Lithium–sulfur (Li–S) batteries are promising candidates for next-generation energy storage systems owing to their high energy density and low cost. However, critical challenges including severe shuttling of lithium polysulfides (LiPSs) and sluggish redox kinetics limit the practical application of Li–S batteries. Carbon nitrides (C_xN_y), represented by graphitic carbon nitride (g-C₃N₄), provide new opportunities for overcoming these challenges. With a graphene-like structure and high pyridinic-N content, g-C₃N₄ can effectively immobilize LiPSs and enhance the redox kinetics of S species. In addition, its structure and properties including electronic conductivity and catalytic activity can be regulated by simple methods that facilitate its application in Li–S batteries. Here, the recent progress of applying C_xN_y-based materials including the optimized g-C₃N₄, g-C₃N₄-based composites, and other novel C_xN_y materials is systematically reviewed in Li–S batteries, with a focus on the structure–activity relationship. The limitations of existing C_xN_y-based materials are identified, and the perspectives on the rational design of advanced C_xN_y-based materials are provided for high-performance Li–S batteries.

锂硫（Li-S）电池由于其高能量密度和低成本而成为下一代储能系统的有希望的候选者。然而，多硫化锂（LiPS）的严重穿梭和氧化还原动力学缓慢等关键挑战限制了锂硫电池的实际应用。以石墨碳氮化物（gC ₃ N ₄ ）为代表的碳氮化物（C _x N _y ）为克服这些挑战提供了新的机遇。 gC ₃ N ₄具有类石墨烯结构和高吡啶-N含量，可以有效固定LiPSs并增强S物种的氧化还原动力学。此外，其结构和性能（包括电子电导率和催化活性）可以通过简单的方法调节，从而促进其在锂硫电池中的应用。本文系统地综述了C _x N _y基材料（包括优化的gC ₃ N ₄ 、gC ₃ N ₄基复合材料以及其他新型C _x N _y材料）在Li-S电池中的应用最新进展，重点关注关于结构-活性关系。识别了现有C _x N _y基材料的局限性，并为高性能锂硫电池的先进C _x N _y基材料的合理设计提供了视角。