Electrospun MoS₂-CNTs-PVA/PVA Hybrid Separator for High-Performance Li/FeS₂ Batteries

As a promising candidate for high-energy-density rechargeable lithium metal batteries, Li/FeS₂ batteries still suffer from the large volume change and severe shuttle effect of lithium polysulfides during cycling. To improve the electrochemical performance, great efforts have been made to modify FeS₂ cathodes by constructing various nanocomposites. However, energy density is sacrificed, and these materials are not applicable at a large scale. Herein, we report that the electrochemical performance of commercial FeS₂ can be greatly enhanced with the application of a double-layer MoS₂-CNTs-PVA (MCP)/PVA separator fabricated by electrospinning. The assembled Li/FeS₂ batteries can still deliver a high discharge capacity of 400 mAh/g after 200 cycles at a current density of 0.5 C. The improved cycling stability can be attributed to the strong affinity towards lithium polysulfides (LiPSs) of the hydroxyl-rich PVA matrix and the unique double-layer structure, in which the bottom layer acts as an electrical insulation layer and the top layer coupled with MoS₂/CNTs provides catalytic sites for LiPS conversion.