Study On The Electrical Properties Of The Composite Electrode Materials Of Nickel Cobalt Nickel For Supercapacitor

Super capacitor is a new energy device which is developed quickly and widely studied in the energy storage area,having advantages of high speed of charging and discharging,releasing of large current instantaneously,long service life,protection the environment and so on.The main reason for the use of the supercapacitor is the electrical performance of the electrode materials is not stable,the current research of composite supercapacitor electrode materials is more and more,become a new research and development focus.Since Geim and Novoselov were the first to prepare graphene in 2004,graphene has received extensive attention and a lot of research.Only one atomic thickness of graphene,with good physical,chemical,thermal and other properties,has become a hot new electrode materials.Metal oxide materials have been used in the supercapacitor electrode materials because of its low cost,wide source and excellent electrochemical performance.In this paper,the Modified Hummers method was used to prepare graphene oxide,and then the NiCo₂O₄/graphene composite electrode material was prepared by hydrothermal method.The contents of this paper are as follows:1.The preparation of graphene.The oxidation reduction method was used to prepare graphene,the effect of reduction time and reducing agent dosage on the structure of graphene was studied by control variable method.It turned out that the the prepared graphene is multilayer.The Raman showed that the D peak of the product further enhance which indicated the grapheme was successfully synthesisd.2.The preparation of NiCo₂O₄/Nickel foam.NiCo₂O₄ was grown on nickel foam by hydrothermal method as a electrode material,the structure,morphology and electrochemical properties of the materials were studied.The results show NiCo₂O₄ was in a sea urchin shape,having a lot of micro holes and was even grown on a three dimensional foam nickel substrate.Unique structure make it show excellent capacitance characteristics.In 1A·g^-1,the specific capacitance was 970 F·g^-1.After1000 cycles,the retention rate of capacitance was 82.5%.3.The preparation of NiCo₂O₄/graphene.The NiCo₂O₄/graphene composites were formed by hydrothermal method with graphene oxide as substrate.The structure,morphology,component and the electrochemical properties were used to study.The tests showed that the graphene and the NiCo₂O₄ are composite together,and the advantages of the graphene as sheet and the thin film are retained,and composite materials without a large amount of agglomeration.Electrochemical performance test showed the highest specific capacitance of the composite is 712.7 F·g^-1(1 A·g^-1).After 1000 cycles,the retention rate of capacitance was 82.6%.