Nanomaterials Based On Graphene Application In Electrochemical Supercapacitor

As a new energy storage device, electrochemical supercapacitor has attract much attention of researchers. However, the electrode material is a direct impact on the performance of the supercapacitor, so the focus of the study is concentrated to high conductivity and good reversibility of electrode material. As a new carbon material wiith unique structure, graphene has good electrical conductivity, large specific surface area and other unique advantages. Therefore, graphene has widely application prospect in supercapacitor. But the aggregation of graphene layers can lead to the decrease of surface area, Which decease the performance of electric double layer capacitance of supercapacitor. Metal oxides/hydroxides and polymer have high pseudo-capacitance, when graphene interact with them, metal oxides/hydroxides or polymer can effectively prevent the aggregation of graphene layer, thereby enlarging the specific surface area of graphene. At the same time, graphene can improve the conductivity of metal oxides/hydroxides and polymer. This will enhance the capacitance of the system,including the electric double layer capacitance and pseudo-capacitance. In the paper, we study the supercapacitor electrode material with high performance. Then we prepare the electrode materials such as graphene/POM/meso-carbon sphere nanocomposite, polyaniline nano-fiber, graphene/polyaniline nanocomposites and graphene/polyaniline/carbon quantum dots composite. In this paper, we characterize the structure, test their performance, and analyzes the difference between these materials. The main contents are shown as following:(1) self-assembly of Graphene/POM/Meso-Carbon sphere nanocomposite for application in supercapacitor.In the chapter,we combine graphene(GN),POM and mesoporous carbon sphere (CS) together to form GN/POM/CS nanocomposites. Through the SEM, FITR and XPS method,we analyze the structure and morphologies of them. We test the electrochemical performance of them by three electrode system in 0.5mol/L H2SO4 electrolyte solution.The result show that the specific capacitance of the GN/POM/CS composites reached 430F/g at the current density of 1A/g, indicating the complex has good electrochemical performance.(2) layer-by-layer assembly Graphene/PANI/Carbon quantum dots compostie for apllication in electrochemical supercapacitor.In the chapter, we innovatively introduce the carbon quantum dots into supercapacitor. Carbon quantum dots is mainly used in biosensors, medicine and LED. And we combine the grapheme((GN), polyaniline(PANI) and carbon quantum dots(C-dots) together to form GN/PANI/C-dots composites. Firstly, The structure and morphology of the complex are characterized by SEM, TEM and FI-TR. Following, We test the electrochemical performance of them by three electrode system in 0.5mol/L H2SO4 electrolyte solution. The result displayed that the specific capacitance of the GN/PANI/C-dots composites achieved 477F/g at the current density of 1A/g. And after 760 charge/discharge cycles, specific capacity retention rate reached 81%, indicating that the composite material has good cycle stability and capacitance performance.