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409 results on '"Kang, Yong‐Mook"'

24. Regulating the "core-shell" microstructure of hard carbon through sodium hydroxide activation for achieving high-capacity SIBs anode.

Author

Wang, Haihua, Niu, Huizhu, Shu, Kewei, Sun, Liyu, Wang, Yu, Du, Yifan, Han, Yun, Yang, Cunguo, and Kang, Yong-Mook

Subjects
CARBON-based materials, HARD materials, POROUS materials, COAL tar, POROSITY
Abstract

• Coal-derived hard carbon material used as SIBs anode. • Preparation SIBs anode through NaOH activated and surface coating. • Closed pores enable efficient storage of sodium in the plateau region. • Carbon layer coating reduces disorder and improves rate and cycling performance. • The specific capacity of CNA1200 is 335.2 mAh g−1 at 20 mA g−1 with ICE=51.53 %. Pore structure engineering has been acknowledged as suitable approach to creating active sites and enhancing ion transport capabilities of hard carbon anodes. However, conventional porous carbon materials exhibit high BET and surface defects. Additionally, the sodium storage mechanism predominantly occurs in the slope region. This contradicts practical application requirements because the capacity of the plateau region is crucial for determining the actual capacity of batteries. In our work, we prepared a novel "core-shell" carbon framework (CNA1200). Introducing closed pores and carboxyl groups into coal-based carbon materials to enhance its sodium storage performance. The closed pore structure dominates in the "core" structure, which is attributed to the timely removal of sodium hydroxide (NaOH) to prevent further formation of active carbon structure. The presence of closed pores is beneficial for increasing sodium ion storage in the low-voltage plateau region. And the "shell" structure originates from coal tar pitch, it not only uniformly connects hard carbon particles together to improve cycling stability, but is also rich in carboxyl groups to enhance the reversible sodium storage performance in slope region. CNA1200 has excellent electrochemical performance, it exhibits a specific capacity of 335.2 mAh g−1 at a current density of 20 mA g−1 with ICE = 51.53 %. In addition, CNA1200 has outstanding cycling stability with a capacity retention of 91.8 % even when cycling over 200 times. When CNA1200 is used as anode paired with Na 3 V 2 (PO 4) 3 cathode, it demonstrates a capacity of 109.54 mAh g−1 at 0.1 C and capacity retention of 94.64 % at 0.5 C. This work provides valuable methods for regulating the structure of sodium-ion battery (SIBs) anode and enhances the potential for commercialization. [Display omitted] [ABSTRACT FROM AUTHOR]

Published
2025
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31. Revealing the Potential and Challenges of High‐Entropy Layered Cathodes for Sodium‐Based Energy Storage.

Author

Gao, Hong, Li, Jiayi, Zhang, Fan, Li, Congcong, Xiao, Jun, Nie, Xinming, Zhang, Guilai, Xiao, Yang, Zhang, Dingyi, Guo, Xin, Wang, Yong, Kang, Yong‐Mook, Wang, Guoxiu, and Liu, Hao

Subjects
ENERGY storage, CLEAN energy, JAHN-Teller effect, STRUCTURAL stability, HIGH voltages, CHEMICAL kinetics, CATHODES
Abstract

Sodium‐ion batteries (SIBs) reflect a strategic move for scalable and sustainable energy storage. The focus on high‐entropy (HE) cathode materials, particularly layered oxides, has ignited scientific interest due to the unique characteristics and effects to tackle their shortcomings, such as inferior structural stability, sluggish reaction kinetics, severe Jahn‐Teller effects induced lattice distortion, and poor oxygen reversibility at high voltage. This review focuses on high‐entropy oxide materials, highlighting their fundamentals, design principles, and application in layered oxide cathodes for SIBs. It delves into the growth mechanism, composition‐properties correlations, and the functional roles of high‐entropy design in enhancing the performance of layered oxide cathodes. Furthermore, it furnishes a comprehensive survey of recent advancements and persisting challenges within the domain of layered high‐entropy cathode materials, as well as offers insights into potential future research directions in line with the current state of knowledge. [ABSTRACT FROM AUTHOR]

Published
2024
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44. Unraveling the Significance of Li+/e−/O2 Phase Boundaries with a 3D‐Patterned Cu Electrode for Li–O2 Batteries.

Author

Hyun, Gayea, Park, Mihui, Bae, Gwangmin, Chung, Jong‐woan, Ham, Youngjin, Cho, Seonyong, Jung, Seungwon, Kim, Suhwan, Lee, Yong Min, Kang, Yong‐Mook, and Jeon, Seokwoo

Subjects
LITHIUM-air batteries, COPPER, ELECTRODES, CHEMICAL kinetics, STRUCTURAL engineers
Abstract

The reaction kinetics at a triple‐phase boundary (TPB) involving Li+, e−, and O2 dominate their electrochemical performances in Li–O2 batteries. Early studies on catalytic activities at Li+/e−/O2 interfaces have enabled great progress in energy efficiency; however, localized TPBs within the cathode hamper innovations in battery performance toward commercialization. Here, the effects of homogenized TPBs on the reaction kinetics in air cathodes with structurally designed pore networks in terms of pore size, interconnectivity, and orderliness are explored. The diffusion fluxes of reactants are visualized by modeling, and the simulated map reveals evenly distributed reaction areas within the periodic open structure. The 3D air cathode provides highly active, homogeneous TPBs over a real electrode scale, thus simultaneously achieving large discharge capacity, unprecedented energy efficiency, and long cyclability via mechanical/electrochemical stress relaxation. Homogeneous TPBs by cathode structural engineering provide a new strategy for improving the reaction kinetics beyond controlling the intrinsic properties of the materials. [ABSTRACT FROM AUTHOR]

Published
2023
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