Rational design of a cobalt sulfide nanoparticle-embedded flexible carbon nanofiber membrane electrocatalyst for advanced lithium–sulfur batteries

Abstract

Both the sluggish redox kinetics and severe polysulfide shuttling behavior hinders the commercialization of lithium–sulfur (Li–S) battery. To solve these obstacles, we design a cobalt sulfide nanoparticle-embedded flexible carbon nanofiber membrane (denoted as CoS2@NCF) as sulfiphilic functional interlayer materials. The hierarchically porous structure of carbon nanofiber is conducive to immobilizing sulfur species and facilitating lithium-ion penetration. Moreover, electrocatalytic CoS2 nanoparticles can significantly enhance the catalytic effect, achieving favorable adsorption-diffusion-conversion interface of polysulfide. Combined with these synergistic features, the assembled Li–S cell with CoS2@NCF interlayer exhibited a great discharge capacity of 950.9 mAh g−1 with prolonged cycle lifespan at 1 C (maintained 648.1 mAh g−1 over 500 cycles). This multifunctional interlayer material used in this contribution provides an advanced route for developing high-energy-density Li–S battery.