Synthesis And Electrochemical Performance Of Cobalt-based Nanocomposites For Supercapacitor

With the introduction of the National Development and Reform Commission’s dual-track policy on energy consumption,many provinces and cities were forced to cut off electricity due to insufficient power supply and environmental protection production restrictions.Due to severe energy pressure and environmental pollution,the development of energy storage technology needs to be solved urgently.Supercapacitors are considered to be the most promising new energy storage technology for efficient energy storage and release,and it has become a research topic currently supported by governments of various countries.However,with the continuous increase of market demand and the continuous expansion of application fields,supercapacitors are facing many problems.As the most important component of supercapacitors,the performance of electrode materials directly affects the overall device.Cobalt and chalcogen-related electrode materials have broad development prospects due to their higher theoretical specific capacitance and excellent conductivity.However,the research on how to further improve the related electrochemical performance is still shallow,and there are still many gaps to be filled.The main research contents of this thesis are as follows:1.Under the premise of synthesizing cobalt selenide Co Se materials,a one-step hydrothermal method was designed to successfully synthesize Co Se/Co Te nanocomposite electrode materials with different Te doping ratios,using field emission scanning electron microscopy(SEM),X-ray diffraction(XRD),and energy Spectrometer(EDS)and other analytical techniques are used to characterize the morphology and physical properties of materials.The electrochemical performance test shows that the ratio of Te:Se doping has a greater impact on the electrochemical performance of the material.The optimal doping ratio is 8%.At this time,the ratio of the electrode material at a current density of 5 A/g The capacitance reaches 887.3 F/g,which is an increase of 214% compared with the undoped condition.In addition,the prepared Co Se/Co Te and activated carbon electrodes are used to assemble an asymmetric supercapacitor,and its energy density and power density can reach 32.8Wh/kg and 800.5 W/kg.Exploring the influence of different doping ratios on the electronic structure through theoretical calculations shows that the chemical doping is an effective method to change the electronic properties and surface morphology of the material,and it can effectively improve the electrochemical performance of the doped electrode material.2.Exploring the optimal experimental process for synthesizing nickel-cobalt telluride NiCoTe2 material,using electrodeposition and hydrothermal two-step method to successfully obtain NiCoTe2 electrode directly grown on carbon cloth,study its electrochemical performance in detail,and compare it with Ni Te and Co Te tellurium Compare with chemicals.The prepared NiCoTe2 nanomaterial electrode has a mass specific capacitance of 924.01 F/g at a current density of 1A/g,and the assembled NiCoTe2//activated carbon asymmetric supercapacitor has a high energy density of54.0 Wh/kg and a power of 918 W/kg The density,and the specific capacitance retention rate after 5000 cycles is 90%,which is better than similar telluride materials reported in the past,proving that this material is a promising electrode material for supercapacitors.