Preparation Of Cobalt Acid-based Electrode Material And Study On Its Electrochemical Performance

In today's world,the rapid development of science and technology is also accompanied by many problems such as the exhaustion of fossil energy and the increasingly serious environmental pollution.Therefore,it is particularly important to develop recyclable and environmentally friendly energy storage devices.Among many energy storage devices,supercapacitors have attracted extensive attention from scientific researchers due to a series of advantages such as extremely fast charging and discharging capabilities,higher power density,and ultra-long cycle life.The supercapacitor is mainly composed of the following parts:electrode material,electrolyte and diaphragm,etc.,and the role of electrode material is particularly important.In recent years,cobalt acid-based spinel materials have been widely used in many fields.Although nickel-cobalt-based metal oxide materials usually have a higher specific capacitance,the lower electrical conductivity and smaller surface area lead to serious capacity degradation,thus limiting their applications.Based on this,researchers usually use methods such as doping,introducing oxygen vacancies,and designing specific structure morphologies to improve the electrochemical performance of cobalt acid-based spinel materials.In this paper,the preparation methods and electrochemical performance of Ni Co2O4 and Cu Co2O4 electrode materials are studied by adjusting the loading of different materials on foamed nickel and introducing oxygen vacancies.The electrode materials are obtained by hydrothermal and annealing methods,and the successfully prepared electrodes are tested by X-ray diffraction(XRD),Scanning electron microscope(SEM),X-ray photoelectron spectroscopy(XPS),cyclic voltammetry(CV),constant current charge and discharge(GCD),and alternating current impedance(EIS).Related characterization and electrochemical performance test of the material,the contents are as follows:1)By configuring different concentrations of nickel cobalt oxide solution to control the electrode material of different loadings on the foamed nickel.And its phase composition and microscopic morphology were characterized.In addition,in the three-electrode system,3M KOH aqueous solution was used as the electrolyte,and the material was subjected to related electrochemical tests.According to cyclic voltammetry and constant current charge and discharge tests,it was found that the material performed best when the load was 1.26 mg.When the current density is 1A g^-1,the specific capacitance exhibits an excellent capacity of 1845 F g^-1.Therefore,the electrochemical performance of the material can be greatly improved by adjusting the concentration of different nickel cobalt oxide loading on the nickel foam.2)Through a simple one-step hydrothermal method,thermal annealing in different atmospheres,successfully synthesized low-crystalline Cu Co2O4 electrode material L-CCO with oxygen-rich vacancies.According to the analysis of the electrochemical test results under the three-electrode system,the following conclusions are drawn:L-CCO shows a specific capacitance of 1214 F g^-1 at 1 A g^-1,which is much higher than that of H-CCO.This excellent pseudocapacitance performance is attributed to the low crystallinity of the L-CCO electrode,which has a mainly amorphous nanostructure and abundant oxygen vacancies,which can provide more reaction sites and rapid ion insertion.This results in a fast Faraday redox reaction and excellent rate capability.Oxygen vacancies can play an important role in enhancing electrochemical performance.When applied to other transition metal oxides,oxygen vacancies are also expected to play a role.In addition,the asymmetric supercapacitors with high power density and energy density we prepare will enrich the next generation of energy storage devices.