Nitrogen-doped hollow porous carbon nanotubes for high-sulfur loading Li–S batteries

Lithium-sulfur (Li–S) batteries have attracted extensive attention in the past decades owing to their high theoretical energy density, low-cost and eco-friendliness. However, poorly cycling stability and rapidly decay caused by shuttle effects at high-sulfur loading condition restrain their practical applications. Focusing on these issues, N-doped hollow porous carbon nanotubes (N-HPCNT) as a self-supporting sulfur cathode is developed. The inherent conductivity and abundant pores of 3D continuous framework not only allow a high-sulfur content (67 wt%) and block the polysulfides via physical confinement, but also trap the polysulfides by the nitrogen heteroatoms (4.60 wt%) via strong chemisorption . Benefiting from the above-mentioned merits, the self-supporting S/N-HPCNT cathode with 3 mg cm −2 sulfur delivers high reversible capacity, super rate capability (1152 and 852.8 mAh g −1 at 0.2 and 3 C, respectively) and long cycling stability (717.9 mAh g −1 after 500 cycles at 1 C). Even under a higher sulfur loading (8 mg cm −2 ), it still exhibits a stable areal capacity of 7.72 mAh cm −2 (corresponding to 965.1 mAh g −1 ) after 60 cycles. This work provides a pathway for developing high performance Li–S batteries.