Low‐Bandgap Se‐Deficient Antimony Selenide as a Multifunctional Polysulfide Barrier toward High‐Performance Lithium–Sulfur Batteries

Abstract The shuttling behavior and sluggish conversion kinetics of the intermediate lithium polysulfides (LiPSs) represent the main obstructions to the practical application of lithium–sulfur (Li–S) batteries. Herein, an anion‐deficient design of antimony selenide (Sb 2 Se 3− x ) is developed to establish a multifunctional LiPS barrier toward the inhibition of polysulfide shuttling and enhancement of battery performance. The defect chemistry in the as‐developed Sb 2 Se 3− x promotes the intrinsic conductivity, strengthens the chemical affinity to LiPSs, and catalyzes the sulfur electrochemical conversion, which are verified by a series of computational and experimental results. Attributed to these unique superiorities, the obtained LiPS barrier efficiently promotes and stabilizes the sulfur electrochemistry, thus enabling excellent Li–S battery performance, e.g., outstanding cyclability over 500 cycles at 1.0 C with a minimum capacity fading rate of 0.027% per cycle, a superb rate capability up to 8.0 C, and a high areal capacity of 7.46 mAh cm −2 under raised sulfur loading. This work offers a defect engineering strategy toward fast and durable sulfur electrochemistry, holding great promise in developing practically viable Li–S batteries as well as enlightening the material design of related energy storage and conversion systems.