Metal-organic framework/carbon nanotube-coated polyethylene separator for improving the cycling performance of lithium-sulfur cells

Abstract

Since the so-called 'shuttle effect' is the key obstacle for the practical development of lithium-sulfur batteries, the present attempt is to make the separator less permeable for polysulfides. For this purpose, we synthesized Ni-based metal-organic framework (Ni-MOF) particles and coated them with multi-walled carbon nanotubes (MWCNTs) onto the polyethylene (PE) separator. The Ni-MOF particles on separator effectively blocked the migration of lithium polysulfides toward the anode side owing to the strong interaction between Ni-MOFs and lithium polysulfides. The highly conductive MWCNTs in the coating layer allowed reutilization of the trapped reaction intermediates during the subsequent cycles. Due to these beneficial effects of coating materials, the lithium-sulfur cell assembled with Ni-MOF/ MWCNT-coated PE separator initially delivered a high discharge capacity of 1358 mAh g(-1) with good cycling stability and high-rate performance.