Preparation And Electronchemical Properties Of Solver Phosphate And Coballt Manganese Sulfide Electrode Materials For Supercapacitor

Supercapacitors,as a new type of energy storage device,have the advantages of high power density,fast charge and discharge and excellent cycle stability compared with traditional batteries,lithium-ion batteries and fuel cells,etc.,and have played an important role in many fields such as new energy vehicles,aerospace,industrial power and so on.The performance of supercapacitors mainly depends on electrode materials,so the research on new electrode materials of supercapacitors is a hot topic in recent years.Transition metal compounds have been widely studied and developed in the field of energy storage due to their high theoretical specific capacity and various electrochemical reactivity.Compared with carbon materials,transition metal compounds have lower mechanical stability and conductivity,which limit their applications.Phosphate and sulfide are rich in reserves,green,high specific capacity,very suitable for electrode materials.In this paper,two electrode materials,silver phosphate and cobalt manganese sulfide,were prepared respectively,and their energy storage performance was measured by three-electrode system.Specific research results are as follows:（1）Using Ag NO₃ and Na₂HPO₄·12H₂O as raw materials,flat spherical Ag₃PO₄nanoparticles were synthesized by liquid phase precipitation method,on this basis,the nitrogen-doped silver phosphate composite（N-Ag₃PO₄）was directly synthesized by mixing urea with Ag₃PO₄ through high temperature solid state reaction.The effect of N element content on its electrochemical properties was studied.SEM images show that both particle size and agglomeration degree of N-Ag₃PO₄ decreases,which is beneficial to reduce the ion migration path and increase the active site of electrode material.The discharge specific capacity of N-Ag₃PO₄-6 sample reaches 1314.9 F·g^-1 under the conditions of voltage changed range is 0-0.5V and current density is 1 A·g^-1in 1 M KOH electrolyte,the coulomb efficiency of all electrodes is above 95%.At a higher current density of 10 A·g^-1,N-Ag₃PO₄-6 sample is still possed a discharge specific capacity of 716.6 F·g^-1,showing a good rate performance.（2）Using Co（NO₃）₂·6H₂O,Mn（CH₃COO）₂·4H₂O and Na₂S as raw materials and CTAB SDS as surfactants,Co S,Mn S and Mn Co S were directly synthesized in situ on nickel foam by successive ionic layer adsorption and reaction（SILAR）.The electrochemical performance of Mn Co S composite is better than that of Co S and Mn S.SEM analysis shows that compared with the case without surfactant,the agglomeration phenomenon of particles in Mn Co S film is significantly reduced and the dispersion is significantly improved in the presence of CTAB or SDS,which is beneficial to reduce the internal resistance of electrode material,improve the conductivity of electrode material,and thus improve the electrochemical performance of Mn Co S The specific capacitance of Mn Co S-CTAB electrode reaches 2029.8 F·g^-1 at 1 A·g^-1,which is much higher than that of Mn Co S-SDS(1500.2 F·g^-1)and Mn Co S-H₂O(950.4 F·g^-1).The specific capacity at 10 A·g^-1 is 1371.9 F·g^-1,and there is still 974.0 F·g^-1 after 1000 cycles.The capacitance retention rate is 71%,showing good rate performance and long cycle life.The specific capacity ratio performance and stability are better than that of silver phosphate.（3）The preparation of nano thin films by successive ionic layer adsorption and reaction by surfactants has the advantages of simple operation,high specific capacity,good rate performance and good cyclic charge-discharge performance,and has a good application prospect.