The notorious issues of polysulfide shuttling behaviour and sluggish redox kinetics seriously hamper the practical applications of lithium-sulfur (Li-S) batteries. In this work, catalytic FeSe₂ nanoparticles encapsulated with carbon nanoboxes (FeSe₂@C NBs) that derived from the selenide reaction of yolk-shelled Fe₃O₄@C are proposed as a multifunctional sulfur host to restrain the polysulfide shuttle effect and accelerate the polysulfide redox conversion. The experimental results display that the S/FeSe₂@C cathode exhibits better sulfur utilization, higher rate performance, and longer cycle life compared to S/Fe₃O₄@C cathode. Even after 700 cycles at 1C, an ultralow capacity decay of 0.04% per cycle of S/FeSe₂@C cathode can still be maintained. The density functional theory (DFT) calculations reveal that FeSe₂@C NBs possess stronger chemical affinity to polysulfides and lower energy gap between bonding and antibonding orbitals, which could promote the interfacial charge transfer kinetics, thus enabling better Li-S battery performance.

多硫化物穿梭行为和缓慢的氧化还原动力学的臭名昭著的问题严重阻碍了锂硫（Li-S）电池的实际应用。在这项工作中，提出了由卵黄壳的Fe ₃ O ₄ @C的硒化物反应衍生的碳纳米盒（FeSe ₂ @C NBs）包裹的催化FeSe ₂纳米颗粒作为多功能硫基质，可抑制多硫化物的穿梭作用并加速多硫化物的氧化还原转化率。实验结果表明，与S / Fe ₃ O ₄相比，S / FeSe ₂ @C阴极具有更好的硫利用率，更高的倍率性能和更长的循环寿命。@C阴极。即使在1C下进行700次循环后，仍可保持S / FeSe ₂ @C阴极每循环0.04％的超低容量衰减。密度泛函理论（DFT）计算表明，FeSe ₂ @C NBs对多硫化物具有更强的化学亲和力，键合和反键合轨道之间的能隙较小，这可以促进界面电荷转移动力学，从而实现更好的Li-S电池性能。