Tuning the D-Band Center of Bi2S3─MoS2 Heterostructure Towards Superior Lithium-Sulfur Batteries.

Abstract

Lithium-sulfur (Li-S) batteries are one of the most promising energy storage devices due to their environmental friendliness, low cost, and high specific capacity. However, the slow electrochemical kinetics and the "shuttle effect" have seriously hindered their commercialization. Herein, the nanoflower Bi2S3─MoS2 (BMS) heterostructure is synthesized by a two-step hydrothermal method, and then the Bi2S3─MoS2-Polypropylene (BMS-PP) interlayer is constructed. The heterostructure is rich in active sites, in which BMS has strong adsorption to lithium polysulfides (LiPSs) and can effectively anchor LiPSs while catalyzing LiPSs and promote the redox of Li2S at the same time, which can improve the utilization of active substances. More importantly, the d-band center can be tuned by the formation of Bi2S3─MoS2 heterostructure. Thus, Li-S batteries containing the BMS-PP interlayer show excellent rate performance (841.6 mAh g-1 at 5 C) and cycling performance (70.3% capacity retention after 500 cycles at 3 C). This work provides a new route for high-performance lithium-sulfur batteries.