Publications by authors named "Yuwon Park"

Mild-acid Zn-MnO batteries have been considered a promising alternative to Li-ion batteries for large scale energy storage systems because of their high safety. There have been remarkable improvements in the electrochemical performance of Zn-MnO batteries, although the reaction mechanism of the MnO cathode is not fully understood and still remains controversial. Herein, the reversible dissolution/deposition (Mn/Mn) mechanism of the MnO cathode through a 2e reaction is directly evidenced using solution-based analyses, including electron spin resonance spectroscopy and the designed electrochemical experiments.

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We report a facile two-step method to synthesize nanostructured P2-Na2/3MnO2via ligand exchange and intercalation of sodium ions into ultrathin manganese oxide nanoplates. Sodium storage performance of the synthesized material shows a high capacity (170 mA h g-1) and an excellent rate performance.

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Electrode materials exploiting multielectron-transfer processes are essential components for large-scale energy storage systems. Organic-based electrode materials undergoing distinct molecular redox transformations can intrinsically circumvent the structural instability issue of conventional inorganic-based host materials associated with lattice volume expansion and pulverization. Yet, the fundamental mechanistic understanding of metal-organic coordination polymers toward the reversible electrochemical processes is still lacking.

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P2-type manganese-based oxide materials have received attention as promising cathode materials for sodium ion batteries because of their low cost and high capacity, but their reaction and failure mechanisms are not yet fully understood. In this study, the reaction and failure mechanisms of β-Na[MnLi]O (x = 0.02, 0.

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Ordered meso- or macro-porous carbons (OMCs) were applied as anodes in Na ion battery (NIB) systems. Three different block copolymers (BCPs) enabled us to control the pore sizes (6, 33, and 60 nm) while maintaining the same 2-D hexagonal structure. To exclude other effects, the factors including precursors, particle sizes, and degrees of graphitization were controlled.

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The π-π interaction-dependent vapour pressure of phenanthrenequinone can be used to synthesize a phenanthrenequinone-confined ordered mesoporous carbon. Intimate contact between the insulating phenanthrenequinone and the conductive carbon framework improves the electrical conductivity. This enables a more complete redox reaction take place.

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SnSe alloy is examined for the first time as an anode for Na-ion batteries, and shows excellent electrochemical performance including a high reversible capacity of 707 mA h g(-1) and stable cycle performance over 50 cycles. Upon sodiation, SnSe is changed into amorphous NaxSn nanodomains dispersed in crystalline Na2Se, and SnSe is reversibly restored after desodiation.

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Lithium-ion batteries (LIBs) are considered to be key energy storage systems needed to secure reliable, sustainable, and clean energy sources. Redox-active organic compounds have been proposed as interesting candidates for electrode materials for the next-generation LIBs because of their flexible molecular design, recyclability, and low production cost. Despite wide interest, a molecular-level understanding of the electrochemical lithiations/delithiations of those materials remains rudimentary.

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An amorphous red phosphorus/carbon composite is obtained through a facile and simple ball milling process, and its electrochemical performance as an anode material for Na ion batteries is evaluated. The composite shows excellent electrochemical performance including a high specific capacity of 1890 mA h g(-1), negligible capacity fading over 30 cycles, an ideal redox potential (0.4 V vs.

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Disodium terephthalate and its various derivatives are synthesized via simple acid-base chemistry for anode materials in Na ion batteries. They show excellent electrochemical performance, including little capacity fading over 90 cycles, ideal redox potential, and excellent rate performance, making them promising candidates for Na ion batteries.

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