Functionalized N-doped interconnected carbon nanofibers as an anode material for sodium-ion storage with excellent performance

The electrochemical performance of sodium-ion battery was improved by using functionalized interconnected N-doped carbon nanofibers (FN-CNFs) as the anode. The material was synthesized with polypyrrole as precursor by a simple method. The FN-CNF electrode exhibits excellent rate capability and cycling stability, delivering a capacity of 134.2 mAh g−1 at a high current density of 200 mA g−1 after 200 cycles and retains a capacity of 73 mAh g−1 even at an extremely high current density of 20 A g−1. The superior performance can be attributed to N-doped sites and functionalized groups, which are capable of capturing sodium ions rapidly and reversibly through surface adsorption and surface redox reactions.