Inducing Rapid Polysulfide Transformation through Enhanced Interfacial Electronic Interaction for Lithium-Sulfur Batteries

Sluggish dynamics of polysulfides conversion leads to reduced utilization of active sulfur and rapid capacity decay. Introducing catalysts into lithium-sulfur battery systems is a feasible and imperative strategy to tackle this problem. Previously researches have mainly been focused on selecting new catalysts and design functional structures to improve performance, whereas ignoring the interaction between catalysts and their carriers. Herein, by simply fabricating high-efficiency ZnS quantum dot @ graphene nanosheet catalyst (ZnS QD@rGO), we utilized enhanced interfacial electronic interaction to accelerate polysulfide conversion for high energy density Li-S batteries. With the smaller size of ZnS, the interfacial electronic interaction gets more enhanced, which was evidenced by DFT calculations and XPS experiments. After mixing with sulfur, the electrodes achieve a high capacity of 857.8 mAh g-1 at 1C and retention of 91.2% after 300 cycles. Also, a sulfur cathode with a high actual capacity of ~4.0 mAh cm−2 could be obtained, which shows a 100 stable round trip. We believe this strategy represents a new perspective on designing efficient high-load electrodes for Li-S batteries.