N-Doped Carbon Nanonecklaces with Encapsulated Sb as a Sodium-Ion Battery Anode

The sodium-ion battery has shown great potential to replace the lithium-ion battery, especially for large-scale energy-storage systems. In this work, a hybrid material of ultra-small Sb nanoparticles encapsulated in unique N-doped carbon nanonecklace (Sb/N-CNN) has been synthesized for the first time via electrospinning and in situ substitution. As an anode material in sodium-ion batteries, the as-fabricated Sb/N-CNN exhibits superior rate property (314 mAh g −1 at 20 A g −1 ) and cycling stability (401 mAh g −1 after 6,000 cycles at 1 A g −1 ), outperforming other Sb-based materials. Such excellent performances originate from the ingenious necklace-like structure of Sb/N-CNN, which supplies efficient electrolyte diffusion paths and more active sites for Na + insertion/extraction, disperses the stress caused by the large volume change of Sb nanoparticles during the cycling process, and also reduces the electrode resistance. This study provides a facile strategy for construction of a well-designed structure for advanced energy-storage technologies.