Functional Separator Modified with Reduced Graphene Oxide and Fe₃S₄ for High-Performance Lithium–Sulfur Batteries

In recent years, due to energy shortage and environmental pollution, lithium–sulfur batteries (LSBs) with low cost, high energy density, and environmentally friendly characteristic have attracted wide attention. However, the shuttle effect caused by lithium polysulfides (LiPSs) greatly reduces the cycle performance and life of LSBs. To solve this problem, we design an Fe 3 S 4 /rGO composite by the one-step hydrothermal method, which is used to modify the polypropylene (PP) separator. The Fe 3 S 4 /rGO composite has high electronic conductivity and adsorption performance, which provides channels for electron transfer and effectively inhibits the shuttle of LiPSs. The lithium–sulfur battery assembled with an Fe 3 S 4 /rGO-PP separator possesses the satisfactory specific capacities. The first discharge capacity reaches 1293 mAh g –1 at 0.2 C, and the discharge capacity maintains at 750 mAh g –1 after 100 cycles. After 300 cycles at 1 C, the discharge capacity is 578 mAh g –1, and the average capacity attenuation rate per cycle is 0.052%. These results indicate that the Fe 3 S 4 /rGO-PP separator would have a good application prospect for high-performance LSBs.