FeS2 intercalated montmorillonite as a multifunctional separator coating for high-performance lithium–sulfur batteries

Abstract

It is a rising strategy to construct a multifunctional separator coating with cheap and abundant resources to promote the practical applications of lithium–sulfur (Li–S) batteries. Herein, a novel FeS₂ intercalated montmorillonite (FeS₂@MMT) is designed as a multifunctional separator coating to anchor lithium polysulfides (LiPSs), catalyze LiPS redox reactions, and accelerate ion transport and electron transfer at the interface between the separator and the cathode. In addition, the FeS₂@MMT coating layer also endows the modified separator with high thermal stability and electrolyte affinity. Consequently, Li–S cells with FeS₂@MMT/PP (polypropylene) separators achieve an excellent rate performance of up to 10C (∼358 mA h g⁻¹) and an outstanding long-term cycling stability with a high discharge capacity of 610 mA h g⁻¹ after 1000 cycles at 2C, corresponding to a pretty low capacity decay rate of 0.031% per cycle. Moreover, a high areal capacity of 5.51 mA h cm⁻² and satisfactory cycling stability can be realized under high sulfur loading (5.0 mg cm⁻²) and lean electrolyte (8 μL mg⁻¹) conditions.