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

ABSTRACT

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.