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

The two-dimensional transition metal dichalcogenides have wide application value in many fields. Herein, MoS 2 and WS 2 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 MoS 2 nanosheets. Then, Graphene aerogel composites are prepared with the exfoliated MoS 2 /WS 2 nanosheets, which loaded sulfur and employed as the cathode of Li-S batteries. TEM results reveal that MoS 2 /WS 2 nanosheets are embedded in reduced graphene oxide , and sulfur is evenly distributed in the composites. The composites containing MoS 2 /WS 2 nanosheets achieve outstanding electrochemical performance , during to the polysulfide adsorption capability of MoS 2 /WS 2 nanosheets and reducing the shuttle effect in Li-S batteries. It demonstrates a good application of exfoliated MoS 2 /WS 2 nanosheets in Li-S batteries.