To inhibit the polysulfide-diffusion in lithium sulfur (Li-S) batteries and improve the electrochemical properties, the commercial polypropylene (PP) was decorated by an active carbon (AC) coating with lots of electronegative oxygenic functional group of -OH. Owing to the strong adsorption of AC and the electrostatic repulsion between the -OH and negatively charged polysulfide ions, the Li-S batteries demonstrated a high initial discharge capacity of 1,656 mAh g-1 (approximately 99% utilization of sulfur) and the capacity can still remain at 830 mAh g-1 after 100 cycles at 0.2 C. Moreover, when the rate was increased to 1 C, the batteries could also possess a discharge capacity of 1,143 mAh g-1. The encouraging cycling stability make clear that this facile approach can successfully restrain the shuttle effect of polysulfides and make further progress to the practical application of Li-S batteries.
Keywords: active carbon; isopropyl alcohol; lithium-sulfur battery; polysulfide adsorption; separator.