Synthesis Of Graphene And Its Application In Supercapacitor

Based on the increasing electricity use and requests of solving global environmental problems,the ways,in which electricity is generated and used,Renewable energy resource has become critical as the request of electricity increasing.The utilization of electrical energy storage?EES?makes renewable resource more accessible to grid,so it has become a challenging issue to develop an efficient energy storage device.Supercapacitor is an environment friendly energy storage device,and its performance mainly depends on its electrode material.Graphene,an novel 2 dimensions carbon material,has some outstanding and intriguing features which made graphene become a promising material for energy storage devices,especially as a supercapacitor electrode material.Graphene supercapacitor become an novel supercapacitor.In this thesis,Hummer's method has been tried to make graphene.Hummer's method is an common method to prepare graphene-based electrode materials for supercapacitor.This method mainly use the strong oxidizer to exfoliate graphite to get graphene oxide colloid.Next,this graphene oxide colloid will be washed until the value of its pH reaching to 7,then hydrazine,a strong reductant,is used to convert the washed graphene oxide to graphene.During the synthesis process,it is necessary to find a way to keep the charges,to neutralize the electrolyte and to keep enough water within the dispersion.Graphene electrodes can be prepared with furnace annealing method in one step.According to various characterizations,characterization differences exists among the electrode materials,which annealed under different annealing temperature.The mass loss of the nickel foam has also been found.To foresee how good the graphene-based material can be and what problem we may face when we make supercapacitor with our own graphene material,graphene-based supercapacitor electrodes have been made with commercial graphene oxide and commercial graphene powder.In this thesis,three supercapacitor assembly forms have also been tried.The highest specific capacitance has reached to 33 F g^-1.