Na^+插层与MWCNTs隔离对石墨烯结构调控及电容性能

Controlling of graphene structure via Na^+ intercalation and multiwalled carbon nanotube spacers with supercapacitor performance

利用水热法制备的还原氧化石墨烯(RGO)由于重新堆叠和团聚严重影响了其超级电容器性能.本文工作中,水热反应前在氧化石墨烯(GO)溶液中依次加入NaCl和多壁碳纳米管(MWCNTs),基于Na^+插层和MWCNTs隔离作用,可有效阻碍RGO片层的重新聚集,得到均一、分散的多级孔结构.对于RGO-Na-MWCNTs,其比表面积可达571.2 m^2·g^(-1),介孔和大孔比例也都得到了明显增加,这为电荷聚集和离子扩散提供了更多活性区域和扩散通道.纯离子液体系中(室温环境下),该优化的聚集结构使得RGO-Na-MWCNTs获得了较高的比容量245.6 F·g^(-1)(2 mV·s^(-1))以及优越的电化学性能.这种利用Na+插层和MWCNTs隔离的协同效应为制备可分散二维层状材料提供了实验基础,并促进了石墨烯基超级电容器的商业化应用.

The restacking of reduced graphene oxide（RGO） prepared via a hydrothermal method severely affected its supercapacitors performance.We developed a simple strategy from incorporating Na Cl and multiwalled carbon nanotubes（MWCNTs） in turn to graphene oxide solution.With synergistic effect of Na~＋ ions intercalation and MWCNTs spacers,the restacking of RGO sheets can be restrained with a uniformly dispersed hierarchical pore structure.For RGO-Na-MWCNTs,a high specific surface area（571.2 m^2·g^-1） with enhanced fractions of mesopores and macropores can provide more reactive areas and pathways for charge accommodation and ions diffusion.The optimized hierarchical pore structure achieve a high specific capacity of 245.6 F·g^（-1）（at 2 mV·s^（-1）） and superior electrochemical performance in pure ionic liquid electrolyte at room temperature.The synergistic effect of Na~＋ ions intercalation and MWCNTs spacers can offer experimental basis for preparing dispersed two-dimensional layered materials,which can also promote the commercial application of graphene-based supercapacitors.