Study On Metal Oxide Electrode Materials For Supercapacitors

Due to the advantages of high energy density,fast charge and discharge rate and long cycle life,supercapacitor have aroused great interest in academia and industry in the past few decades.The electrode materials,as the foremost part of supercapacitor,that are urgently needed to be developed need to have the following advantages,such as good cycle stability,low internal resistance,excellent rate performance,and low cost.In this paper,the transition metal oxide is used as the electrode material of the supercapacitor,and the hierarchical structure of the material is constructed.The relationship between the material structure and the electrochemical properties of the supercapacitor is studied,and the energy storage mechanism of the electrode of the pseudocapacitor is discussed.1.In this paper,the PN junction SnO@SnO2 hierarchical skeleton was cleverly designed,Co3O4 was introduced on its surface,and the electrode material of Co3O4-SnO@SnO2 flexible supercapacitor with hierarchical nanostructure was prepared by hydrothermal method.No adhesives are used in the case,can directly use hierarchical nanosphere structure Co3O4-SnO@SnO2 as working electrode in the three electrode system,has a low resistance(0.6 ?)and high conductive properties,showing high specific capacitance(1.056 F/cm-2 at the current density of 1 mA/cm-2)and excellent circulation stability,the initial specific capacitance lost only 8.5%after cycling 2000 times at a current density of 1 mA/cm-2.Studies on energy storage mechanism indicate that hierarchical Co3O4-SnO@SnO2 nanostructure is the main reason to improve the energy density and power density.2.The precursors were prepared by hydrothermal method on carbon cloth.After calcination,NiCo2O4@Co3O4 nanomaterials with hierarchical structure were obtained.By investigating the influence of calcination temperature on the electrochemical properties of the material,combined with X-ray diffraction and electron microscopy,it was found that at the calcination temperature of 350?,the outer layer of Co3O4 nanowire array was well coated with NiCo2O4,which formed a simple "Core-shell" cladding structure.Applying this oxide with hierarchical structure as the electrode material of the supercapacitor,it shows better performance.The specific capacitence is 0.959 F/cm-2 at a current density of 1 mA/cm-2,and 88%of the initial specific capacitance can still be retained after 2000 cycles of charging and discharging.