Advanced two-dimensional materials toward polysulfides regulation of metal–sulfur batteries

Metal–sulfur battery, which provides considerable high energy density at a low cost, is an appealing energy-storage technology for future long-range electric vehicles and large-scale power grids. One major challenge of metal–sulfur batteries is their long-term cycling stability, which is significantly deteriorated by the generation of various soluble polysulfide intermediates and the shuttling of these intermediates through the separator. Furthermore, the intrinsically sluggish reaction kinetics associated with the poor conductivity of sulfur/sulfides family causes a large polarization in cycle behavior, which further deteriorates the electrode rechargeability. To solve these problems, the research communities have spent a great amount of effort on designing smart cathodes to delicately tailor the physiochemical interaction between the sulfur hosts and polysulfides. Here, we summarize the key progress in the development of two-dimensional (2D) host materials showing advantageous tunability of their physiochemical properties through coordination control methods such as defect engineering, heteroatom doping, heterostructure, and phase and interface engineering. Accordingly, we discuss the mechanisms of polysulfide anchoring and catalyzing upon specific coordination environment in conjunction with possible structure–property relationships and theoretical analysis. This review will provide prospective fundamental guidance for future sulfur host design and beyond.