Core-shell-structured hollow carbon nanofiber@nitrogen-doped porous carbon composite materials as anodes for advanced sodium-ion batteries

Core-shell-structured hollow carbon nanofiber@nitrogen-doped porous carbon (HCNF@NPC) composite materials were prepared by carbonization of HCNF@polyaniline. The HCNF@NPC composite materials are applied to the anode for sodium-ion batteries, showing a superior reversible discharge capacity of 182 mAh g(-1) after 200 cycles at 50 mA g(-1). Moreover, excellent long-term cycling stability (> 2500 cycles) is also obtained even at 500 mA g(-1). The results indicate that the HCNF@NPC composite electrode shows outstanding electrochemical performance. The excellent performance of HCNF@NPC composite electrode may attribute to the synergetic effect between HCNF core and NPC shell layer, and the HCNF core can provide a firm hollow carbon matrix to stabilize the electrode structure, and the NPC shell layer can improve the capacity effectively.