Ultrathin MnO2 Sheet Arrays Grown on Hollow Carbon Fibers as Effective Polysulfide-Blocking Interlayers for High-Performance Li-S Batteries

Lithium-sulfur (Li-S) batteries are clean energy conversion devices with high theoretical energy densities and specific capacities. However, Li-S batteries exhibit poor cycling stability during the practical test, mainly because of the detrimental shuttle effect of intermediate lithium polysulfides (LiPSs). Here, we report a common and scalable strategy to prepare freestanding membranes of MnO2 sheet arrays anchored on natural cotton-derived hollow carbon fibers (MnO2/HCFs), which as interlayers can mitigate shuttling of LiPSs and thus boost the durabilities of Li-S batteries. By combining ultraviolet-visible absorption and X-ray photoelectron spectroscopy, we find that a MnO2/HCF interlayer can trap the LiPSs through chemical interactions between LiPSs and MnO2. With a MnO2/HCF interlayer, the Li-S battery shows a satisfactory capacity of 970 mA h g(-1) at 1 A g(-1) with a capacity decay of merely 0.12% per cycle over 500 cycles.