Ultrathin MnO<sub>2</sub> Sheet Arrays Grown on Hollow Carbon Fibers as Effective Polysulfide-Blocking Interlayers for High-Performance Li–S Batteries
Guojie Chao, Longsheng Zhang, Shijia Yuan, Tiantian Xue, Fan Yang, Yunpeng Huang, Wei Fan, Tianxi Liu
Abstract
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.