Hierarchical cobalt sulfide ultra-long microtube composed of nanosheets embedded within N-doped carbon as anode material for lithium-ion batteries

An effective and scalable strategy was used to develop cobalt sulfide microtubes composed of nanosheets coated with an N-doped carbon shell (Co₉S₈@N-C) as an anode material for Li-ion batteries. The conductive carbon shell can provide fast transport of ions and electrons within the electrode, while remarkably enhancing the structural integrity of the electrode. Moreover, the volume expansion and aggregation of Co₉S₈ can be inhibited during lithiation-delithiation due to the intimate contact between Co₉S₈ and the carbon shell. Benefiting from this structure, the Co₉S₈@N-C manifested outstanding electrochemical performance including an initial specific capacity of 1654 mAh g⁻¹ higher than that of Co₉S₈ (1350 mAh g⁻¹) at a current density of 100 mA g⁻¹, excellent rate capability, and superior cycling stability at 500 mAh g⁻¹ for 2000 cycles. This electrochemical performance can be attributed to its superior conductivity, robust nanostructure, and relatively large surface area, rendering it a promising candidate for use as an anode material in Li-ion batteries.