Spherical Sulfur-Infiltrated\nCarbon Cathode with a\nTunable Poly(3,4-ethylenedioxythiophene) Layer for Lithium–Sulfur\nBatteries

Abstract

Li–S batteries have received significant attention\nowing\nto their high energy density, nontoxicity, low cost, and eco-friendliness.\nHowever, the dissolution of lithium polysulfide during the charge/discharge\nprocess and its extremely low electron conductivity hinder practical\napplications of Li–S batteries. Herein, we report a sulfur-infiltrated\ncarbon cathode material with a spherical morphology and conductive\npolymer coating. The material was produced via a facile polymerization\nprocess that forms a robust nanostructured layer and physically prevents\nthe dissolution of lithium polysulfide. The thin double layer composed\nof carbon and poly(3,4-ethylenedioxythiophene) provides sufficient\nspace for sulfur storage and effectively prevents the elution of polysulfide\nduring continuous cycling, thereby playing an essential role in increasing\nthe sulfur utilization rate and significantly improving the electrochemical\nperformance of the battery. Sulfur-infiltrated hollow carbon spheres\nwith a conductive polymer layer demonstrate a stable cycle life and\nreduced internal resistance. The as-fabricated battery demonstrated\nan excellent capacity of 970 mA h g^–1 at 0.5 C and\na stable cycle performance, exhibiting ∼78% of the initial\ndischarge capacity after 50 cycles. This study provides a promising\napproach to significantly improve the electrochemical performance\nof Li–S batteries and render them as valuable and safe energy\ndevices for large-scale energy storage systems.