三维石墨烯电极材料在锂离子电池中的应用

Application of Three-dimensional Graphene Electrode Material in Lithium Ion Battery

在二氧化硅微球衬底上,采用化学气相沉积(chemical vapor deposition,CVD)法生长石墨烯,经过浓硝酸在60℃处理8 h获得三维石墨烯材料,利用扫描电镜(scanning electron microscopy,SEM)、X射线衍射(X-ray diffraction,XRD)、X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)等设备测试三维石墨烯材料的微观结构与形貌,通过恒流充放电等电化学测试方法对三维石墨烯材料进行锂离子电池电化学性能研究。结果表明,通过CVD法构筑的三维石墨烯材料是一种自支撑多孔结构,经过浓硝酸处理后三维石墨烯微观形貌不发生改变,石墨烯表面含有一定量的含氧官能团,含氧量达到4.8 wt.%,将其作为锂离子电池负极材料,在50 m A/g电流密度下,首次充放电比容量达到516 m Ah/g,可逆容量达到267 m Ah/g。在电流密度为1 A/g条件下,经100次充放电循环后其放电比容量保持114 m Ah/g,显示出优异的倍率性能和循环稳定性。

Graphene is grown on silica microball substrate by chemical vapor deposition （CVD） method, and through concentrated nitric acid treatment at 60℃ for 8 hours, a three-dimensional graphene material is obtained. The microstructure and morphology of three-dimensional graphene material are measured by using scanning electron microscopy （SEM）, X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and other test equipments. The electrochemical performance of three-dimensional graphene material as an anode material in Li-ion battery is studied through electrochemical test methods such as constant current charge-discharge, etc. The results show that the three-dimensional graphene material constructed by CVD is a self-supporting porous structure, and after concentrated nitric acid treatment, the micro-morphology of three-dimensional graphene does not change. The surface of graphene has a certain amount of oxygen-containing functional groups, and the amount of oxygen reaches up to 4.8 wt.%. It is used as an anode material in lithium ion battery at a current density of 50 mA/g, the first charge-discharge specific capacity is 516 mAh/g, and the reversible capacity is about 267 mAh/g. At a current density of 1 A/g, the discharge specific capacity remains 114 mAh/g after 100 charge-discharge cycles, which exhibits excellent rate performance and cycle stability.