摘要：

Graphene has been widely studied and applied in the electrode materials of supercapacitors due to its good electrical stability and high theoretical capacitance. In this study, graphene oxide (GO) is prepared by a modified Hummer's method and then reduced to obtain reduced graphene oxide (rGO). However, due to the incomplete reduction, the existence of oxygen-containing groups or defects on graphene layers may lead to poor electrical conductivity. Meanwhile, for thermodynamic stability, the graphene layers tend to agglomerate when kept for long time, resulting in the degradation of electrochemical properties. Multi-walled carbon nanotubes (MWCNTs) are one-dimensional materials with high aspect ratio and high electrical conductivity. Nevertheless, due to their insufficient hydrophilicity, their electrochemical properties such as capacitance are limited, which hinders their further development in supercapacitors. In this work, rGO/MWCNTs composite was synthesized without any surfactants and analyzed by means of structural and electrochemical tests. The variations on microstructure, surface chemical states, defects, and electrochemical properties of rGO/MWCNTs composite at different preservation times were investigated, which were also compared with those of the pure rGO under the same preservation conditions. The results show that, for long-time preservation, the addition of MWCNTs can inhibit the agglomeration of rGO and improve the rate capability and cyclic stability as the electrode material of supercapacitor. This study is of great guiding significance for understanding the time failure of rGO and rGO/MWCNTs composite in practical applications.

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