Novel “Bird-Nest” Structured Co₃O₄/Acidified Multiwall Carbon Nanotube (ACNT) Hosting Materials for Lithium–Sulfur Batteries

Lithium–sulfur battery with a much higher specific capacity and energy density than the commercial Li-ion battery is the most promising energy storage system. However, the shuttle effect of the dissolved sulfide polyanions and the insulating sulfur materials during charge/discharge of Li–S batteries reduce the coulombic efficiency and the cycle life of the batteries. Herein, we prepared novel Co3O4/acidified multiwall carbon nanotube (ACNT) hosting materials with a stable “bird-nest” structure, which integrates metal oxide with a conductive framework effectively. The double barrier of the “bird-nest” hosting materials suppress the shuttle effect and the carbon nanotubes provide a high electronic conductivity in the sulfur cathode. The composite Co3O4/S/ACNT cathode exhibited an initial discharge capacity of 1285 mAh g–1 at 0.1 C and 693.7 mAh g–1 was retained after 550 cycles at 0.5 C. The cross-linked “bird-nest” structure not only encapsulates polysulfide effectively, but also promotes the transformation and utilization of polysulfides thanks to the catalytic properties of Co3O4.