Outstanding Catalytic Effects of 1T'-MoTe2 Quantum Dots@3D Graphene in Shuttle-Free Li-S Batteries

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

doi:10.1021/acsnano.1c03011

Outstanding Catalytic Effects of 1T'-MoTe₂ Quantum Dots@3D Graphene in Shuttle-Free Li-S Batteries

ACS Nano. 2021 Aug 24;15(8):13279-13288. doi: 10.1021/acsnano.1c03011. Epub 2021 Aug 5.

Authors

Bo Yu¹, Aijian Huang^{1

2}, Katam Srinivas¹, Xiaojuan Zhang¹, Fei Ma¹, Xinqiang Wang¹, Dongjiang Chen¹, Bin Wang¹, Wanli Zhang¹, Zegao Wang³, Jiarui He⁴, Yuanfu Chen^{1

5}

Affiliations

¹ State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China.
² Department of Chemistry, Tsinghua University, Beijing 100084, China.
³ College of Materials Science and Engineering, Sichuan University, Chengdu 610065, China.
⁴ Department of Mechanical Engineering and Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712, United States.
⁵ School of Science, Tibet University, Lhasa 850000, China.

PMID: 34351124
DOI: 10.1021/acsnano.1c03011

Abstract

It is still challenging to develop sulfur electrodes for Li-S batteries with high electrical conductivity and fast kinetics, as well as efficient suppression of the shuttling effect of lithium polysulfides. To address such issues, herein, polar MoTe₂ with different phases (2H, 1T, and 1T') were deeply investigated by density functional theory calculations, suggesting that the 1T'-MoTe₂ displays concentrated density of states (DOS) near the Fermi level with high conductivity. By optimization of the synthesis, 1T'-MoTe₂ quantum dots decorated three-dimensional graphene (MTQ@3DG) was prepared to overcome these issues, and it accomplished exceptional performance in Li-S batteries. Owing to the chemisorption and high catalytic effect of 1T'-MoTe₂ quantum dots, MTQ@3DG/S exhibits highly reversible discharge capacity of 1310.1 mAh g^-1 at 0.2 C with 0.026% capacity fade rate per cycle over 600 cycles. The adsorption calculation demonstrates that the conversion of Li₂S₂ to Li₂S is the rate-limiting step where the Gibbs free energies are 1.07 eV for graphene and 0.97 eV for 1T'-MoTe₂, revealing the importance of 1T'-MoTe₂. Furthermore, in situ Raman spectroscopy investigation proved the suppression of the shuttle effect of LiPSs in MTQ@3DG/S cells during the cycle.

Keywords: Li−S batteries; catalyst design; graphene; metallic 1T′-MoTe2; quantum dots.