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Your search keyword '"Yoon, Chong S."' showing total 348 results
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348 results on '"Yoon, Chong S."'

13. Long‐lasting, reinforced electrical networking in a high‐loading Li2S cathode for high‐performance lithium–sulfur batteries.

Author

Kim, Hun, Min, Kyeong‐Jun, Bang, Sangin, Hwang, Jang‐Yeon, Kim, Jung Ho, Yoon, Chong S., and Sun, Yang‐Kook

Abstract

Realizing a lithium sulfide (Li2S) cathode with both high energy density and a long lifespan requires an innovative cathode design that maximizes electrochemical performance and resists electrode deterioration. Herein, a high‐loading Li2S‐based cathode with micrometric Li2S particles composed of two‐dimensional graphene (Gr) and one‐dimensional carbon nanotubes (CNTs) in a compact geometry is developed, and the role of CNTs in stable cycling of high‐capacity Li–S batteries is emphasized. In a dimensionally combined carbon matrix, CNTs embedded within the Gr sheets create robust and sustainable electron diffusion pathways while suppressing the passivation of the active carbon surface. As a unique point, during the first charging process, the proposed cathode is fully activated through the direct conversion of Li2S into S8 without inducing lithium polysulfide formation. The direct conversion of Li2S into S8 in the composite cathode is ubiquitously investigated using the combined study of in situ Raman spectroscopy, in situ optical microscopy, and cryogenic transmission electron microscopy. The composite cathode demonstrates unprecedented electrochemical properties even with a high Li2S loading of 10 mg cm–2; in particular, the practical and safe Li–S full cell coupled with a graphite anode shows ultra‐long‐term cycling stability over 800 cycles. [ABSTRACT FROM AUTHOR]

Published
2023
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29. Synthesis of [L1.sub.0] [(FePt).sub.100-X]-[Au.sub.X] nanoparticle monolayer on polyimide film

Author

Kim, Jung H., Kim, Ryeon K., An, Hyeun H., and Yoon, Chong S.

Subjects
Nanoparticles -- Magnetic properties, Ferromagnetic materials -- Properties, Dielectric films -- Magnetic properties, Thin films -- Magnetic properties, Business, Electronics, Electronics and electrical industries
Abstract

A monolayer of [L1.sub.0] FePt nanoparticles was fabricated on a polymer film by introducing a Au seed layer prior to the Fe-Pt deposition on the polyimide film. The particle size distribution was tightened from 5.1 [+ or -] 1.8 nm to 3.8 [+ or -] 1.1 nm by introducing the Au seeds to induce a preferential nucleation of the deposited metal on the preexisting Au particles. Deposition and annealing was repeated so that well-separated hard magnetic nanoparticles with several nanometers in diameter were achieved in a monolayer configuration. The method can be easily extended to a larger area as well as to other alloy systems to create a monolayer of nanoisland structures on a polymer film. Index Terms--Ferromagnetic materials, magnetic recording, polyimide films, quantum dots.

Published
2009

34. Cation ordered Ni-rich layered cathode for ultra-long battery life

Author

Kim, Un-Hyuck, primary, Park, Geon-Tae, additional, Conlin, Patrick, additional, Ashburn, Nickolas, additional, Cho, Kyeongjae, additional, Yu, Young-Sang, additional, Shapiro, David A., additional, Maglia, Filippo, additional, Kim, Sung-Jin, additional, Lamp, Peter, additional, Yoon, Chong S., additional, and Sun, Yang-Kook, additional

Published
2021
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