Synthesis And Electrochemical Properties Of Three-dimensional Graphene And Its Composites

In this paper, three-dimensional graphene was obtained by solution method. And raw material is p-phenylenediamine hydrochloride(PPDHCl) modified graphene oxide. And then composite electrode material obtained by compounding three-dimensional graphene and Ni(OH)2. Morphologies would be analysed by scanning electron microscopy(SEM) surface analysis technologies. Electrochemical properties are tested. The work of this paper are as follows:A series of RGO-PPDHCl electrode materials are obtained by using different amounts of PPDHCl modified graphene oxide. The results of scanning electron microscopy analysis show that graphene has a three-dimensional structure by using PPDHCl modified, and graphene which do not use PPDHCl modified exist more serious aggregation. The analysis of SEM indicate that using PPDHCl modified graphene oxide can effectively improve the morphology of graphene. With 1 M H2SO4 as the electrolyte, at the current density of 2 A/g, the specific capacitance are calculate by discharge curve, the specific capacitance of RGO-PPDHCl-2 is 256 F/g. at the current density of 200 A/g, the specific capacitance of RGO-PPDHCl-2 is 136 F/g, with a poor rate capability.The graphene oxide possessing lower degree oxidation was obtained by reducing the graphene oxide during the oxidizing process of synthesis graphene oxide. After that the graphene oxide was modified by PPDHCl.It was found that RGO-PPDHCl has an open, three-dimensional structure of interconnected by SEM. With 1 M H2SO4 as the electrolyte, at the current density of 2 A/g, the specific capacitance of RGO-PPDHCl is 256F/g, the specific capacitance value of modified is higher than unmodified RGO-PPDHCl; At the current density of 200 A/g, the same results were obtained. The above results shows that the rate capability of modified RGO-PPDHCl is superior to unmodified RGO-PPDHCl. Charge and discharge 1000 times at the current density of 20 A/g, capacity retention rate is 98%. It shows a good cycle stability.Mixed synthesized three-dimensional graphene with different amount of Ni(NO3)2 ? 6H2 O rapidly. And then different loadings dimensional graphene- nickel hydroxide composite are prepared by washing and drying. With 6 M KOH as the electrolyte, at the current density of 0.5 A/g, the specific capacitance of RGO-Ni(OH)2-2 can reach up to 1611 F/g, which is superior to Ni(OH)2 that not compound with three-dimensional graphene. At the current density of 8 A/g, the same results were obtained. It suggests that the electrochemical properties of Ni(OH)2 are effectively enhanced when three-dimensional graphene composite with PPDHCl.