Facile and Effective Strategy to Encapsulate Sulfur Particles for High-Performance Lithium-Sulfur Battery

A sulfur composite (poly@S) was prepared by in situ encapsulating the copolymer of 1,3-dioxolane (DOL) and trioxymethylene (TOM) (poly(DOL-co-TOM)) on the surface of S particles, which was used as cathode material for Li-S battery. The poly(DOL-co-TOM) copolymer has high ionic conductivity and excellent tensile properties, which can promote reaction kinetics and stabilize the cathode structure. The ultrathin encapsulation layer (similar to 40 nm) can effectively confine the polysulfides and alleviate the "shuttle effect". The Li-S battery assembled with the poly@S composite cathode shows outstanding cycle stability (a low decay rate of about 0.079% per cycle at 0.5 C over 400 cycles) and excellent C-rate performance. Moreover, the self-discharge has been effectively restricted by inhibiting the shuttling of polysulfides. This work creatively proposes a facile and effective strategy to prepare a composite S cathode for high-performance Li-S batteries.