Enhancing the adsorption and catalytic conversion of polysulfides is critical in improving the cycling stability of lithium–sulfur (Li–S) batteries. Herein, an ultralight typha-like carbon nanofiber (CNF) based interlayer (MoS₂/Al₂O₃@CNF) is constructed by scalable electrospinning and eco-friendly magnetron sputtering, to act as a “police constable” between the cathode and separator. The co-sputtering of MoS₂ and Al₂O₃ endows the interlayer with both chemical adsorption and catalytic conversion active sites. Besides, the typha-like nanofibrous interlayer serves as both membrane and brush filters, leading to more efficient polysulfide blocking. The structural superiority of this interlayer compared to the CNF membrane results in a 693.8% higher specific surface area of 254 m² g⁻¹. In addition to these benefits, the unique structure allows for a 6.9-fold increase in exposure of active sites. The cell with such an interlayer delivers stable long-term cycling performance with an ultralow capacity decay rate of 0.035% per cycle over 1000 cycles at 0.5C. The long-term cycling performance can be attribute to the structural stability of the typha-like nanofibrous membrane, as evidenced by the postmortem SEM images. This work provides a valuable strategy for designing functional interlayers toward the long-term cycling stable Li–S batteries.