Magnetron sputtering engineering of typha-like carbon nanofiber interlayer integrating brush filter and chemical adsorption for Li–S batteries

Abstract

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.