In Situ Construction of Mo2 C Quantum Dots-Decorated CNT Networks as a Multifunctional Electrocatalyst for Advanced Lithium-Sulfur Batteries

Bo Yu; Aijian Huang; Dongjiang Chen; Katam Srinivas; Xiaojuan Zhang; Xinqiang Wang; Bin Wang; Fei Ma; Chunlin Liu; Wanli Zhang; Jiarui He; Zegao Wang; Yuanfu Chen

doi:10.1002/smll.202100460

In Situ Construction of Mo₂ C Quantum Dots-Decorated CNT Networks as a Multifunctional Electrocatalyst for Advanced Lithium-Sulfur Batteries

Small. 2021 Jun;17(23):e2100460. doi: 10.1002/smll.202100460. Epub 2021 Apr 23.

Authors

Bo Yu¹, Aijian Huang¹, Dongjiang Chen², Katam Srinivas¹, Xiaojuan Zhang¹, Xinqiang Wang¹, Bin Wang¹, Fei Ma¹, Chunlin Liu¹, Wanli Zhang¹, Jiarui He³, Zegao Wang⁴, Yuanfu Chen^{1

5}

Affiliations

¹ School of Electronic Science and Engineering, and State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China.
² School of Physics, University of Electronic Science and Technology of China, Chengdu, 611731, P. R. China.
³ Materials Science and Engineering Program & Texas Materials Institute, the University of Texas at Austin, Austin, TX, 78712, USA.
⁴ College of Materials Science and Engineering, Sichuan University, Chengdu, 610065, P. R. China.
⁵ School of Science, and Institute of Oxygen Supply, Tibet University, Lhasa, 850000, P. R. China.

PMID: 33891797
DOI: 10.1002/smll.202100460

Abstract

The slow redox kinetics during cycling process and the serious shuttle effect caused by the solubility of lithium polysulfides (LiPSs) dramatically hinder the practical application of Li-S batteries. Herein, a facile and scalable spray-drying strategy is presented to construct conductive polar Mo₂ C quantum dots-decorated carbon nanotube (CNT) networks (MCN) as an efficient absorbent and electrocatalyst for Li-S batteries. The results reveal that the MCN/S electrode exhibits a high specific capacity of 1303.3 mAh g^-1 at 0.2 C, and ultrastable cycling stability with decay of 0.019% per cycle even at 1 C. Theoretical simulation uncovers that Mo₂ C exhibits much stronger binding energies for S₈ and Li₂ S_n . The energy barrier for the conversion between Li₂ S₄ and Li₂ S₂ decreases from 1.02 to 0.72 eV when hybriding with Mo₂ C. Furthermore, in situ discharge/charge-dependent Raman spectroscopy shows that long-chain Li₂ S₈ configuration is generated via S₈ ring opening near the first plateaus at ≈2.36 V versus Li/Li⁺ and the S₆ ^2- configuration in CNT/S electrode is maintained below the potential of ≈2.30 V versus Li/Li⁺ , indicating that the shuttle of soluble LiPSs happens during the whole discharge process. This work provides deep insights into the polar nanoarchitecture design and scalable fabrication for advanced Li-S batteries.

Keywords: adsorption ability; high catalytic activity; in situ Raman spectroscopy; lithium-sulfur batteries; polar Mo 2C quantum dots.

Abstract

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