MOF/MWCNT-coated Polyethylene Separator for Improving the Cycling Performance of the Lithium-Sulfur Cells

Abstract

Lithium-sulfur batteries have a higher theoretical energy density than those of conventional lithium-ion batteries and are therefore considered as one of the most promising candidates for future batteries. However, practical applications of lithium-sulfur batteries are still hindered by the dissolution of polysulfides from the sulfur cathode and their migration to the lithium anode through the separator. In this work, we demonstrate that a functionalized separator for lithium polysulfide trapping by coating Ni-MOF-74 (NOF) and multi-walled carbon nanotubes (MWCNT) on a polyethylene separator prevented the shuttle effect by effectively suppressing the polysulfides migration to the lithium anode. As a result, the lithium-sulfur cell assembled with functionalized separator exhibited high discharge capacity and enhanced cycling stability, with a reversible capacity of about 1200 mAh g-1 at 0.2 C after 300 cycles.