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用天然鳞片石墨为原料,通过改进的Hummers法氧化、离心分离、热还原和超声剥离处理制备出了高品质的石墨烯片。采用透射电镜、高分辨透射电镜、傅里叶变换红外光谱、拉曼光谱、X-射线衍射等测试方法对石墨烯的结构和形貌进行了研究。通过恒流充放电、循环伏安法和交流阻抗等手段研究了石墨烯用作超级电容器电极材料的电化学性能,在0.02 A/g电流密度下的比容量为244 F/g。在0.1 A/g的电流密度下石墨烯超级电容器经过500个循环后比容量保持在198 F/g,表明石墨烯电极材料具有优异的循环稳定性。
Using natural flake graphite as raw material, high quality graphene sheets were prepared by improved Hummers method, centrifugal separation, thermal reduction and ultrasonic stripping treatment. The structure and morphology of graphene were investigated by transmission electron microscopy, high resolution transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and X-ray diffraction. The electrochemical performance of graphene as an electrode material for supercapacitors was investigated by means of constant current charge and discharge, cyclic voltammetry and AC impedance. The specific capacity of the graphene was 244 F / g at a current density of 0.02 A / g. The graphene supercapacitor maintains a specific capacity of 198 F / g after 500 cycles at a current density of 0.1 A / g, indicating that the graphene electrode material has excellent cycling stability.