Preparation Of Graphene By The Thermal Reduction Of Graphite Oxide And Study On Graphene-based Sulfides Composites For Supercapacitors

Graphene has a wide application prospect in the field of energy storage materials due to its unique physical and chemical properties,and graphene-based supercapacitors composites has been a hot area of research for several years.In this paper,graphite was oxidized to obtain graphite oxide,then the graphite oxide was rapidly heated to obtain graphene layers.XRD,FT-IR,TEM and other methods were used to discuss the effect of thermal reduction on samples.On the basis of this,copper sulfide-graphene composites and multiphase nickel sulfides-graphene composites were prepared by onestep hydrothermal method respectively.The structure and composition of the composites were characterized.The composite materials were used as electrode active materials for supercapacitors.The main contents and conclusions are as follows:1.The graphite oxide powder was sprayed directly to a hot plate,and the process was very short within 1~2 second.The results show that the structure of graphite oxide was gradually transformed to that of graphene.It is confirmed that the lamellar stacking structure of the graphite oxide underwent exfoliation and reduction during the rapid thermal reduction process to form the microcrystalline structure of the graphene.The surface and pore size analysis based BJH model show that,in this process,the reduced product at 500? hsa a specific surface area up to 737 m2?g-1 and a pore volume of 0.70 cm3?g-1?nm-1.This method is of great significance for the realization of large-scale industrial production of graphene.2.On the basis of preparation of graphene by thermal reduction,copper sulfidegraphene composites were prepared by one-step hydrothermal method.The copper sulfide,like spherical flower,grew on the surface of graphene substrate.Deionized water was used as reaction solvent,avoiding the use of organic solvent.This process is environmentally friendly.The electrochemical capacitance test showed that the specific capacitance was up to 1222.5 F?g-1 at 1 A?g-1 and the capacitance retention was 92.11% after 3000 charging/discharging cycles at 5 A?g-1.3.The heterogeneous nickel sulfides-graphene composites were prepared by onestep hydrothermal method.The nickel sulfide microspheres on the surface of graphene were mixed phases of various nickel sulfides(NiS,NiS2 and Ni3S4).The effects of reaction temperature and time on the structure and composition of the composites were discussed.The composites material were applied as electrode active material for the supercapacitor.The electrochemical capacitance test showed that the specific capacitance was up to 1602.2 F?g-1 at 1 A?g-1,with good rate characteristics and cycling stability(The capacitance retention is 90.81% after 3000 charging/discharging cycles at 5 A?g-1).