Preparation And Electrochemical Performance Of Graphene/Nickel-Cobalt Oxide/Polyaniline Nanocomposite

Supercapacitor is a novel type of energy storage devices with special properties,which has greater capacity,longer cycle life,and faster charge/discharge rate than the batteries.The electrode material has significance influence on the performance of the supercapacitor,which has emerged as a research hotspot.Reduced oxide Graphene?rGO?presents high electrical conductivity and high surface area,which has exhited excellent cycling stability.Therefore,it is one of the good supercapacitor electrode materials.However,due to its high degree of agglomeration,it is difficult to achieve its theoretical specific surface area in practical applications,then resulting in a reduction in its overall performance.Therefore,Co₃O₄-NiO?CN?is introduced between graphene sheets,which effectively reduced its agglomeration.At the same time,cobalt-nickel oxides as a typical pseudopotential capacitor material can be used to improve the composition,which provided pseudopotential for composite materials.The morphologies,structures and properties of rGO-CN were investigated via SEM,XRD,FT-IR,Raman measurements and electrochemical performance tests.The specific research content and conclusions were as follows:?1?GO was prepared by a modified Hummers method.rGO-CN composites was prepared by ultrasonication,hydrothermal process and calcining.The SEM results show that the cobalt-nickel oxide was embedded in the graphene layers,which could widen the space distance of the graphene sheets and prevent it from the stacking.XRD results showed that the nickel and cobalt elements in the material did not form a compound and existed in the form of Co₃O₄ and NiO.?2?Different molar ratios of nickel-cobalt have also conducted to investigate the electrochemical properties of the composite.Amogh them,rGO-CN had exhibited optimized electrochemical performance at the Ni–Co molar ratio of 1:1,which could reach at 278.6 F g^-1 at a current density of 1 A g^-1 and the capacitance retention was 96%for 1000 at 10 A g^-1,which display good electrochemical performance.Polyaniline?PANI?is an excellent supercapacitor pseudo-capacitive electrode materials because of its good electrical conductivity,low cost,easy synthesis,and multiple oxidation states.However,volume change of PANI during the charging and discharging process can lead to the its actual electrochemical performance to be poor stable.Therefore,on the basis of the above material preparation,rGO/Cobalt-Nickel Oxide/PANI?rGO-CN/PANI?composite was prepared by in-situ polymerization method and polyaniline?PANI?was decorated on the surface of rGO-CN nanocomposites.Thus,the volume change of PANI was controlled and pseudocapacitance was provided to the composite material.The specific study contents and conclusions were as follows:?1?The rGO-CN/PANI nanocomposites were fabricated by in situ polymerization of polyaniline.SEM studies show that the polyaniline was uniformly arranged in one-dimensional nanorods.The structure has a large specific surface area,which was contributed to the transmission of electrolyte ions.?2?The rGO-CN/PANI nanocomposites with different nickel-cobalt molar ratios were analyzed and their electrochemical performances were tested.The results show that the electrochemical properties of the rGO-CN/PANI nanocomposites prepared with a Ni–Co molar ratio of 1:2 were the best.The specific capacitance of rGO-CN/PANI was as high as 1400 F g^-11 at a current density of 1 A g^-1 and the capacitance retention was 85.7%when the current density is increased to 10 A g^-1,and it shows good electrochemical performance.The capacitance retention was 92%after the 1000 at 10 A g^-1.This results indicate that rGO-CN/PANI was expected to become a new generation of high-performance supercapacitor electrode materials.