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.