Preparation And Electrochemical Performance Of Three Dimensional Graphene And Its Composites

In this paper,the experiments were synthesized by the simple hydrothermal method.Three dimensional graphene hydrogel was successfully synthesized by hydrothermal method;Preparation of graphene hydrogel loaded silver nanoparticles(Ag/GH)by hydrothermal method;Nitrogen-doped graphene hydrogel was prepared by low-temperature hydrothermal method.The structure and morphology of graphene hydrogel and composites were characterized by transmission electron microscopy(TEM),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),field emission scanning electron microscopy(FESEM)and Raman spectroscopy.At the same time,we used electrochemical workstation to carry out cyclic voltammetry(CV),galvanostatic charge discharge and AC impedance test to explore the electrochemical properties of the materials.The specific experiment can be divided into three parts:1.Graphene hydrogel were synthesized by one-step hydrothermal method at low temperature and used as the electrode material of the supercapacitor.Graphene hydrogel have unique three-dimensional porous network structure and large specific surface area,which can improve the diffusion capacity and electronic transport capacity of the ions in the electrolyte,showing excellent electrochemical performance in electrochemical tests.2.Graphene hydrogel loaded silver nanoparticles composite was prepared by one-step hydrothermal method.The three-dimensional porous structure and large specific surface area of the graphene hydrogel can provide more active sites for the silver nanoparticles,silver nanoparticles can increase the conductivity and improve the ability of electron transfer of graphene hydrogel,combined with each other to greatly improve the catalytic ability.3.Different nitrogen doped graphene hydrogels were synthesized by hydrothermal method and the electrochemical properties of the hydrogels were studied.The doping of nitrogen atoms increases the surface area and improves the conductivity of graphene.Meanwhile,the doping of nitrogen atoms provides pseudopotential capacitance,which improves the electrochemical performance.At a current density of 1 Ag-1,the specific capacitance of the nitrogen-doped graphene hydrogel is 500 Fg-1,showing good capacitance characteristics.