Preparation of MoS2/WS2 nanosheets by liquid phase exfoliation with assistance of epigallocatechin gallate and study as an additive for high-performance lithium-sulfur batteries

Hang Zhao; Hao Wu; Jinhua Wu; Jianlong Li; Yujie Wang; Yun Zhang; Heng Liu

doi:10.1016/j.jcis.2019.05.080

Preparation of MoS₂/WS₂ nanosheets by liquid phase exfoliation with assistance of epigallocatechin gallate and study as an additive for high-performance lithium-sulfur batteries

J Colloid Interface Sci. 2019 Sep 15:552:554-562. doi: 10.1016/j.jcis.2019.05.080. Epub 2019 May 25.

Authors

Hang Zhao¹, Hao Wu², Jinhua Wu³, Jianlong Li², Yujie Wang⁴, Yun Zhang², Heng Liu⁵

Affiliations

¹ Department of Advanced Energy Materials, College of Materials Science and Engineering, Sichuan University, Chengdu 610064, PR China; International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, PR China.
² Department of Advanced Energy Materials, College of Materials Science and Engineering, Sichuan University, Chengdu 610064, PR China.
³ Department of Advanced Energy Materials, College of Materials Science and Engineering, Sichuan University, Chengdu 610064, PR China; Department of Materials Engineering, Sichuan College of Architectural Technology, Deyang 618000, PR China.
⁴ Department of Advanced Energy Materials, College of Materials Science and Engineering, Sichuan University, Chengdu 610064, PR China; Research Institute of Natural Gas Technology, Petrochina Southwest Oil & Gas Field Company, Chengdu 610213, PR China.
⁵ Department of Advanced Energy Materials, College of Materials Science and Engineering, Sichuan University, Chengdu 610064, PR China. Electronic address: h_liu@scu.edu.cn.

PMID: 31154248
DOI: 10.1016/j.jcis.2019.05.080

Abstract

The two-dimensional transition metal dichalcogenides have wide application value in many fields. Herein, MoS₂ and WS₂ nanosheets are produced by liquid phase exfoliation method assisted by epigallocatechin gallate. The effects of epigallocatechin gallate concentration and stripping time are investigated by UV-vis. The morphology and structure characterization of exfoliated nanosheets are studied by XRD, Raman, SEM, HRTEM and AFM, the results showing that the nanosheets have few layers and the exfoliated solution is homogeneous dispersion and stable. The exfoliated nanosheets produced by 2 mg ml^-1 epigallocatechin gallate solution for 12 h have five monolayers approximately, presenting a phase transformation from 2H to 1T structure of MoS₂ nanosheets. Then, Graphene aerogel composites are prepared with the exfoliated MoS₂/WS₂ nanosheets, which loaded sulfur and employed as the cathode of Li-S batteries. TEM results reveal that MoS₂/WS₂ nanosheets are embedded in reduced graphene oxide, and sulfur is evenly distributed in the composites. The composites containing MoS₂/WS₂ nanosheets achieve outstanding electrochemical performance, during to the polysulfide adsorption capability of MoS₂/WS₂ nanosheets and reducing the shuttle effect in Li-S batteries. It demonstrates a good application of exfoliated MoS₂/WS₂ nanosheets in Li-S batteries.

Keywords: Free-standing electrode; Liquid phase exfoliation; Lithium-sulfur battery; MoS(2); Nanosheets; WS(2).