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以石墨(G)和碳纳米管(MWCNTs)为原料,通过共同化学氧化-热还原的简便途径,制备了石墨烯/碳纳米管复合材料(RGO/RCNTO)。为便于比较,采用同样方法分别获得了热还原后的石墨烯(RGO)和碳纳米管(RCNTO)。用扫描电镜(SEM)、透射电镜(TEM)、红外光谱(FTIR)、X射线衍射(XRD)对材料进行结构和形貌表征。研究发现:由于氧化石墨(GO)和氧化碳纳米管(CNTO)存在一定的含氧官能团,形成均匀的氧化石墨/氧化碳纳米管复合物(GO/CNTO)。紧接着的热解过程又使得GO层因层间产生的气体膨胀而剥离,RCNTO随之进入层间,还原后石墨烯由于π—π作用吸引,重新堆积并将RCNTO裹在层间形成了三明治结构的RGO/RCNTO。复合材料在电流密度1 A·g~(-1)时的比电容为422.4 F·g~(-1),经过5 000次恒流充放电比电容仍保持在90%以上。良好的电容特性如高比容量和稳定的循环性能归因于该复合材料中RGO和RCNTO有效的协同作用。
The graphene / carbon nanotube composites (RGO / RCNTO) were prepared by the common chemical oxidation-thermal reduction method using graphite (G) and carbon nanotubes (MWCNTs) as raw materials. For comparison, graphene (RGO) and carbon nanotube (RCNTO) were obtained by the same method. The structure and morphology of the material were characterized by SEM, TEM, FTIR and XRD. It is found that a uniform graphite oxide / carbon nanotube composite (GO / CNTO) is formed due to the existence of certain oxygen-containing functional groups in GO and CNTO. The subsequent pyrolysis process causes the GO layer to peel off due to the expansion of the gas generated in the interlayer. As a result, the RCNTO enters the interlayer. After the reduction, the graphene is attracted by the π-π interaction, and then the RCNTO is sandwiched to form a sandwich Structure of the RGO / RCNTO. The specific capacitance of the composites at the current density of 1 A · g ~ (-1) was 422.4 F · g ~ (-1), and the specific capacitance of the composite remained above 90% after 5 000 cycles of constant current charge-discharge. Good capacitance characteristics such as high specific capacity and stable cycling performance are due to the synergistic effect of RGO and RCNTO in the composite.