Nanostructure Engineering Strategies of Cathode Materials for Room-Temperature Na–S Batteries

Room-temperature sodium–sulfur (RT Na–S) batteries are considered to be a competitive electrochemical energy storage system, due to their advantages in abundant natural reserves, inexpensive materials, and superb theoretical energy density. Nevertheless, RT Na–S batteries suffer from a series of critical challenges, especially on the S cathode side, including the insulating nature of S and its discharge products, volumetric fluctuation of S species during the (de)­sodiation process, shuttle effect of soluble sodium polysulfides, and sluggish conversion kinetics. Recent studies have shown that nanostructural designs of S-based materials can greatly contribute to alleviating the aforementioned issues via their unique physicochemical properties and architectural features. In this review, we review frontier advancements in nanostructure engineering strategies of S-based cathode materials for RT Na–S batteries in the past decade. Our emphasis is focused on delicate and highly efficient design strategies of material nanostructures as well as interactions of component–structure–property at a nanosize level. We also present our prospects toward further functional engineering and applications of nanostructured S-based materials in RT Na–S batteries and point out some potential developmental directions.