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Jeonghun Kim

Bio: Jeonghun Kim is an academic researcher from Yonsei University. The author has contributed to research in topics: Mesoporous material & Materials science. The author has an hindex of 50, co-authored 177 publications receiving 8967 citations. Previous affiliations of Jeonghun Kim include Qingdao University of Science and Technology & University of Queensland.


Papers
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Journal ArticleDOI
TL;DR: Insightful insights gathered in the process of studying TMS are provided, and valuable guidelines for engineering other kinds of nanomaterial catalysts for energy conversion and storage technologies are described.
Abstract: Heterogenous electrocatalysts based on transition metal sulfides (TMS) are being actively explored in renewable energy research because nanostructured forms support high intrinsic activities for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, it is described how researchers are working to improve the performance of TMS-based materials by manipulating their internal and external nanoarchitectures. A general introduction to the water-splitting reaction is initially provided to explain the most important parameters in accessing the catalytic performance of nanomaterials catalysts. Later, the general synthetic methods used to prepare TMS-based materials are explained in order to delve into the various strategies being used to achieve higher electrocatalytic performance in the HER. Complementary strategies can be used to increase the OER performance of TMS, resulting in bifunctional water-splitting electrocatalysts for both the HER and the OER. Finally, the current challenges and future opportunities of TMS materials in the context of water splitting are summarized. The aim herein is to provide insights gathered in the process of studying TMS, and describe valuable guidelines for engineering other kinds of nanomaterial catalysts for energy conversion and storage technologies.

899 citations

Journal ArticleDOI
TL;DR: This Account focuses mostly on carbons derived from two types of MOFs, namely, zeolite imidazolate framework-8 (ZIF-8 and ZIF-67), and shows the uniqueness of these carbons for achieving high performance by control of the chemical reactions/conditions as well proper utilization in asymmetric/symmetric supercapacitor configurations.
Abstract: ConspectusThe future advances of supercapacitors depend on the development of novel carbon materials with optimized porous structures, high surface area, high conductivity, and high electrochemical stability. Traditionally, nanoporous carbons (NPCs) have been prepared by a variety of methods, such as templated synthesis, carbonization of polymer precursors, physical and chemical activation, etc. Inorganic solid materials such as mesoporous silica and zeolites have been successfully utilized as templates to prepare NPCs. However, the hard-templating methods typically involve several synthetic steps, such as preparation of the original templates, formation of carbon frameworks, and removal of the original templates. Therefore, these methods are not favorable for large-scale production.Metal–organic frameworks (MOFs) with high surface areas and large pore volumes have been studied over the years, and recently, enormous efforts have been made to utilize MOFs for electrochemical applications. However, their lo...

629 citations

Journal ArticleDOI
09 Jan 2020-Chem
TL;DR: In this article, metal-organic framework (MOF)-derived carbon materials (CMs) have drawn great interest in many fields of application, such as energy storage and conversion, environmental remediation, and catalysis.

476 citations

Journal ArticleDOI
TL;DR: In this article, highly conductive poly(3,4-ethylenedioxythiophene): poly(4-styrenesulfonate) (PEDOT:PSS)/graphene composites fabricated by in situ polymerization and their applications in a thermoelectric device and a platinum (Pt)-free dye-sensitized solar cell (DSSC) as energy harvesting systems.
Abstract: We report for the first time highly conductive poly(3,4-ethylenedioxythiophene): poly(4-styrenesulfonate) (PEDOT:PSS)/graphene composites fabricated by in situ polymerization and their applications in a thermoelectric device and a platinum (Pt)-free dye-sensitized solar cell (DSSC) as energy harvesting systems. Graphene was dispersed in a solution of poly(4-styrenesulfonate) (PSS) and polymerization was directly carried out by addition of 3,4-ethylenedioxythiophene (EDOT) monomer to the dispersion. The content of the graphene was varied and optimized to give the highest electrical conductivity. The composite solution was ready to use without any reduction process because reduced graphene oxide was used. The fabricated film had a conductivity of 637 S·cm−1, corresponding to an enhancement of 41%, after the introduction of 3 wt.% graphene without any further complicated reduction processes of graphene being required. The highly conductive composite films were employed in an organic thermoelectric device, and the device showed a power factor of 45.7 μW·m−1K−2 which is 93% higher than a device based on pristine PEDOT:PSS. In addition, the highly conductive composite films were used in Pt-free DSSCs, showing an energy conversion efficiency of 5.4%, which is 21% higher than that of a DSSC based on PEDOT:PSS.

357 citations

Journal ArticleDOI
TL;DR: The applications of these hollow structures as electrode materials for lithium-ion batteries, hybrid supercapacitors, and electrocatalysis are presented and an outlook on the emergent challenges and future developments in terms of their controllable fabrications and electrochemical applications is further discussed.
Abstract: Hollow materials derived from metal-organic frameworks (MOFs), by virtue of their controllable configuration, composition, porosity, and specific surface area, have shown fascinating physicochemical properties and widespread applications, especially in electrochemical energy storage and conversion. Here, the recent advances in the controllable synthesis are discussed, mainly focusing on the conversion mechanisms from MOFs to hollow-structured materials. The synthetic strategies of MOF-derived hollow-structured materials are broadly sorted into two categories: the controllable synthesis of hollow MOFs and subsequent pyrolysis into functional materials, and the controllable conversion of solid MOFs with predesigned composition and morphology into hollow structures. Based on the formation processes of hollow MOFs and the conversion processes of solid MOFs, the synthetic strategies are further conceptually grouped into six categories: template-mediated assembly, stepped dissolution-regrowth, selective chemical etching, interfacial ion exchange, heterogeneous contraction, and self-catalytic pyrolysis. By analyzing and discussing 14 types of reaction processes in detail, a systematic mechanism of conversion from MOFs to hollow-structured materials is exhibited. Afterward, the applications of these hollow structures as electrode materials for lithium-ion batteries, hybrid supercapacitors, and electrocatalysis are presented. Finally, an outlook on the emergent challenges and future developments in terms of their controllable fabrications and electrochemical applications is further discussed.

