Nitrogen-Rich Mesoporous Carbon as Anode Material for High-Performance Sodium-Ion Batteries

Nitrogen-rich carbon with interconnected mesoporous structure has been simply prepared via a nano-CaCO₃ template method, using polyaniline as carbon and nitrogen precursors. The preparation process includes in situ polymerization of aniline in a nano-CaCO₃ aqueous solution, carbonization of the composites and removal of the template with diluted hydrochloric acid. Nitrogen sorption shows the carbon-enriched mesopores with a specific surface area of 113 m² g^-1. The X-ray photoelectron spectroscopy (XPS) analysis indicates that the carbon has a high nitrogen content of 7.78 at.%, in the forms of pyridinic and pyrrolic, as well as graphitic nitrogen. The nitrogen-rich mesoporous carbon shows a high reversible capacity of 338 mAh g^-1 at a current density of 30 mA g^-1, and good rate performance as well as ultralong cycling durability (110.7 mAh g^-1 at a current density of 500 mA g^-1 over 800 cycles). The excellent sodium storage performance of the nitrogen-rich mesoporous carbon is attributed to its disordered structure with large interlayer distance, interconnected porosity, and the enriched nitrogen heteroatoms.