Room temperature sodium-sulfur (Na-S) batteries hold great promise as the next-generation cost-effective energy storage systems. However, their practical implementation is still plagued by the low reversible capacity of a bulk-sized commercial sulfur cathode with low Coulombic efficiency and poor cycling stability. Here, we report a highly stable room temperature Na-S battery using a facile-processed, nanocarbon-promoted, bulk-sized commercial sulfur cathode and a polymer electrolyte. This processed nanocarbon possesses a high binding affinity to sulfur and polysulfides, largely facilitating the sulfur reaction kinetics and leading to high reversible capacity. Meanwhile, by applying a thin coating of the facile-processed nanocarbon on the polymer electrolyte, dead sulfur formation can be avoided, contributing to greatly enhanced capacity retention. Our Na-S battery delivers a reversible capacity of >700 mAh g⁻¹ with near-100% Coulombic efficiency and the ultrahigh capacity retention of 98.2% at 0.2C after 200 cycles.

室温钠硫（Na-S）电池作为下一代经济高效的储能系统具有广阔的前景。然而，它们的实际实施仍然受到具有低库仑效率和差的循环稳定性的大尺寸商业硫阴极的低可逆容量的困扰。在这里，我们报告了一种高度稳定的室温Na-S电池，它使用了易加工的，纳米碳促进的，大体积的商业化硫阴极和一种聚合物电解质。这种加工后的纳米碳对硫和多硫化物具有很高的结合亲和力，大大促进了硫的反应动力学并导致了高可逆容量。同时，通过在聚合物电解质上涂覆薄层处理的纳米碳，可以避免形成死硫，从而大大提高了容量保持率。^-1，库仑效率接近100％，200个循环后在0.2C下的超高容量保持率为98.2％。