Study On The Electrochemical Performance Of Cobalt-based Compounds Based On ZIF-67

Energy is the most important cornerstone to promote the rapid development of society.At present,we are increasingly concerned about the problem of energy depletion.The emergence of high-efficiency new energy storage devices provides a new direction for solving the above problems.In order to meet the needs of social development and the implementation of national policies,vigorously develop energy storage technology,develop renewable environmentally friendly green energy,and research and apply new energy storage technology has become the development trend of the future society.A supercapacitor is such an electrochemical energy storage device,which has good power characteristics,cycle stability,safety and environmental friendliness,and has a very broad development prospect.However,the current supercapacitors still have certain shortcomings,such as low energy density.People are committed to improving and enhancing the performance of supercapacitors through various means,so that they can be applied to our lives and realize the development of the energy storage industry.Change and further development.The research in this article is to prepare transition metal sulfides by chemical modification using the highly chemically stable ZIF-67 metal organic framework as a template.Such cobalt-based compounds have the characteristics of high specific surface area,high conductivity,and high reaction reversibility.Electrode materials with nano-spherical structures are prepared by hydrothermal method and made into supercapacitor electrodes for material characterization and electrochemical performance analysis.In this paper,three electrode materials are prepared to compare and analyze their supercapacitor performance,namely CoS₂@NiMo₂S₄,CoS₂@NiS₂ and NiCo₂S₄.The final purpose is to explore the electrochemical performance of the target material CoS₂@NiMo₂S₄.The main research results are as follows:On the basis of ZIF-67,the CoS₂@NiMo₂S₄ electrode material was prepared by a two-step hydrothermal method,and the electrode material was prepared and subjected to morphology,structure characterization and testing.In addition,CoS₂@NiS₂ and NiCo₂S₄electrode materials were prepared as a control group.The test results showed that the CoS₂@NiMo₂S₄ electrode combined showed more excellent electrochemical performance.When the current density is 1A g^-1,the specific capacity exhibited is 887 F g^-1.In the AC impedance test,it shows that it has the lowest charge transfer resistance and contact resistance.Finally,after the life test,the remaining performance of the CoS₂@NiMo₂S₄ electrode after the 1000-lap test is 60%of the highest specific capacity.The electrode material combined with its spherical structure and needle-like structure can be used as the electrode of the super capacitor to fully contact the electrode material with the electrolyte,which can effectively promote the diffusion of ions in the electrolyte to the inner area of the electrode material,so that the surface of the electrode material can fully Participate in the rapid charge and discharge process of supercapacitors,which in turn leads to an increase in the electrochemical utilization rate of the material.Lithium-sulfur battery is another kind of electrochemical energy storage device with great development potential.It has high energy density,low cost and environmental friendliness,and it is worthy of further study.In this paper,a high specific surface area transition metal sulfide electrode material with a spherical hollow structure prepared based on ZIF-67 is used to support elemental sulfur,which is fabricated into an electrode and assembled into lithium-sulfur batteries,and the electrochemical performance of the batteries is analyzed.In this paper,three electrode materials are prepared to compare and analyze their performance,namely NiCo₂S₄,Co₃S₄ and Co₃O₄.The ultimate goal is to explore the electrochemical performance of the target material NiCo₂S₄ as a lithium-sulfur battery cathode material.The main research results are as follows:The NiCo₂S₄ electrode material with a hollow open structure was synthesized and prepared by hydrothermal method,and the electrode was prepared and assembled into a button battery.The characterization and electrochemical performance analysis were performed.The Co₃S₄ and Co₃O₄ electrode materials were used as the control group.The test results show that the button-type lithium-sulfur battery made of NiCo₂S₄ electrode material as a support for elemental sulfur has the best overall performance.It has a high initial specific capacity of 1275 m Ah g^-1 at a current density of 0.2C and a rate of 10 times.It still has a high capacity of 925 m Ah g^-1,and the rate performance is very good.Finally,the cycle life test is carried out.After 300 cycles,it still has a capacity of 767.6 m Ah g^-1,and the capacity retention rate is about 60%.It has excellent cycle stability.