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Lithium–sulfur (Li–S) batteries are one of the most promising next‐generation batteries owing to their ultra‐high theoretical energy density and that sulfur is an abundant resource. During the past 20 years, various sulfur materials have been reported. As a molecular‐scale sulfur‐composite cathode, sulfurized pyrolyzed poly(acrylonitrile) (S@pPAN) exhibits several competitive advantages in terms of its electrochemical behavior. Although it was first reported in 2002 S@pPAN is currently attracting increasing attention. In this Minireview, we summarize its molecular model and explore the correlation between its structure and its exceptional electrochemical performance. We classify the modification strategies into three types, including material improvement, binder, and electrolyte screening. Several research and development directions are also suggested.

Safety concerns pose a significant challenge for the large‐scale employment of lithium–sulfur batteries. Extremely flammable conventional electrolytes and dendritic lithium deposition cause severe safety issues. Now, an intrinsic flame‐retardant (IFR) electrolyte is presented consisting of 1.1 m lithium bis(fluorosulfonyl)imide in a solvent mixture of flame‐retardant triethyl phosphate and high flashpoint solvent 1,1,2,2‐tetrafluoroethyl‐2,2,3,3‐tetrafluoropropyl (1:3, v/v) for safe lithium–sulfur (Li−S) batteries. This electrolyte exhibits favorable flame‐retardant properties and high reversibility of the lithium metal anode (Coulombic efficiency >99 %). This IFR electrolyte enables stable lithium plating/stripping behavior with micro‐sized and dense‐packing lithium deposition at high temperatures. When coupled with a sulfurized pyrolyzed poly(acrylonitrile) cathode, Li−S batteries deliver a high composite capacity (840.1 mAh g−1) and high sulfur utilization of 95.6 %.

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