Porous carbons have previously been widely used as host materials for sulfur (S) electrodes because of their high conductivity and high surface area. However, they generally lack strong chemical affinity to stabilize polysulfide species. Therefore, conducting polymers have been employed to stabilize S electrodes. Integrating conducting polymers with high-surface-area carbons can create a new materials platform and synergize their functions. However, the previously used conducting polymers were often insoluble, and coating them uniformly from solution onto a nonpolar carbon substrate is a challenge. Here, we report that solution-processable isoindigo-based polymers incorporating polar substituents provide critical features: (1) the conjugated backbone provides good conductivity; (2) functional pyridine groups provide high affinity to polysulfide species; and (3) they possess high solubility in organic solvents. These lead to effective coating on various carbonaceous substrates to provide highly stable sulfur electrodes. Importantly, the electrodes exhibit good capacity retention (80% over 300 cycles) at sulfur mass loading of 3.2 mg/cm², which significantly surpasses the performance of others reported in polymer-enabled sulfur cathodes.

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通过有效结合吡啶官能化聚合物提高硫电极的循环稳定性

多孔碳由于其高导电性和高表面积，以前已被广泛用作硫（S）电极的主体材料。但是，它们通常缺乏强大的化学亲和力来稳定多硫化物。因此，已经使用导电聚合物来稳定S电极。将导电聚合物与高表面积碳集成在一起可以创建一个新的材料平台，并发挥其功能。然而，先前使用的导电聚合物通常是不溶的，将其从溶液均匀地涂覆到非极性碳基材上是一个挑战。在这里，我们报道结合了极性取代基的可溶液加工的基于靛蓝的聚合物具有以下关键特征：（1）共轭骨架具有良好的导电性；（2）吡啶官能团对多硫化物具有高亲和力；（3）它们在有机溶剂中具有高溶解度。这些导致在各种含碳基材上的有效涂层，以提供高度稳定的硫电极。重要的是，在硫的质量负载为3.2 mg / cm时，电极表现出良好的容量保持率（300次循环中80％）^{如图2所示}，其显着超过了聚合物使能的硫阴极中报道的其他性能。