Among the emerging ‘beyond lithium-ion’ technologies for maximized sustainability, lithium–sulfur (Li–S) is a favoured chemistry because of its exceptional energy density from the conversion of sulfur, an element in abundant supply. However, the dissolution of several intermediate polysulfides formed during conversion leads to rapid performance degradation over cycling. Here we address this issue by sulfurizing a hybrid polymer network with polyphosphazene and carbon as a cathode for Li–S batteries. With rich sites to re-bond and adsorb dissociative sulfur species, this hybrid polymer network circumvents the formation of soluble polysulfides and enables a unique, reversible inserting conversion reaction. Thus, our cathode delivers both high capacity (~900 mAh g⁻¹_cathode) and excellent cycling stability in Li–S coin cells, with a pouch cell demonstration of projected energy density of ~300 Wh kg⁻¹ and 84.9% capacity retention after 150 cycles. The strategy can be extended to other cost-effective, recyclable polymers, advancing sulfur-based batteries towards practical energy storage application.

在旨在实现最大可持续性的新兴“超越锂离子”技术中，锂硫 （Li-S） 是一种受欢迎的化学成分，因为它通过硫（一种供应丰富的元素）的转化而具有非凡的能量密度。然而，转化过程中形成的几种中间多硫化物的溶解会导致循环性能迅速下降。在这里，我们通过用聚磷腈和碳硫化杂化聚合物网络作为 Li-S 电池的阴极来解决这个问题。这种杂化聚合物网络具有丰富的位点，可重新键合和吸附解离硫物质，可避免可溶性多硫化物的形成，并实现独特的可逆插入转化反应。因此，我们的阴极在 Li-S 纽扣电池中提供了高容量（~900 mAh ^g-1_阴极）和出色的循环稳定性，软包电池的预计能量密度为 ~300 Wh ^kg-1,150 次循环后容量保持率为 84.9%。该策略可以扩展到其他具有成本效益的可回收聚合物，推动硫基电池走向实际的储能应用。