A N/S-codoped disordered carbon with enlarged interlayer distance derived from cirsium setosum as high-performance anode for sodium ion batteries

Biomass is considered an appropriate source for carbon anodes. In this paper, N/S-codoped carbon (NSC) was synthesized through hydrothermal pretreatment and subsequent melamine/sulfur activation with the cirsium setosum precursor. After being tested as anode material of sodium ion battery, the N/S-codoped carbon shows a reversible capacity of 268 mA h g −1 at the current density of 100 mA g −1 after 100 cycles. Moreover, it exhibits a long life and high rate performance (198.6 mAh g −1 at 1000 mA g −1 after 320 cycles and 133.9 mA h g −1 at 5000 m A g −1 after 1000 cycles). The superior electrochemical performance of NSC can be ascribed to its larger interplanar spacing (0.394 nm) and the increase in disordered degree due to the nitrogen/sulfur-codoped.