Study On The Preparation And Properties Of ZnMn₂O₄ As Positive Electrode Materials For Aqueous Zinc Ion Batteries

Energy and pollution are non-negligible issues that need to be dealt with for human continuity and social progress.With the popularization of portable electronic equipment in people’s daily life,batteries have been widely used as an efficient electrochemical energy storage device.With its high theoretical capacity(819mA·hg^-1),low negative potential（-0.763 V vs.SHE）,and high cost performance,zinc ion batteries have become a type of battery in rechargeable water-based systems,and have gradually entered people’s field of vision.Despite these advantages,the key challenge of ZIBs is to solve the slower kinetic reaction generated by the electrostatic interaction of Znand the cathode material.The challenges related to zinc metal,including zinc dendrites and side reactions,severely hinder rechargeability.The performance of ZIB.The specific content is as follows:（1）Explore the preparation of nano-scale ZnMn₂O₄ by hydrothermal method.Explore the influence of hydrothermal temperature and hydrothermal time on the performance of ZnMn₂O₄.The ZnMn2O4 material synthesized by hydrothermal heating at 200C and then calcined in muffle furnace at 500C for 3 h has good properties.The results measured by XRD show that the main diffraction peaks of the material have high intensity and are well aligned with standard cards,indicating that the ZnMn2O4 prepared by this method has high purity and good crystallinity.SEM analysis shows that the material is uniform spinel-like and has a smooth surface.The BET results show that the material has a large specific surface area and a small pore size.The electrochemical performance test results of ZnMn₂O₄ show that the charge-discharge voltage range of ZnMn₂O₄ is within 0.8-1.8 V,and the current density is set to 100 mA·g^-1,the first discharge specific capacity of the material is89.08 mAh·g^-1,after 150 charge-discharge cycles The discharge specific capacity is still high 154.19 mAh·g^-1.（2）The cathode material ZnMn₂O₄@PPy was prepared by chemical oxidation method.Explore the electrochemical performance of ZnMn₂O₄ coated with several mass fractions.XRD and SEM results show that the ZnMn₂O₄@PPy sample synthesized after the pyrrole coating mass fraction x=2wt%has good purity and crystallinity,and the morphology is uniform.The electrochemical test of the material is carried out and the voltage range of the positive electrode material is set to be within 0.8-1.8 V,and the current density for the material is 100 mA·g^-1,The maximum discharge specific capacity can be reached.237.92mA·g^-1.（3）ZnMn₂O₄@PANI was prepared by chemical oxidation polymerization method.The electrochemical properties of polyaniline coated with different mass fractions.XRD and SEM results show that when the aniline coating mass fraction is x=2wt%,the ZnMn₂O₄@PANI sample has a large specific surface area.The electrochemical performance test of ZnMn₂O₄@PANI shows that the material has excellent electrochemical performance,The maximum discharge specific capacity can be reached.210.57mA·g^-1.