Preparation And Electrochemical Performance Analysis Of Ion-intercalated Hydrotalcite Electrode Materials

In order to meet the electricity demand of electronic products,electric vehicles and other equipment,it is urgent to develop new energy storage devices with high specific capacity,high multiplier,green safety and good cycle life.At present,relatively mature lithium-ion batteries have many hidden dangers,such as poor stability,slow charging speed and so on.In order to solve these problems,electrode materials need to be designed and optimized and applied to energy storage devices to meet people’s urgent demand for energy.In this paper,electrode materials with high specific capacity,good rate characteristics and long cycle life,including positive electrode materials and negative electrode materials,were designed according to the demand of equipment electricity.In addition,the technological scheme of expanding the space between hydrotalcite layers and the corresponding electrochemical analysis were emphatically studied.The surface area of the prepared Ni-Al-MoO₄and Zn-Al-MoO₄materials is effectively increased by increasing the layer spacing,which promotes the contact between the electrolyte and the active material and improves the conductivity of the materials,thus obtaining excellent electrochemical performance.In the experiment of intercalated MoO₄^2-ions,the electrochemical performance of Moo₄^2-ions was improved by adjusting the concentration of salt ions and the content of molybdic acid.At the same time,on the basis of the above research,the device was assembled and the electrochemical performance was analyzed.The research contents are as follows:（1）Ni-Al-MoO₄hydrotalcite material was prepared by anionic intercalation of MoO₄^2-.Firstly,Ni-Al-CO₃material was prepared by hydrothermal method,and Ni-Al-MoO₄hydrotalc material was prepared by two time of anion intercalation by the methods of stripping-self-assembly-ion exchange.The structure and composition of the electrode materials were characterized by SEM,TEM,XRD,XPS and FT-IR,and the electrochemical performance of the materials was tested on the electrochemical workstation.At a current density of 1A g^-1,Ni-Al-MoO₄hydrotalcite material has a specific capacity of 1753.7F g^-1and a capacity retention rate of 62%after 200 cycles.When the power density is 776.5W kg^-1,the energy density is 39.7Wh kg^-1,and the capacity retention rate of the device is still above 60%after 500 cycles,which is based on Ni-Al-MoO₄as positive electrode and AC as negative electrode.（2）Preparation of Zn-Al-MoO₄hydrotalcite material by anion intercalation MoO₄^2-.Zn-Al-CO₃material was prepared by a two-step method.Since the magnification characteristics and cycle stability of the material were not ideal,Zn-Al-MoO₄was prepared by the method of stripping-self-assembly-ion exchange in order to obtain electrode material with good magnification performance and better cycle life.Using SEM,TEM,XRD,XPS,FT-IR and other methods to characterize the structure and composition of the electrode materials,it is found that Zn-Al-MoO₄hydrotalcite material has the advantages of high purity,less impurities,uniform size distribution,which is beneficial to maintain the electrochemical performance.In addition,the device assembled with Ni-Al-MoO₄prepared in chapter 3 was tested for its multiplier,cycle and practical application performance.The results show that the maximum specific capacity is 374.75m Ah g^-1at 1A g^-1current density,and 267.14m Ah g^-1when the current density is increased to 10A g^-1.At the same time,the capacity retention rate of the device is still more than 70%after 400 cycles of testing.