Nitrogen doped hollow carbon nanospheres as efficient polysulfide restricted layer on commercial separators for high-performance lithium-sulfur batteries

The polysulfide shuttle limits the development of lithium-sulfur (Li-S) batteries with high energy density and long lifespan. Herein, nitrogen doped hollow carbon nanospheres (NHCS) derived from polymerization of dopamine on SiO 2 nanospheres are employed to modify the commercial polypropylene/polyethylene/polypropylene tri-layer separators (PP/PE/PP@NHCS). The abundant nitrogen heteroatoms in NHCS exhibit strong chemical adsorption toward polysulfides, which can effectively suppress the lithium polysulfides shuttle and further enhance the utilization of active sulfur. Lithium-sulfur batteries employing the PP/PE/PP@NHCS deliver an initial discharge capacity of 1355 mAh/g and retain high capacity of 921 mAh/g after 100 cycles at 0.2 C. At high rate of 2 C, the lithium-sulfur batteries exhibit capacity of 461 mAh/g after 1000 cycles with a capacity fading rate of 0.049% per cycle. This work demonstrates that the NHCS coated PP/PE/PP separator is promising for future commercial applications of lithium-sulfur batteries with improved electrochemical performances. Commercial polypropylene/polyethylene/polypropylene tri-layer separators modified by nitrogen doped hollow carbon nanospheres (PP/PE/PP@NHCS) exhibits efficient inhibition of lithium polysulfides shuttle due to the abundant nitrogen heteroatoms and unique hollow spherical morphology in NHCS, further promotes the utilization of active sulfur, and thus resulting in enhanced electrochemical performances of Li-S batteries.