350 citations


Cited by
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TL;DR: Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency as mentioned in this paper, and many DSC research groups have been established around the world.
Abstract: Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency. DSC research groups have been established around the worl ...

8,707 citations

Journal ArticleDOI
TL;DR: The supercapacitor, the electric double-layer capacitor, and the so-called "reduction and oxidation, redox" technology are all being developed.
Abstract: 슈퍼캐패시터(supercapacitor)는 배터리와 함께 많은 양의 전기에너지를 저장 및 공급하 는 중요한 에너지 저장 장치이다. 특히 슈퍼캐 패시터는 고출력이 가능하고 크기와 형태가 조절가능하여 전자기기 부터 자동차 까지 그 사용분야가 매우 넓다 [1-3]. 최근에 웨어러블 (wearable) 디바이스와 플렉서블(flexible) 전 자기기의 발달과 함께 구부릴 수 있고, 당길 수 있는(stretchable) 슈퍼캐패시터의 개발 또한 활발히 진행되고 있다 [4-8]. 슈퍼캐패시터의 작동원리에 따라 전기이중층 캐패시터(electric double-layer capacitor, EDLC)와 의사캐패시터 (pseudocapacitor)로 나뉜다. EDLC는 전하분 리현상을 이용하기 때문에 넓은 표면적을 갖 는 활성탄(activated carbon)과 같은 전극 재료 를 사용하며 의사캐패시터는 전극 재료의 산 화·환원반응(reduction and oxidation, redox) 을 이용하므로 redox반응을 잘 일으키면서 넓 은 표면적을 갖는 전도성 고분자와 금속산화 물 등의 전극 재료를 사용하게된다 [9]. 슈퍼캐 패시터의 전극 재료로서 높은 에너지 저장능 력 및 성능을 갖으려면, 일반적으로 높은 표면 적을 갖도록 해야하며, 슈퍼캐패시터의 성능 은 전극 활물질의 모폴로지(morphology), 기 공크기분포(pore size distribution), 전기전도 도(electrical conductivity), 표면 특성, 열 특성 등의 다양한 성질에 의해 결정되며, 이를 최적 화 했을 때 높은 성능의 슈퍼캐패시터의 제조 가 가능하다 [1]. 일반적으로 다공성 구조의 카 본 및 금속산화물을 만들기 위해서 그 재료의 전구체를 계면활성제(surfactant)를 이용하여 모폴러지 및 다공성을 조절하였다. 계면활성 제의 사용은 다양한 모양과 구조의 활물질제 조를 가능하게 하였지만, 많은 양의 계면활성 제의 사용은 시약의 가격, 후처리, 환경적인 측 면에서 단점을 가진다. 금속유기구조체(metal-organic frameworks, MOFs)는 금속이온과 유기물 연결체(organic linker)로 만들어진 조성물로서, 합성 시 이러한 추가적인 계면활성제의 사용없이 매우 높은 표 면적을 갖는 금속유기 조성물을 만들 수 있다 (그림 1). 이러한 MOF는 사용되는 금속이온, 유 기연결체, 결정구조 등에 따라 MOF-N, HKUSTN, ZIF-N 등 (N: number)으로 구분되어 명명된 다 (그림 1(b)) [10, 11] . 또한, 사용하는 금속이 온과 유기물 연결체의 종류에 따라 다공성 특 성을 조절할 수 있고, 이들의 열처리를 통해서 다공성 카본체 및 금속산화물의 제조가 가능하 다 [12]. 더욱이, MOF는 기존의 다양한 재료에 적용이 가능하여 다양한 에너지저장 재료로 만 들어 질 수 있으며, 나노기술 및 다양한 접근 방 법을 통해 나노구조체 및 조성물의 합성이 가 능하다 [13]. 이러한 장점으로 인해 최근 많은 종류의 MOF 물질들이 슈퍼캐패시터 및 2차전 지의 에너지 저장시스템(energy storage systems, ESSs) 에 응용되고 있다 (그림 2). MOF 중 이미다졸(imidazole) 유도체를 유기연결체로

2,635 citations

Journal ArticleDOI
TL;DR: Switches, and Actuators Masahiro Irie,*, Tuyoshi Fukaminato,‡ Kenji Matsuda, and Seiya Kobatake.
Abstract: Switches, and Actuators Masahiro Irie,*,† Tuyoshi Fukaminato,‡ Kenji Matsuda, and Seiya Kobatake †Research Center for Smart Molecules, Rikkyo University, Nishi-Ikebukuro 3-34-1, Toshima-ku, Tokyo 171-8501, Japan ‡Research Institute for Electronic Science, Hokkaido University, N20, W10, Kita-ku, Sapporo 001-0020, Japan Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan Department of Applied Chemistry, Graduate School of Engineering, Osaka City University, Sugimoto 3-3-138, Sumiyoshi-ku, Osaka 558-8585, Japan

1,884 citations