Block-Copolymer-Assisted One-Pot Synthesis of Ordered Mesoporous WO3−x/Carbon Nanocomposites as High-Rate-Performance Electrodes for Pseudocapacitors

Authors

  • Changshin Jo,

    1. Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Kyungbuk 790-784, Republic of Korea
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  • Jongkook Hwang,

    1. Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Kyungbuk 790-784, Republic of Korea
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  • Hannah Song,

    1. Energy System Major, School of Mechanical Engineering, Pusan National University, Busan 609-735, Republic of Korea
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  • Anh Ha Dao,

    1. Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Kyungbuk 790-784, Republic of Korea
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  • Yong-Tae Kim,

    1. Energy System Major, School of Mechanical Engineering, Pusan National University, Busan 609-735, Republic of Korea
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  • Sang Hyup Lee,

    1. Center for Water Resource Cycle Research, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea
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  • Seok Won Hong,

    1. Center for Water Resource Cycle Research, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea
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  • Songhun Yoon,

    Corresponding author
    1. Department of Integrative Engineering, Chung-Ang University, 221, Heukseok-Dong, Dongjak-Gu, Seoul, 156-756, Republic of Korea
    • Department of Integrative Engineering, Chung-Ang University, 221, Heukseok-Dong, Dongjak-Gu, Seoul, 156-756, Republic of Korea.
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  • Jinwoo Lee

    Corresponding author
    1. Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Kyungbuk 790-784, Republic of Korea
    • Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Kyungbuk 790-784, Republic of Korea
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Abstract

An ordered mesoporous tungsten-oxide/carbon (denoted as m-WO3−x-C-s) nanocomposite is synthesized using a simple one-pot method using polystyrene-block-poly(ethylene oxide) (PS-b-PEO) as a structure-directing agent. The hydrophilic PEO block interacts with the carbon and tungsten precursors (resol polymer and WCl6), and the PS block is converted to pores after heating at 700 °C under a nitrogen flow. The m-WO3−x-C-s nanocomposite has a high Brunauer–Emmett–Teller (BET) surface area and hexagonally ordered pores. Because of its mesoporous structure and high intrinsic density of tungsten oxide, this material exhibits a high average volumetric capacitance and gravimetric capacitance as a pseudocapacitor electrode. In comparison with reduced mesoporous tungsten oxide (denoted as m-WO3−x-h), which is synthesized by a tedious hard template approach and further reduction in a H2/N2 atmosphere, m-WO3−x-C-s shows a high capacitance and enhanced rate performance, as confirmed by cyclic voltammetry, galvanostatic charge/discharge measurements, and electrochemical impedance spectroscopy. The good performance of m-WO3−x-C-s is attributed to the high surface area arising from the mesoporous structure, the large interconnected mesopores, and the low internal resistance from the well-dispersed reduced tungsten oxide and amorphous carbon composite structure. Here, the amorphous carbon acts as an electrical pathway for effective pseudocapacitor behavior of WO3-x.

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