Research On The Production Of Graphene By Cu-Ni Alloy Based Chemical Vapor Deposition And Their Electrochemical Properties

Graphene is a widely concerned material that exhibits extraordinary performance in areas such as optoelectronics and electronics,but its performance is severely affected by quality.Therefore,it is crucial to produce high quality monocrystalline graphene.High quality graphene films can be obtained by chemical vapor deposition through fine substrate treatment and process optimization.Copper and nickel are the two most commonly used alloy catalysts with different growth mechanisms.It is an important solution to combine copper and nickel alloys as a growth substrate with a reasonable combination of their advantages.The purpose of this study is to explore the process and mechanism of the preparation of graphene by Cu-Ni alloy substrate CVD method,and to study the effects of various processes on the growth of graphene on different components of copper and nickel alloys,and to apply the high quality graphene prepared to the structure of supercapacitor and study its electrochemical performance.In this paper,Cu Ni alloy was used as the growth substrate to prepare graphene by CVD method.The influence of CVD process parameters on the quality of graphene under different alloy compositions was studied.The best growth substrate and matching process parameters were explored.Single crystal graphene was prepared by controlling growth.The optimized graphene modified electrode is assembled into a super capacitor.The influence regularity and mechanism of graphene structure on the electrochemical performance of supercapacitor were studied.The main conclusion is that the alloy substrate needs to be electropolished beforehand and an appropriate time of annealing.The growth temperature,meth ane flow rate is directly proportional to the nucleation rate,size,and thickness of graphene.The hydrogen flow rate is also proportional to the nucleation rate of graphene;Ni atoms account for The ratio is positively related to the graphene size,thickness and wrinkle density,and negatively related to the single crystal;the best process parameters are Cu70Ni30 as the alloy substrate,annealing at 950° C.for 30 min,growth for 30 s,methane flow rate of 1 sccm,and hydrogen flow rate of 100 sccm.The graphene thickness is less than 2 nm and is single crystal growth.The modified graphene-assembled supercapacitor has a specific capacity of 169.99F/g in the cyclic voltammetry test,an increase of 30.78%,and a capacity retention rate of 78.68%.In the constant current charge-discharge test,the specific charge capacity reached 100.74F/g,and the discharge specific capacity reached 107.35F/g,which increased by 14.41% and 19.49% respectively,and the retention rate reached 80.53 and 75.32%.The Coulomb efficiency reached 85% at a current density of 1 A/g.The idea of this paper is to control the composition of copper-nickel alloy and the process parameters of chemical vapor deposition method.High quality graphene is prepared and used in supercapacitors.Due to the wide application of graphene prepared by CVD method,And there are few reports on the application of CVD graphene in energy storage devices.Therefore,this study is of pioneering significance and practical value.