One-step synthesis of the CoO nanoarrays anchored on nickel foam as a three-dimensional current collector for lithium‑sulfur batteries

Practical application of lithium‑sulfur batteries (LSBs) is severely impeded by the poor conductivity of sulfur/Li₂S, large-volume change of active materials, shuttle effect and sluggish conversion reaction kinetics of polysulfides. To address these issues, a three-dimensional (3D) substrate, which was prepared by anchoring CoO nanoarrays on the surface of nickel foam (NF@CoO) through one-step hydrothermal treatment, is used as the current collector of the sulfur cathode. The as-prepared S/NF@CoO cathode presents excellent electrochemical performances due to the high electronic conductivity of nickel network, chemical adsorption and catalysis of CoO nanoarrays to LiPSs, and highly porous structure of nickel foam. The cathode with a sulfur loading of 2.72 mg cm⁻² can deliver an initial capacity of 490 mAh g⁻¹ at 1C, and 306 mAh g⁻¹ after 500 cycles. When the sulfur loading is increased to 5.12 mg cm⁻², the resultant cathode can achieve a capacity of 2.3 mAh cm⁻² at 0.5C. The results demonstrate that the 3D NF@CoO collector with synergistic effects of catalysis and chemisorption on LiPSs enable the sulfur cathode thick with meeting the requirements of practical use of LSBs.