A 3D MoS2/Graphene Microsphere Coated Separator for Excellent Performance Li-S Batteries

Lithium-sulfur (Li-S) batteries are the most prospective energy storage devices. Nevertheless, the poor conductivity of sulfur and the shuttling phenomenon of polysulfides hinder its application. In this paper, flower-like MoS2/graphene nanocomposite is prepared and deposited on a multi-functional separator to enhance the electrochemical behavior of Li-S batteries. The results demonstrated that the MoS2/graphene-coated separator is contributing to inhibit the shuttling phenomenon of polysulfides and improve the integrity of sulfur electrode. The initial discharge capacity of the battery using MoS2/graphene-coated separator at 0.2 C was up to 1516 mAh g−1. After 100 cycles, a reversible capacity of 880 mAh g−1 and a coulombic efficiency of 98.7% were obtained. The improved electrochemical behavior can be due to the nanostructure and Mo-S bond of the MoS2/graphene composite, which can combine physical shielding and chemisorption to prohibit the shuttle effect of polysulfides. The results prove that the MoS2/graphene-coated separator has the potential for feasible application in Li-S batteries to enhance their electrochemical performance.