Boron Vacancy Engineering in 2D WB‐Based MBene Catalysts for Optimizing Lithium Polysulfide Reactions

Abstract The shuttle effect of lithium polysulfides (LiPSs) and the slow conversion kinetics of sulfur have been hindering the commercial development of lithium–sulfur (Li–S) batteries. Herein, WB‐V B based 2Dl MBene catalyst containing B vacancies is successfully prepared by a one‐step room temperature F‐free etching method. Both W and B atoms in this catalyst can interact with LiPSs simultaneously, effectively inhibiting the diffusion of soluble LiPSs. B‐vacancy construction not only provides more exposure of active site W, but also improves the d band center, which is conducive to the rapid adsorption and Li–S reaction kinetics. More importantly, its mechanism for catalyzing LiPS reaction is characterized by in situ X‐ray absorption spectroscopy. The results show that the reversible capacity is as high as 1485 mAh g −1 at 0.2 C, and 664 mAh g −1 even at 4 C. Furthermore, an outstanding capacity of 4.15 mAh cm −2 under high load of 4.36 mg cm −2 has remarkable cyclic stability.