Nb2O5-Decorated Nitrogen-Doped Carbon Nanotube Microspheres for Highly Efficient Sulfur Confinement in Lithium–Sulfur Batteries

To confine the intermediate polysulfides to obstruct their dissolution from the electrolyte and increase the utilization of sulfur, a novel sulfur host for decorated nitrogen-doped carbon nanotube (NCNTs) microspheres was produced by a terse ultrasonic spraying with succedent impregnation methods. Decoration effects for Nb2O5 are better than those for Sb. Nb2O5–NCNTs microspheres are woolen-like uniform balls which are twined with CNTs and infiltrated Nb2O5 nanoparticles. Then Nb2O5–NCNTs microspheres deliver the high initial charge and discharge capacities of 1369.5 and 1335.3 mAh g–1, good cycle stability of 1201.7 mAh g–1 at 0.1 C after 200 cycles, and outstanding long-term cycle life of 846.2 mAh g–1 after 1000 cycles at 2.0 C with a very low capacity decay of 0.016% per cycle. The Nb2O5–NCNTs microspheres with remarkable effects for sulfur confinement are a potential cathode material for lithium–sulfur batteries.