氮掺杂石墨烯作为锂离子电池负极材料的电化学性能

Electrochemical performance of nitrogen-doped graphene as anode material for lithium ion batteries

以天然石墨为原料,通过氧化、快速热膨胀和超声分散制备石墨烯。将氧化石墨与三聚氰胺在氮气下950℃反应合成氮掺杂石墨烯。通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)以及红外光谱(FTIR)、X射线能谱(XPS)等测试方法对氮掺杂石墨烯的形貌、结构进行分析。结果表明,该方法合成了薄层状氮掺杂石墨烯。采用恒流充放电和循环伏安法等手段测试氮掺杂石墨烯、石墨烯和天然石墨作为锂离子电池负极材料的电化学性能,比较研究了三者用作锂离子电池负极材料的电化学性能,结果表明氮掺杂石墨烯负极材料具有优异的电化学能和独特的储锂机制。

Graphene sheets （GSs） have been prepared from natural flake graphite by oxidation, rapid expansion and ultrasonic treatment. Graphene oxide （GO） was further annealed at the presence of melamine at 950 ℃ and transferred into nitrogen-doped grapheme （N-GSs）. The samples were characterized via scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FT1R） and X-ray photoelectron spectroscopy （XPS）. Electrochemical performances of nitrogen-doped graphene, graphene and graphite as anode materials for lithium ion batteries were investigated using galvanostatic charge-discharge and cyclic voltammetry methods. It was found that the prepared N-GSs exhibited a relatively higher cycling stability and larger specific capacity compared with the pristine nature graphite and GSs. Cyclic voltammograms results indicate that the higher cycling stability may be associated with more structural defects during cycling.