Lightweight Reduced Graphene Oxide@MoS₂ Interlayer as Polysulfide Barrier for High-Performance Lithium–Sulfur Batteries

Abstract

The further development of lithium-sulfur (Li-S) batteries is limited by the fact that the soluble polysulfide leads to the shuttle effect, thereby reducing the cycle stability and cycle life of the batteries. To address this issue, here a thin and lightweight (8 μm and 0.24 mg cm^-2) reduced graphene oxide@MoS₂ (rGO@MoS₂) interlayer between the cathode and the commercial separator is developed as a polysulfide barrier. The rGO plays the roles of both a polysulfide physical barrier and an additional current collector, while MoS₂ has a high chemical adsorption for polysulfides. The experiments demonstrate that the Li-S cell constructed with an rGO@MoS₂-coated separator shows a high reversible capacity of 1122 mAh g^-1 at 0.2 C, a low capacity fading rate of 0.116% for 500 cycles at 1 C, and an outstanding rate performance (615 mAh g^-1 at 2 C). Such an interlayer is expected to be ideal for lithium-sulfur battery applications because of its excellent electrochemical performance and simple synthesis process.