Core-sheath structured porous carbon nanofiber composite anode material derived from bacterial cellulose/polypyrrole as an anode for sodium-ion batteries

A core-sheath structured carbon nanofiber@nitrogen-doped porous carbon (CNF@NPC) composite is synthesized as a promising anode material for sodium-ion batteries (SIBs). Particularly, the eco-friendly bacterial cellulose (BC) is used as both template and precursor for the synthesis of CNF@NPC through the carbonization of bacterial cellulose@polypyrrole (BC@PPy). Due to the particular core-sheath structure and the synergetic effect between the CNF core layer and the NPC outer layer, the CNF@NPC exhibit outstanding electrochemical performance, including a high reversible specific capacity (240 mAh g−1 at 100 mA g−1 over 100 cycles), excellent rate performance (146.5 mAh g−1 at 1000 mA g−1), and superior cycling stability (148.8 mAh g−1 at 500 mA g−1 over 400 cycles). The application of environmentally friendly electrode material may open a new situation for SIBs.