A functional separator modified by synergistic MoS₂ and activated carbon for improved-performance lithium sulfur batteries

Abstract

Two kinds of different separator Li-S batteries were prepared. One separator was one-side coated with MoS2 towards anode, and the other separator was double-side coated with AC and MoS2 (AC-MoS2) towards cathode and anode respectively. These slurries of AC and MoS2 have the high specific surface area and porous structure, moreover, MoS2 has a highly 'catalyst' effect on sulfide conversion by virtue of its high electrochemical activity as well as strong binding energy with soluble lithium polysulfides. Assembled Li-S batteries with separators coated by AC-MoS2, MoS2 and uncoated separator show the initial discharged specific capacities of 1318 mAh g−1 and 1257 mAh g−1 and 957 mAh g−1 respectively, and those of 719 mAh g−1, 548 mAh g−1 and 306 mAh g−1 after 400 cycles at 0.2 C rate, with the coulombic efficiency remains over 98%. At the same time, the morphology of the separator coated by AC-MoS2 after 200 cycles exhibits a homogeneous sulfur distribution. This coating technology on the separator provides a facile and efficient route to obtain the superior Li-S battery.