Voltage Window Test Of Conductive Metal-Organic Framework Ni₃(HITP)₂

The development and utilization of new energy has attracted more attention.In the new energy,solar energy and wind energy need the energy storage devices for peak shaving and valley filling.The popularity of electric vehicles also puts forward higher requirements for energy storage devices.Among energy storage devices,supercapacitors are widely used due to their high power density,long cycle life and wide operating temperature.In supercapacitors,electrode materials play a vital role.With the in-depth study,it is found that the pore structure of electrode has an important impact on the performance of supercapacitors.However,it is difficult for traditional carbon materials to accurately control the internal pore structure.Therefore,MOFs(Metal-Organic Frameworks),which can accurately control the pore structure,begin to be used in supercapacitors after solving the conductivity problem.As a new supercapacitor electrode material,conductive MOFs have many problems to be studied.We focused on the capacitance testing of conductive MOF Ni₃(HITP)₂in supercapacitors with ionic liquid electrolyte and the factors that affect the voltage window of Ni₃(HITP)₂.The main contents are as follows:In this thesis,SEM,TEM and specific surface area tests are used to determine the correctness of the crystal structure of the synthesized sample.On this basis,we test the capacitance of Ni₃(HITP)₂by different methods.The results illustrate the feasibility of Ni₃(HITP)₂ to be used in supercapacitors with ionic liquid electrolyte.In addition,we point out that the electrode manufacturing methods and the conductivity of ionic liquid have a great influence on the ESR of Ni₃(HITP)₂ supercapacitors by comparing the ESR of supercapacitors using different electrode manufacturing methods and ionic liquids.We study the voltage window of Ni₃(HITP)₂ in a three-electrode system.2 m V/s is recommended to judge the voltage window of Ni₃(HITP)₂ by analyzing the cyclic voltammetry curve with different sweep speed.The voltage window of Ni₃(HITP)₂ in ionic liquid[EMIM][BF₄]was measured to be-0.5 V-1.2 V,and the available operating voltage in two-electrodes supercapacitors is 1.6 V,exceeding the previously reported result(1 V).In addition,it is pointed out that the relevant research results can be improved through the comparison of different test methods,and using constant voltage method can get more accurate voltage window of Ni₃(HITP)₂ supercapacitor.Finally,we believe that ionic liquid has an important influence on the voltage window of Ni₃(HITP)₂by comparing the voltage window of Ni₃(HITP)₂in[EMIM][BF₄]and[BMIM][BF₄].