Preparation And Electrochemical Properties Of Graphene/Carbon Nanotube Arrays

In this paper,multilayer graphene/carbon nanotube arrays were grown on the surface of metal Cu by chemical vapor deposition?CVD?.The prepared samples were heat-treated and combined with metal oxides to improve the electrochemical performance of the materials.The morphology and microstructure of the material were characterized by SEM,TEM,Raman spectroscopy and XPS technology.Electrochemical performance of the material was tested by electrochemical workstation.The main research contents are as follows:1.Multilayered graphene films were grown on the surface of metal copper by chemical vapor deposition,and carbon nanotube arrays were grown on the surface of graphene as a transition layer to form graphene/carbon nanotube hybrid structures.The results show that the carbon nanotube is a multi walled structure with a diameter of about 9 nm,with complete structure and few defects.2.Graphene/carbon nanotube arrays were heat-treated in argon and air atmosphere,and their structure and electrochemical properties were characterized.The results showed that the carbon nanotube bundles were fractured and the dispersibility increased after heat treatment.Due to the rearrangement of carbon atoms and clean oxidation,the graphitization degree of carbon nanotubes increased and the defects decreased.The electrochemical test showed that under 1 A/g current density,the specific capacitance of samples treated in air atmosphere was97.7 F/g,which was 2.3 times as high as that of untreated samples,and the ratio of capacitance kept up to 91.9%at 20 A/g current density.3.Graphene/carbon nanotubes/manganese dioxide,graphene/carbon nanotubes/ferric oxide,graphene/carbon nanotubes/nickel oxide,graphene/carbon nanotubes/four oxidation three cobalt composites were prepared by thermal decomposition of acetacetone salts,and their structure and electrochemical properties were characterized.The results show that the size of nano metal oxide Me_xO_y is about a few nanometers to tens of nanometers,and is evenly distributed on the surface of carbon nanotubes.After loading metal oxide,the degree of graphitization of carbon nanotubes increased,but the defects increased significantly.Electrochemical tests showed that the electrochemical properties of G/CNTs-Me_xO_y composite structures were significantly enhanced,in which the specific capacitance of G/CNTs-MnO₂ composites reached 365 F/g at 1 A/g current density,and the specific capacitance retention rate was 92%after 1000 cycles.