Lithium–sulfur batteries (LSBs) are facing many challenges, such as the inadequate conductivity of sulfur, the shuttle effect caused by lithium polysulfide (LiPSs), lithium dendrites, and the flammability, which have hindered their commercial applications. Herein, a “four-in-one” functionalized coating is fabricated on the surface of polypropylene (PP) separator by using a

novel flame-retardant namely InC-HCTB to meet these challenges. InC-HCTB is obtained by cultivating polyphosphazene on the surface of carbon nanotubes with an in situ growth strategy. First, this unique architecture fosters an enhanced conductive network, bolstering the bidirectional enhancement of both ionic and electronic conductivities. Furthermore, InC-HCTB effectively inhibits the shuttle effect of LiPSs. LSBs exhibit a remarkable capacity of 1170.7 mA h g^?1 at 0.2 C, and the capacity degradation is a mere 0.0436% over 800 cycles at 1 C. Third, InC-HCTB coating serves as an ion migration network, hindering the growth of lithium dendrites. More importantly, InC-HCTB exhibits notable flame retardancy. The radical trapping action in the gas phase and the protective effect of the shielded char layer in the condensed phase are simulated and verified. This facile in situ growth strategy constructs a “four-in-one” functional separator coating, rendering InC-HCTB a promising additive for the large-scale production of safe and stable LSBs.

锂硫电池（LSB）面临着许多挑战，例如硫的导电性不足、多硫化锂（LiPS）引起的穿梭效应、锂枝晶和可燃性等，这些都阻碍了其商业应用。为此，我们利用新型阻燃剂InC-HCTB在聚丙烯（PP）隔膜表面制备了“四合一”功能化涂层来应对这些挑战。InC-HCTB是通过采用原位生长策略在碳纳米管表面培养聚磷腈而获得的。首先，这种独特的架构促进了增强的导电网络，支持离子和电子导电性的双向增强。此外，InC-HCTB有效抑制 LiPS 的穿梭效应。 LSB在0.2 C下表现出1170.7 mA hg^-1的卓越容量，并且在1C下800次循环后容量衰减仅为0.0436%。第三，InC-HCTB涂层充当离子迁移网络，阻碍了锂枝晶的生长。更重要的是，InC-HCTB表现出显着的阻燃性。模拟验证了气相中的自由基捕获作用和凝聚相中屏蔽炭层的保护作用。这种简便的原位生长策略构建了“四合一”功能隔膜涂层，使InC-HCTB成为大规模生产安全稳定LSB的有前景的添加剂。