Mitigation of Polysulfide Shuttling in Lithium‐Sulfur Batteries Utilizing Vanadium Pentoxide/Polypyrrole Nanocomposite Separators

Lithium‐sulfur (Li‐S) batteries are promising energy storage devices due to their high theoretical energy density and cost‐effectiveness. However, the shuttle effect of polysulfides during the charging and discharging processes leads to a rapid decline in capacity, thereby restricting their application in energy storage. The separator, a crucial component of Li‐S batteries, facilitates the transport of Li+ ions. However, the large pores present on the surface of the separator are insufficient to prevent the shuttling effect of polysulfides. This paper proposes a straightforward coating method to introduce a vanadium pentoxide (V2O5) /polypyrrole (PPy) functional coating on the surface of a conventional polymer separator. The unique composition of the V2O5/PPy layer plays an essential role in effectively preventing the bidirectional movement of polysulfides and the subsequent formation of inactive sulfur. Compared to those using polypyrrole separators,when equipped with a V2O5/PPy separator, the capacity retention after 100 cycles was recorded at 98%, with a measured rate of capacity degradation at just 0.016%, despite the sulfur content being as high as 1.84 mg cm⁻². Furthermore, after 400 cycles at 1C, the capacity retention rate reached 57.6%. The thoughtful design of this modified separator represents an effective strategy for improving the performance of Li‐S batteries.