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 .