Publications by authors named "Byeongyong Lee"

The ligand engineering for single-atom catalysts (SACs) is considered a cutting-edge strategy to tailor their electrocatalytic activity. However, the fundamental reasons underlying the reaction mechanism and the contemplation for which the actual active site for the catalytic reaction depends on the pyrrolic and pyridinic N ligand structure remain to be fully understood. Herein, we first reveal the relationship between the oxygen reduction reaction (ORR) activity and the N ligand structure for the manganese (Mn) single atomic site by the precisely regulated pyrrolic and pyridinic N coordination environment.

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Lithium-ion batteries (LIBs) stand as a compelling solution to energy source transition in various applications such as the vehicle industry due to their energy and power density. However, the impact of mechanical factors on them remains understudied. Of particular interest is the effect of vibration, an inherent characteristic of vehicles, on battery performance.

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Soft energy storage devices, such as supercapacitors, are an essential component for powering integrated soft microsystems. However, conventional supercapacitors are mainly manufactured using hard/brittle materials that easily crack and eventually delaminate from the current collector by mechanical deformation. Therefore, to realize all-soft supercapacitors, the electrodes should be soft, stretchable, and highly conductive without compromising the electrochemical performance.

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To achieve excellent photoelectrochemical water-splitting activity, photoanode materials with high light absorption and good charge-separation efficiency are essential. One effective strategy for the production of materials satisfying these requirements is to adjust their band structure and corresponding bandgap energy by introducing oxygen vacancies. A simple chemical reduction method that can systematically generate oxygen vacancies in barium stannate (BaSnO (BSO)) crystal is introduced, which thus allows for precise control of the bandgap energy.

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It is crucial for leaping forward renewable energy technology to develop highly active oxygen evolution reaction (OER) catalysts with fast OER kinetics, and the novel design of high-performance catalysts may come down to unveiling the origin of high catalytic behavior. Herein, a new class of heterogeneous OER electrocatalyst (metallic Co nanoparticles anchored on yttrium ruthenate pyrochlore oxide) is provided for securing fast OER kinetics. In situ X-ray absorption spectroscopy (in situ XAS) reveals that fast OER kinetics can be achieved by the harmonious catalytic synergy of a pyrochlore oxide support to Co nanoparticles.

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This comprehensive Review focuses on the key challenges and recent progress regarding sodium-metal anodes employed in sodium-metal batteries (SMBs). The metal anode is the essential component of emerging energy storage systems such as sodium sulfur and sodium selenium, which are discussed as example full-cell applications. We begin with a description of the differences in the chemical and physical properties of Na metal versus the oft-studied Li metal, and a corresponding discussion regarding the number of ways in which Na does not follow Li-inherited paradigms in its electrochemical behavior.

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Nanostructured graphene electrodes generally have a low density, which can limit the volumetric performance for energy storage devices. The liquid-phase mild reduction process of graphene oxide sheets is combined with the continuous aerosol densification process to produce high-density graphene agglomerates in the form of microspheres. The produced graphene assembly shows the cabbage-like morphology with a high density of 0.

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Polydopamine, a functional coating material, is redox active as cathode materials for both Li- and Na-ion batteries or hybrid capacitors. Here, a polydopamine coating onto 3D graphene framework is introduced through a simple hydrothermal process, during which graphene oxide serves not only as an oxidant for assisting the polymerization of dopamine, but also as a template for the conformal growth of polydopamine. High-density films are fabricated by compressing the polydopamine-coated graphene aerogels, which can be directly used as free-standing and flexible cathodes in both Li- and Na-cells.

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The effective implantation of conductive and charge storage materials into flexible frames has been strongly demanded for the development of flexible supercapacitors. Here, we introduce metallic cellulose paper-based supercapacitor electrodes with excellent energy storage performance by minimizing the contact resistance between neighboring metal and/or metal oxide nanoparticles using an assembly approach, called ligand-mediated layer-by-layer assembly. This approach can convert the insulating paper to the highly porous metallic paper with large surface areas that can function as current collectors and nanoparticle reservoirs for supercapacitor electrodes.

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Crumpled graphene is known to have a strong aggregation-resistive property due to its unique 3D morphology, providing a promising solution to prevent the restacking issue of graphene based electrode materials. Here, we demonstrate the utilization of redox-active oxygen functional groups on the partially reduced crumpled graphene oxide (r-CGO) for electrochemical energy storage applications. To effectively utilize the surface redox reactions of the functional groups, hierarchical networks of electrodes including r-CGO and functionalized few-walled carbon nanotubes (f-FWNTs) are assembled via a vacuum-filtration process, resulting in a 3D porous structure.

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One hundred and eleven male patients with alcohol dependence and 123 nonalcoholic healthy men were tested for the genetic polymorphisms of alcohol dehydrogenase 2 (ADH2), aldehyde dehydrogenase 2 (ALDH2), serotonin transporter (5-HTT) and dopamine transporter (DAT1). There were significant differences in genotype frequencies of ADH2 C992G and A13543G SNPs between alcoholic patients with family history of alcohol dependence (familial) and alcoholic patients without family history (non-familial). Genotype and allele frequencies of ALDH2 G1951A SNP in familial or non-familial alcoholic patients differ from normal controls.

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