Suppressing nucleation barrier and shuttle effect of lithium‑sulfur batteries cathode via d-band tailored Ni_xCo_9-xS₈/carbon hollow nanofibers

AbstractAlthough lithium‑sulfur batteries (LSBs) have high energy density and low cost, they face challenges including lithium polysulfides (LiPSs) shuttling, poor sulfur conductivity, volume expansion, and sluggish redox kinetics. To address limitations, a dual-optimization strategy where Ni_xCo_9-xS₈ serves as the primary catalyst for redox conversion, while the hierarchically confined hollow carbon nanofiber matrix suppresses shuttling and enhances conductivity. We prepared a nickel-doped cobalt sulfide catalyst confined within hollow carbon nanofibers (Ni_xCo_9-xS₈@HCNFs) through a solvothermal synthesis, coaxial electrospinning and controlled carbonization process. The doping of Ni into the Co₉S₈ lattice upshifts d-band center that facilitates electron transfer to SS bonds in LiPSs, elongating bond lengths and accelerating Li₂S deposition kinetics. The Ni_xCo_9-xS₈@HCNFs/S cathode exhibited high initial capacity of 1168.7 mAh g−1 at 0.5C with low decay, remarkable rate capability. The design maintains stability under practical conditions, demonstrating efficient LiPSs confinement and catalytic conversion critical for viable LSBs.