hae In Choi

Abstract The effect of mechanically induced surface damage layers on the crystal structure and ferroelectric properties was systematically investigated in lead‐free 0.99(0.67BiFeO 3 −0.33BaTiO 3 )−0.01BiMnO 3 ceramics. The surface damage layer formed by mechanical polishing was identified through diffraction peak broadening, …

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Enhancing thermal reliability of ceramic substrates using lotus-type porous copper

Sang-Gyu Choi, Sangwook Kim, Keun-Soo Kim, Soong‐Keun Hyun

A novel design employing lotus-type porous copper was proposed and evaluated to improve the thermal reliability of alumina (Al 2 O 3 )-based direct bonded copper (DBC) substrates. Finite element method (FEM) simulations were conducted to analyze the thermal stress and plastic …

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Optimization of Direct Bonding Process for Lotus-Type Porous Copper to Alumina Substrates

Sang-Gyu Choi, Sangwook Kim, J.H. Lee, Keun-Soo Kim et autres

The effects of processing conditions and holding time on the direct bonding (DBC) of lotus-type porous copper to alumina substrates were systematically investigated. The evolution of copper morphology and the resulting shear strength were evaluated under varying pressures (0.3–0.6 Torr) and bonding …

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Joining of lotus-type porous copper to alumina substrate by direct bonded copper technique

Sang-Gyu Choi, Sangwook Kim, J.H. Lee, Keun-Soo Kim et autres

This study investigates the Direct Bonded Copper (DBC) process using lotus copper, a unidirectional porous material, for direct bonding to alumina ceramic substrates. Lotus copper is fabricated via a continuous casting process in a hydrogen-nitrogen atmosphere. When using the conventional DBC method, …

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Predictive Modeling of Shear Strength for Lotus-Type Porous Copper Bonded to Alumina

Sang-Gyu Choi, Sangwook Kim, J.H. Lee, Keun-Soo Kim et autres

This study investigates the shear strength of lotus-type unidirectional porous copper bonded to alumina substrates using the Direct Bonded Copper (DBC) process. Porous copper specimens with various porosities (38.7–50.9%) and pore sizes (150–800 μm) were fabricated and joined to alumina discs. Shear …

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