Study Of The Properties Of Electrode Materials Based On Graphene Supercapacitors

As a new kind of two-dimensional carbon material, Graphene has shown huge application value in the field of supercapacitor, semiconductor, lithium battery, opto-electronic devices, aerospace etc, because of its high specific surface area, good con-ductivity, extremely light weight and so on. In this paper, based on graphene, through the porous-processing, porous-graphene material and porous-graphene supercapacitor has been prepared;Simultaneously, we prepared CNTs@NiO complexes, then assemble porous graphene and CNTs@NiO complexes into asymmetric supercapacitor, The main research contents of this paper include the following aspects:(1)Adding pure cobalt into the graphene, after the treatment of physical and chemical processes, porous-graphene was prepared. The porous-graphene (DGNs) supercapacitor was successfully prepared by the compression process of porous graphene. holes and mesoporous structure of the nano size have been found on the surface or internal of the graphene through Porous-processing, the migration of charged particles through the hole subjected to smaller resistance, the ion shows better transfer charge ability and high energy has been transmitted rapidly. At the current density of 1A/g, the specific capacitance of original graphene supercapacitor and the DGNs supercapacitor are 52.8F/g and 75.8F/g respectively, the specific capacitance increased by nearly 43%.(2) The CNTs@NiO composites were successfully prepared by the reaction of CNTs with nickel nitrate and urea. Using porous graphene (DGNs) as the negative electrode material, the CNTs@NiO composite was used as the cathode electrode material, and then the DGNs//CNTs@NiO asymmetric supercapacitor was successfully fabricated. The DGNs//CNTs@NiO asymmetric supercapacitor shows ultralong cycling stability with nearly 87%capacitance retention after 1000 cycles. At the current density of lA/g, the energy density of DGNs symmetric supercapacitor is 10.52Wh/Kg, The DGNs//CNTs@NiO asymmetric supercapacitor reaches 21.44Wh/Kg. The reason why the performance enhanced may be that the change of the cathode or anode electrode materials of asymmetric supercapacitor, and the pseudocapacitance was introduced. At the same time, the voltage of the window of the asymmetric supercapacitor changes from 0-1V to 0-1.6V.