Room-temperature sodium-sulfur batteries have attracted extensive attention as a cost-effective and high theoretical energy density next-generation energy storage systems. However, the insulating nature of sulfur, the sluggish reactivity of sulfur with sodium, and severe dissolution of polysulfide are the main challenges of this technology. Here, we propose a covalent sulfur bond breakage mechanism by bonding of sulfur chain onto the inner cavity of the sulfydryl-functionalized mesoporous hollow carbon spheres (MHCS) to efficiently promote the generation of short-chain sodium polysulfide and accelerate polysulfide redox kinetics. The covalent sulfur confined MHCS (S@MHCS) cathode delivers an unprecedented rate capability (250 mAh g⁻¹ at 5 C) and exhibits excellent long-term cycling stability over 1000 cycles at 1 C with a high cathode loading of 5 mg cm⁻². Moreover, the associated electrochemical reaction mechanism is also revealed by ex-situ X-ray photoelectron spectroscopy and theoretical calculation. This work introduces a novel sulfur cathode design to enhance the performance of room-temperature sodium-sulfur batteries.

室温钠硫电池作为一种高性价比、高理论能量密度的下一代储能系统受到了广泛关注。然而，硫的绝缘性、硫与钠的缓慢反应性以及多硫化物的严重溶解是该技术的主要挑战。在这里，我们提出了一种共价硫键断裂机制，通过将硫链键合到巯基功能化介孔空心碳球（MHCS）的内腔上，有效促进短链多硫化钠的生成并加速多硫化物氧化还原动力学。共价硫限制的 MHCS (S@MHCS) 阴极提供了前所未有的倍率能力 (250 mAh g ^{−15 C），并在 1 C 和 5 mg cm -2}的高阴极负载下表现出超过 1000 次循环的优异长期循环稳定性。此外，通过异位X射线光电子能谱和理论计算也揭示了相关的电化学反应机理。这项工作引入了一种新颖的硫阴极设计，以提高室温钠硫电池的性能。