The Construction Of Ni-Co Layered Metal Hydroxide/Oxide In-Situ Growth System And Capacitor Performance

Due to limited crude oil storage and the gradual deterioration of environment situations,people's demand for new environmentally friendly energy sources is increasing.Among them,supercapacitors are considered to be one of the most potential new energy sources,which have the advantages of greater power density,instantaneous large current release and high charging and discharging efficiency.However,it still faces the defects of low energy density and low rate characteristics,therefore,the development of high-efficiency electrode materials for supercapacitors has important scientific significance.In this paper,transition metal oxide electrode materials,LDH electrode materials and Ni-Co LDH electrode materials derived from MOF were prepared by hydrothermal synthesis and electrodeposition.The morphology of the materials was observed by scanning electron microscope(SEM)and transmission electron microscope(TEM),and the structure and composition of the materials were characterized by X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).And its electrochemical performance was tested.The main research contents of this paper are as follows:1.The Co₃O₄ nanosheets were prepared on titanium mesh by hydrothermal synthesis.In this method,the prepared Co₃O₄ nanosheet has high surface area,porosity and long-distance two-dimensional conductive path,which makes it have low R_ct and good specific capacitance.The specific capacitance of Co₃O₄/Ti nanosheet electrode material is 67 F·g^-1 at the current density of 0.1 A·g^-1.2.The Co₃O₄@Ni-Co LDH composites for high performance supercapacitors were prepared by hydrothermal synthesis and electrodeposition.The composite material has large specific surface area and porosity,and the unique core-shell structure can obviously enhance the electrochemical performance of the composite material,so that it has a high specific capacitance of 1318 F·g^-1 at the current density of 0.5 A·g^-1.The prepared supercapacitor can have a high energy density of 46.3 Wh·kg^-1 and the power density of 64.2 W·kg^-1,and can light LED lamps,which proves that its application in high-performance supercapacitors is very promising.3.The Ni-Co LDH nanosheets derived from MOF were prepared by ion exchange method.The nanosheets prepared have large surface area,abundant active sites and good structural stability,which greatly improve the ion transmission efficiency and electrochemical performance of the materials.The nanosheets have a high specific capacitance of 2050 F·g^-1 at the current density of 1 A·g^-1.The supercapacitor has a high energy density of 27.39 Wh·kg^-1and the power density of 148.95 W·kg^-1,and can light the LED lamp.With its remarkable electrochemical performance,the device can become one of the promising candidates for energy storage system.