Efficient separators with fast Li-ion transfer and high polysulfide entrapment for superior lithium-sulfur batteries

A facile and general vacuum-filtration approach is employed to coat hierarchical metal-organic framework-derived Co-C polyhedrons onto traditional separators for lithium - sulfur batteries. The resultant condensed separators with Co-C coating (Co-C@separator) can effectively decrease the pore size of commercial separators from 200 to 300 nm to 2.2-10 nm. The decreased pore sizes block the shuttling of lithium polysulfides (LiPSs) through the separator, thus solving the annoying 'shuttle effect' via physical confinement. Furthermore, the embedded Co nano-nodes in Co-C polyhedrons are capable of capturing LiPSs via strong chemical adsorption of soluble LiPSs. Through this advantage combined with the rapid Li-ion transport through the intragranular pores between the Co-C polyhedrons, a sulfur-rich cathode (72% sulfur) has achieved outstanding performance when using the Co-C@separator, delivering decent cycling stability (675 mAh g(-1) after 300 cycles at 0.1 A g(-1)) and high rate performance (401 mAh g(-1) after 600 cycles at 1.0 A g(-1)). This approach serves as a facile strategy for remedying the shuttle phenomenon in lithium-sulfur batteries.

Automated summary

A vacuum-filtration approach is used to coat Co-C polyhedrons onto traditional separators for lithium-sulfur batteries, reducing pore size and blocking the shuttle effect of LiPSs. The Co-C@separator demonstrates excellent cycling stability and high rate performance, offering a facile strategy for improving lithium-sulfur battery performance.