Synthesis of nitrogen-containing hollow carbon microspheres by a modified template method as anodes for advanced sodium-ion batteries

Nitrogen-containing hollow carbon microspheres (NHCSs) are prepared by a modified template method in the presence of resorcinol/formaldehyde as carbon precursors and ethylenediamine (EDA) as both a base catalyst and nitrogen precursor. The NHCSs are used as anode materials for sodium-ion batteries, showing a superior reversible discharge capacity of 334 mAh g−1 after 100 cycles at 50 mA g−1. A high reversible discharge capacity of 114 mAh g−1 can also be obtained even at an extremely high current density of 10 A g−1. Moreover, excellent long-term cycling stability (>1200 cycles) is also observed even at 500 mA g−1. The results show that the NHCS electrode exhibits excellent electrochemical performance (superior reversible capacity, high rate capability, and long-term cycling stability). The excellent performance of NHCS electrode is most likely attributed to the unique nitrogen-containing hollow carbon structure. Furthermore, this study provides a novel route to produce NHCSs, which may find application in other fields.