Manipulating Electrocatalytic Li2S Redox via Selective Dual‐Defect Engineering for Li–S Batteries

Lithium–sulfur (Li–S) batteries are promising candidates for next‐generation energy storage, yet they are plagued by the notorious polysulfide shuttle effect and sluggish redox kinetics. While rationally designed redox mediators can facilitate polysulfide conversion, favorable bidirectional sulfur electrocatalysis remains a formidable challenge. Herein, selective dual‐defect engineering (i.e., introducing both N‐doping and Se‐vacancies) of a common MoSe2 electrocatalyst is used to manipulate the bidirectional Li2S redox. Systematic theoretical prediction and detailed electrokinetic analysis reveal the selective electrocatalytic effect of the two types of defects, thereby achieving a deeper mechanistic understanding of the bidirectional sulfur electrochemistry. The Li–S battery using this electrocatalyst exhibits excellent cyclability, with a low capacity decay rate of 0.04% per cycle over 1000 cycles at 2.0 C. More impressively, the potential for practical applications is highlighted by a high areal capacity (7.3 mAh cm−2) and the construction of a flexible pouch cell. Such selective electrocatalysis created by dual‐defect engineering is an appealing approach toward working Li–S systems. A common MoSe2 electrocatalyst synergizing N‐doping and Se‐vacancies enables optimal Li2S electrocatalytic manipulation toward favorable bidirectional sulfur redox chemistry with high electrocatalytic selectivity, accordingly achieving excellent rate performance, cycling stability, and areal capacity in pursuit of working Li–S batteries.