Effects of Catalysis and Separator Functionalization on High-Energy Lithium-Sulfur Batteries: A Complete Review

Lithium-sulfur (Li-S) batteries have the advantages of high theoretical specific capacity (1675 mAh g(-1)), rich sulfur resources, low production cost, and friendly environment, which makes it one of the most promising next-generation rechargeable energy storage devices. However, the "shuttle effect" of polysulfide results in the passivation of metal lithium anode, the decrease of battery capacity and coulombic efficiency, and the deterioration of cycle stability. To realize the commercialization of Li-S batteries, its serious "shuttle effect" needs to be suppress. The commercial separators are ineffective to suppress this effect because of its large pore size. Therefore, it is an effective strategy to modify the separator surface and introduce functional modified layer. In addition to the blocking strategy, the catalysis of polysulfide conversion reaction is also an important factor hindering the migration of polysulfides. In this review, the principles of separator modification, functionalization, and catalysis in Li-S batteries are reviewed. Furthermore, the research trend of separator functionalization and polysulfide catalysis in the future is prospected.