In-situ Growth Of Nickel Selenide,Copper Selenide Nanomaterials And Their Electrochemical Properties

Supercapacitor is a kind of promising energy storage device whose electrode materials have been continuously explored.Compared with transition metal oxides,transition metal selenide have better electrical conductivity,and may be also used as supercapacitor electrode materials.In this paper,nano selenide(NiSe,Cu_1.8Se)in-situ grown on two common current collector?Ni,Cu?were synthesized and used as supercapacitor electrode materials.The synthesis methods of nano selenide with different morphology on metal substrate,as well as the supercapacitor energy storage mechanism,were researched.The detailed work was as follows:?1?The NiSe nanoarrays with average length of about 520nm were synthesized with adding surfactant by hydrothermal method,and the crystal structure,morphology and chemical composition was characterized using X-ray powder diffraction,field emission scanning electron microscope and energy disperse spectroscopy,and the influence of the addition amount of surfactant on the morphology and properties were also explored.The specific capacitance of NiSe@Ni electrode with 0.15g of laurel amide propyl betaine?LAB?could reach 1.55 F/cm² at a charge and discharge current density of 4 mA/cm²,and capacity would still maintain 67%at current density of 20mA/cm² after 1000 cycles.In addition,the NiSe//AC?activated carbon?asymmetric supercapacitor was assembled and the work voltage of the NiSe//AC asymmetric supercapacitor could reach to 1.6V in1mol/L KOH electrolyte,and the energy density could reach to 2.67mWh/cm³ in the power density of 46.2mW/cm³.In addition,its specific capacitance would maintain 72.7%of the initial value after 1600 cycles at the constant current density of 20mA/cm².?2?The Cu_1.8Se hierarchical structure with average thickness of about 55nm used as electrode material was prepared by hydrothermal method.The crystal structure,morphology and chemical composition were characterized by X-ray powder diffraction,field emission scanning electron microscope and energy disperse spectroscopy.And the influence of the reaction temperature on the morphology and properties were also explored and its transformational process under different potential windows in alkaline electrolyte?1 mol/L KOH?was also investigated.The morphology and composition of the electrode material of Cu_1.8Se hierarchical structure could be controlled by changing potential window of CV cycles.The CuO hierarchical structure with average thickness of about 15nm would be obtained by 35 cycles of CV from 0 to 0.6V,while the Cu?OH?₂ nanoarrys with average thickness diameter of about 105 nm would be obtained by 35 cycles of CV from 0 to 0.55V.To further investigate on the electrochemical performance of the device,the CuO//AC asymmetric supercapacitor?ASC?was assembled with CuO@Cu electrode materials as anode?as the larger specific capacitance?and the activated carbon as cathode materials.The energy density of CuO//AC ASC was up to as high as 85.03 Wh/kg at the power density of2505 W/kg,and the specific capacitance could still maintain 83%after 6500 cycles,indicating its excellent stability.