MoS₂@C-Modified Separator as an Efficient Polysulfide Barrier for High-Performance Li–S Batteries

Due to the promising energy density (2800 Wh kg^-1) and high theoretical specific capacity (1675 mAh g^-1), there has been significant research interest in lithium-sulfur batteries (LSBs) recently. However, the shuttle effect and sluggish redox kinetics impede the commercial application of LSBs. In this work, a MoS₂@C interlayer-modified commercial polypropylene (PP) (MoS₂@C-PP) separator is designed to improve the electrochemical performance of LSBs. The active sites provided by MoS₂ are conducive to enhancing the absorption of polysulfide lithium and improving the electrochemical performance. The N-doped carbon not only facilitates electrolyte penetration but also enhances ion transfer to promote reaction kinetics. Additionally, the formation of C-S bonds significantly reduces the shuttle effect. These factors largely accelerate the redox kinetics and decrease the shuttle effect, thereby improving the electrochemical performance of LSBs. As a consequence, the LSB with the MoS₂@C-PP separator achieves a high discharge capacity of 860.5 mAh g^-1 at 0.5 C after 200 cycles and a superior rate performance of 711.5 mAh g^-1 at 2 C. This work offers a promising direction for enhancing the electrochemical performance of LSBs through separator modification .