2H‐Phase Molybdenum Diselenide/Hollow Carbon Sphere‐Based Separator With “One‐Stone‐Two‐Birds” Effect Boosting High‐Performance Lithium‐Sulfur Batteries

ABSTRACT Lithium‐sulfur batteries (LSBs) offer advantages such as high energy density, cost‐effectiveness, and abundant sulfur resources and therefore are regarded as ideal large‐scale energy storage systems. However, due to the shuttle effect caused by the dissolution of soluble lithium polysulfides (LiPSs) into the electrolyte, LSBs face issues of low reversible capacity and rapid capacity decay. To overcome this limitation, a multifunctional polypropylene separator is developed by 2hexagonal‐phase molybdenum diselenide (2H‐MoSe 2 ) functionalized hollow carbon spheres through a coating method. 2H‐MoSe 2 strongly interacts with soluble LiPSs, enhancing their redox dynamics and improving sulfur utilization. Additionally, density functional theory (DFT) calculations reveal that the diffusion barrier for Li ions on the 2H‐MoSe 2 surface is minimal, facilitating efficient lithium‐ion transport. Furthermore, hollow carbon spheres physically restrict the dissolution of soluble LiPSs. This multifunctional separator exhibits excellent electrochemical performance in LSBs, achieving a high reversibility of 800 mAh g −1 at 1.0 C after 1500 cycles. This investigation presents an efficacious approach to the development of a functional separator with shuttle suppression capabilities.