Enhanced polysulfide adsorption and conversion on FeS2@CNF-modified separator for Li–S batteries

Abstract

Lithium–sulfur (Li–S) batteries have garnered extensive attention owing to their remarkable theoretical capacity and cost-effectiveness. Nevertheless, their practical commercialization has been hindered by the pronounced shuttle effect and sluggish redox reaction kinetics. Herein, a carbon nanofiber (FeS₂@CNF) functionalized with FeS₂ nanoparticles was developed as a high-performance separator for Li–S batteries, enabling efficient polysulfide adsorption, enhanced redox kinetics, and effective mitigation of the shuttle effect. Consequently, the Li–S cell employing FeS₂@CNF demonstrates an outstanding initial specific capacity of 1455.3 mAh g⁻¹ at 0.5C, retaining 864.5 mAh g⁻¹ after 350 cycles with an ultralow capacity decay rate of just 0.16%. This work offers a promising strategy for the rational design of advanced separators in Li–S batteries.