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Insight into the Electrode Mechanism in Lithium-Sulfur Batteries with Ordered Microporous Carbon Confined Sulfur as the Cathode

Authors

  • Zhen Li,

    1. Key Laboratory for Advanced Battery Materials and System (MOE), School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
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  • Lixia Yuan,

    Corresponding author
    1. Key Laboratory for Advanced Battery Materials and System (MOE), School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
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  • Ziqi Yi,

    1. Key Laboratory for Advanced Battery Materials and System (MOE), School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
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  • Yongming Sun,

    1. Key Laboratory for Advanced Battery Materials and System (MOE), School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
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  • Yang Liu,

    1. Key Laboratory for Advanced Battery Materials and System (MOE), School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
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  • Yan Jiang,

    1. Key Laboratory for Advanced Battery Materials and System (MOE), School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
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  • Yue Shen,

    1. Key Laboratory for Advanced Battery Materials and System (MOE), School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
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  • Ying Xin,

    1. Shandong Provincial Key Laboratory of Fluorine Chemistry and Chemical Materials, School of Chemistry and Chemical Engineering, University of Jinan, Jinan, Shandong, China
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  • Zhaoliang Zhang,

    1. Shandong Provincial Key Laboratory of Fluorine Chemistry and Chemical Materials, School of Chemistry and Chemical Engineering, University of Jinan, Jinan, Shandong, China
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  • Yunhui Huang

    Corresponding author
    1. Key Laboratory for Advanced Battery Materials and System (MOE), School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan, Hubei, China
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Abstract

In lithium-sulfur batteries, small S2–4 molecules show very different electrochemical responses from the traditional S8 material. Their exact lithiation/delitiation mechanism is not clear and how to select proper electrolytes for the S2–4 cathodes is also ambiguous. Here, S2–4 and S8/S2–4 composites with highly ordered microporous carbon as a confining matrix are fabricated and the electrode mechanism of the S2–4 cathode is investigated by comparing the electrochemical performances of the S2–4 and S2–4/S8 electrodes in various electrolytes combined with theoretical calculation. Experimental results show that the electrolyte and microstructure of carbon matrix play important roles in the electrochemical performance. If the micropores of carbon are small enough to prevent the penetration of the solvent molecules, the lithiation/delithiation for S2–4 occurs as a solid-solid process. The irreversible chemically reactions between the polysulfudes and carbonates, and the dissolution of the polysulfides into the ethers can be effectively avoided due to the steric hindrance. The confined S2–4 show high adaptability to the electrolytes. The sulfur cathode based on this strategy exhibits excellent rate capability and cycling stability.

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