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Fast electrochemical kinetics and strong polysulfide adsorption by a highly oriented MoS₂ nanosheet@N-doped carbon interlayer for lithium–sulfur batteries

Author:
Wu, Jingyi, Li, Xiongwei, Zeng, Hongxia, Xue, Yang, Chen, Fangyan, Xue, Zhigang, Ye, Yunsheng, Xie, Xiaolin
Source:
Journal of materials chemistry A 2019 v.7 no.13 pp. 7897-7906
ISSN:
2050-7496
Subject:
active sites, adsorption, batteries, carbon, cathodes, electrochemistry, electrons, encapsulation, energy, lithium, molybdenum disulfide, nanocomposites, nanosheets, reaction kinetics, sulfur
Abstract:
The polysulfide shuttle effect and sluggish reaction kinetics can severely reduce the sulfur utilization and cycle stability of Li–S batteries, undermining their use in practical applications. Herein, we design a core–shell nanocomposite by encapsulating radially oriented MoS₂ nanosheets by porous nitrogen-doped carbon (MoS₂@NC) via an eco-friendly method. The highly oriented MoS₂ nanosheets in MoS₂@NC avoid aggregation of the active sites for polysulfide adsorption, and the desirable integration of the catalytic MoS₂ nanosheet core and a highly conductive carbon shell provides a constant flow of electrons to the captured polysulfides for improved polysulfide conversion kinetics. The combined benefits of high polysulfide inhibition and smooth electron and Li⁺ transfer by a thin layer of MoS₂@NC (3.3 μm thick) enable a simple sulfur–carbon black cathode with high reversible capacities, good rate performances (876 mA h g⁻¹ at 3C), an excellent cycle stability over 1500 cycles with a negligible 0.034% decay per cycle, and satisfactory areal capacities with increased sulfur loading (2.0–3.7 mA h cm⁻² at various rates). This work provides a proof-of-concept study on the rational design of interlayer materials in energy storage systems.
Agid:
6349980