Graphitic Carbon Nitride (g‐C3N4)‐Derived N‐Rich Graphene with Tuneable Interlayer Distance as a High‐Rate Anode for Sodium‐Ion Batteries

• Published in: Advanced materials (Weinheim) 2019-06, Vol.31 (24), p.e1901261-n/a
• Main Authors: Liu, Jinlong, Zhang, Yaqian, Zhang, Lei, Xie, Fangxi, Vasileff, Anthony, Qiao, Shi‐Zhang
• Format: Article
• Language: English
• Subjects: Anodes; Carbon; Carbon nitride; Catalysis; Electrode materials; Enlargement; few‐layer graphene; Graphene; graphitic carbon nitride; interlayer distance; Interlayers; Materials science; Nitrogen; nitrogen doping; Rechargeable batteries; Sodium-ion batteries
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201901261

Heteroatom‐doped carbon materials with expanded interlayer distance have been widely studied as anodes for sodium‐ion batteries (SIBs). However, it remains unexplored to further enlarge the interlayer spacing and reveal the influence of heteroatom doping on carbon nanostructures for developing more efficient SIB anode materials. Here, a series of N‐rich few‐layer graphene (N‐FLG) with tuneable interlayer distance ranging from 0.45 to 0.51 nm is successfully synthesized by annealing graphitic carbon nitride (g‐C3N4) under zinc catalysis and selected temperature (T = 700, 800, and 900 °C). More significantly, the correlation between N dopants and interlayer distance of resultant N‐FLG‐T highlights the effect of pyrrolic N on the enlargement of graphene interlayer spacing, due to its stronger electrostatic repulsion. As a consequence, N‐FLG‐800 achieves the optimal properties in terms of interlayer spacing, nitrogen configuration and electronic conductivity. When used as an anode for SIBs, N‐FLG‐800 shows remarkable Na+ storage performance with ultrahigh rate capability (56.6 mAh g−1 at 40 A g−1) and excellent long‐term stability (211.3 mAh g−1 at 0.5 A g−1 after 2000 cycles), demonstrating the effectiveness of material design. Well‐controlled N‐doped few‐layer graphene (N‐FLG) with tunable interlayer structure, nitrogen content, and nitrogen configuration, is realized through the pyrolysis of g‐C3N4 under zinc catalysis and appropriate temperature. The optimal N‐FLG‐800 features significantly enlarged interplanar spacing and high nitrogen content with pyridinic and pyrrolic configurations, resulting in superior Na+ storage performance and ultrahigh rate capability.