Nb₂O₅‑Decorated Nitrogen-Doped\nCarbon Nanotube Microspheres for Highly Efficient Sulfur Confinement\nin Lithium–Sulfur Batteries

Abstract

To\nconfine the intermediate polysulfides to obstruct their dissolution\nfrom the electrolyte and increase the utilization of sulfur, a novel\nsulfur host for decorated nitrogen-doped carbon nanotube (NCNTs) microspheres\nwas produced by a terse ultrasonic spraying with succedent impregnation\nmethods. Decoration effects for Nb₂O₅ are better\nthan those for Sb. Nb₂O₅–NCNTs microspheres\nare woolen-like uniform balls which are twined with CNTs and infiltrated\nNb₂O₅ nanoparticles. Then Nb₂O₅–NCNTs microspheres deliver the high initial charge\nand discharge capacities of 1369.5 and 1335.3 mAh g^–1, good cycle stability of 1201.7 mAh g^–1 at 0.1\nC after 200 cycles, and outstanding long-term cycle life of 846.2\nmAh g^–1 after 1000 cycles at 2.0 C with a very low\ncapacity decay of 0.016% per cycle. The Nb₂O₅–NCNTs microspheres with remarkable effects for sulfur confinement\nare a potential cathode material for lithium–sulfur batteries.