In situ growth of amorphous Fe₂O₃ on 3D interconnected nitrogen-doped carbon nanofibers as high-performance anode materials for sodium-ion batteries

In this work, a novel porous amorphous Fe₂O₃/nitrogen-doped carbon composite as a promising anode material for sodium-ion batteries has been fabricated by in situ growing amorphous Fe₂O₃ on 3D interconnected nitrogen-doped carbon nanofibers. The as-prepared composite exhibits superior sodium storage properties. It delivers a high reversible capacity of 408 mA h g⁻¹ after 350 cycles at a current density of 100 mA g⁻¹ and a good rate capability of 183 mA h g⁻¹ at 3 A g⁻¹. The excellent electrochemical performance is owing to the synergistic effects of the amorphous structure of Fe₂O₃ and the 3D interconnected nitrogen-doped carbon network with high nitrogen doping content (10 atom%), which do not only relieve the internal stress of the electrode and accommodate more electrochemical active sites for Na⁺ storage, but also buffer the volume changes of amorphous Fe₂O₃ as well as facilitate the electronic and ionic transportation during cycling.