Lithium–Sulfur Battery Cathode Design: Tailoring Metal‐Based Nanostructures for Robust Polysulfide Adsorption and Catalytic Conversion

Abstract

Lithium–sulfur (Li‐S) batteries have a high specific energy capacity and density of 1675 mAh g−1 and 2670 Wh kg−1, respectively, rendering them among the most promising successors for lithium‐ion batteries. However, there are myriads of obstacles in the practical application and commercialization of Li‐S batteries, including the low conductivity of sulfur and its discharge products (Li 2 S/Li 2 S 2), volume expansion of sulfur electrode, and the polysulfide shuttle effect. Hence, immense attention has been devoted to rectifying these issues, of which the application of metal‐based compounds (i.e., transition metal, metal phosphides, sulfides, oxides, carbides, nitrides, phosphosulfides, MXenes, hydroxides, and metal‐organic frameworks) as sulfur hosts is profiled as a fascinating strategy to hinder the polysulfide shuttle effect stemming from the polar–polar interactions between the metal compounds and polysulfides. This review encompasses the fundamental electrochemical principles of Li‐S batteries and insights into the interactions between the metal‐based compounds and the polysulfides, with emphasis on the intimate structure–activity relationship corroborated with theoretical calculations. Additionally, the integration of conductive carbon‐based materials to ameliorate the existing adsorptive abilities of the metal‐based compound is systematically discussed. Lastly, the challenges and prospects toward the smart design of catalysts for the future development of practical Li‐S batteries are presented.