Free‐Standing Nitrogen‐Doped Carbon Nanofiber Films: Integrated Electrodes for Sodium‐Ion Batteries with Ultralong Cycle Life and Superior Rate Capability

The fabrication of large-area free-standing porous nitrogen-doped carbon nanofiber films is reported. The flexible film exhibits a high rate capability and ultralong cycle life used for sodium-ion batteries, due to the presence of abundant pores, high nitrogen-doping level, interconnected conductive network, and excellent structural stability of the electrode.