Multifunctional Interlayer Based on Molybdenum Diphosphide Catalyst and Carbon Nanotube Film for Lithium–Sulfur Batteries

Abstract

A multifunctional interlayer, composed of molybdenum diphosphide (MoP₂ ) nanoparticles and a carbon nanotube (CNT) film, is introduced into a lithium-sulfur (Li-S) battery system to suppress polysulfide migration. Molybdenum diphosphide acts as the catalyst and can capture polysulfides and improve the polysulfide conversion activity during the discharge/charge processes. The CNT film acts as a conductive skeleton to support the MoP₂ nanoparticles and to ensure their uniform distribution. The CNT film physically hinders polysulfide migration, acts as a current collector, and provides abundant electron pathways. The Li-S battery containing the multifunctional MoP₂ /CNT interlayer exhibits excellent electrochemical performance. It delivers a reversible specific capacity of 905 mA h g^-1 over 100 cycles at 0.2 C, with a capacity decay of 0.152% per cycle. These results suggest the introduction of the multifunctional CNT/MoP₂ interlayer as an effective and practical method for producing high-performance Li-S batteries.