Nitrogen-enriched Carbon Nanofibers with Tunable Semi-ionic C-F bonds as a Stable Long cycle Anode for Sodium-Ion Batteries

Abstract The quest for getting more efficient carbonous anodes for sodium ion batteries (NIBs) prepared by simple and economical methods continues to be an important endeavor. Herein, a plasma-controlled method is developed for preparing semi-ionic C-F bonds decorating nitrogen-enriched electrospinning carbon nanofibers (NCNFs) as a free-standing anode for NIBs. The semi-ionic C-F bonds are beneficial to the fast ion and electron transfer for a free-standing electrode, which remarkably improves the rate performances of NCNFs as the NIBs anodes. The optimized sample delivers a reversible capacity of 199 mA h g-1 at 0.1 A g−1 and displays excellent long-term stability with reversible specific capacity around 150 mA h g-1 over 2000 cycles at 500 mA g-1 after the rate capability test. Moreover, the presence of semi-ionic C-F bonds on plasma nitrogen-enriched electrospinning carbon nanofibers surfaces can reduce the resistance of the anode, thereby showing a more stable solid electrolyte interphase SEI) after electrochemical cycles.