Liu Jinlong, Zhang Yaqian, Zhang Lei, Xie Fangxi, Vasileff Anthony, Qiao Shi-Zhang
School of Chemical Engineering, The University of Adelaide, Adelaide, SA, 5005, Australia.
Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada.
Adv Mater. 2019 Jun;31(24):e1901261. doi: 10.1002/adma.201901261. Epub 2019 Apr 18.
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-C N ) 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 at 40 A g ) and excellent long-term stability (211.3 mAh g at 0.5 A g after 2000 cycles), demonstrating the effectiveness of material design.
具有扩大层间距的杂原子掺杂碳材料作为钠离子电池（SIBs）的负极已被广泛研究。然而，为了开发更高效的SIB负极材料，进一步扩大层间距并揭示杂原子掺杂对碳纳米结构的影响仍有待探索。在此，通过在锌催化和选定温度（T = 700、800和900°C）下对石墨相氮化碳（g-CN）进行退火，成功合成了一系列层间距可调、范围为0.45至0.51 nm的富氮少层石墨烯（N-FLG）。更重要的是，所得N-FLG-T中N掺杂剂与层间距之间的相关性突出了吡咯氮对石墨烯层间距扩大的影响，这是由于其较强的静电排斥作用。因此，N-FLG-800在层间距、氮构型和电子导电性方面达到了最佳性能。当用作SIBs的负极时，N-FLG-800表现出卓越的钠存储性能，具有超高倍率性能（在40 A g下为56.6 mAh g）和出色的长期稳定性（在0.5 A g下循环2000次后为211.3 mAh g），证明了材料设计的有效性。
