Sc2CO-MXene/h-BN heterostructure with synergetic effect as an anchoring and catalytic material for lithium-sulfur battery

Abstract

The commercialization of lithium-sulfur (Li-S) battery is primarily hindered by several challenges, including the poor cycling stability derived from the severe shuttling of lithium polysulfides (LiPSs) and sluggish electrode kinetics. Fabricating heterostructure is an increasing strategy to overcome these problems, but the design mechanism is still an open issue. Herein, using the Sc2CO-MXene/h-BN heterostructure as a prototype, we illuminate how the fabrication of heterostructure effectively LiPS conversion and improve sulfur utilization by first principles calculations. Our outcomes highlight that compared with the individual layers, Sc2CO-MXene/h-BN heterostructure exhibits a stronger affinity toward LiPS to suppress the shuttling effect, which is mostly originated from the interlayer polarity in heterostructure. Meanwhile, Sc2CO-MXene/h-BN heterostructure possesses an ultra-low diffusion barrier (0.71 eV) and decomposition barrier (1.29 eV) of Li2S cluster, which balances the catalytic activity and trapping ability toward LiPSs. Further results on the electronic structures indicate that even after LiPSs adsorption, an enhanced electronic conductivity can be achieved by fabricating Sc2CO-MXene/h-BN heterostructure, which is highly desired to stimulate the redox electrochemistry of LiPSs by providing electronic pathways. We believe that the present discovery pioneers the application of Sc2CO-MXene/h-BN as anchoring and catalytic material for Li-S battery can provide a developed insight on the design of heterostructure cathodes in Li-S battery.