Preparation And Supercapacitive Performance Of Graphene Aedrogel Based Nanocompisites

In recent years,supercapacitor are paid more and more attention due to the power density,long cycle performance,fast charge and discharge advantages.The graphene-based composite aerogel has good electrical conductivity,environment friendly,high electrochemical activity and large theoretical surface area,is considered to be one of the most promising supercapacitor electrode materials.In this paper,graphene aerogel composite bimetallic oxide was used as the research topic.The composites based on graphene aerogel base were prepared by hydrothermal method and solvothermal method.The microstructure and electrochemical performance of the systhesised material was studied systematically.The main research contents are as follows:The graphene oxide was prepared by the improved Hummers method and the 3D graphene aerogel was prepared by hydrothermal method.Its unique structure can not only inhibit the re-stacking between graphene sheets,but also can be used in supercapacitors and other devices.As the electrode material,the active substance is directly pressed on the foam nickel,without the adhesive and the conductive agent,and the structural characterization and electrochemical performance of the graphene aerogel are tested.At a current density of 1A /g,the specific capacitance of the graphene aerogel is 197.5F/g,showing good electrochemical performance.On this basis,a 3D porous BWO-rGO composite aerogel was prepared by a mild hydrothermal method as a supercapacitor electrode material.Compared with pure BWO,the 3D porous composite showed better specific capacitance.At a current density of 0.75A/g,specific capacitance of the composite hydrogel was 268.7F/g,the capacitance retention rate is 81% after 1000 cycles of current at 3A/g.These significant electrochemical properties may be attributed to the unique structure of 3D porous rGO aerogels to support BWO.This structure provides an extraordinary conductivity substrate and ion diffusion channel.These results suggest that the 3D porous structure of aerogel-loaded bimetallic oxide is a new synthetic pathway that has potential applications in supercapacitor devices.In situ synthesized CoFe₂O₄/reduce oxygen graphene hydrogels?CoFe₂O₄-rGO?were achieved via one-step solvothermal approach.The three-dimensional?3D?network structure was constructed with multiple well-dispersed CoFe₂O₄ nanoparticles on the surface of graphene sketch.As a binder-free electrode material for supercapacitors,the electrochemical properties of CoFe₂O₄-rGO hybrid hydrogels can be adjusted by changing the content of grapheme oxide?GO?precursor solution.The hybrid material with 3.5mg/m L GO solution exhibits an outstanding specific capacitance of 356F/g at 0.5A/g,68% higher than that of the pure CoFe₂O₄?111F/g at 0.5A/g?.Additionally,an asymmetric supercapacitor based CoFe₂O₄-rGO and RGO was assembled,exhibiting a high energy density of 17.84 Wh kg-1at a power density of 650 W kg-1 and an excellent cycling stability with 87% capacitance retention at a current density of 5A/g after 4000 cycles.The results take one step further for the development of 3D aerogels supercapacitors and represent that the potential application of this hybrid material in energy storage devices.