Study On Synthesis And Electrochemical Properties Of Manganese Oxide Supercapacitor Electrode Materials

In recent years,electrochemical supercapacitors have developed rapidly.Because of their high power density,fast charging and discharging time and good cycle stability,they are widely used in portable communications,transportation,power and aviation.Electrode material is the most important component of supercapacitor.And the electrochemical performance of supercapacitor is mainly related to the electrochemical performance of electrode material.Therefore,the research on electrode material of supercapacitor is extremely important.Theoretical specific capacitance of manganese trioxide(Mn2O3)can reach 1229 F·g?1.It has many advantages such as abundant electrochemical reactivity,low cost,environmental friendliness,large natural storage capacity and so on.It is a promising material for pseudocapacitor energy storage electrode.The main purpose of this paper is to obtain Mn2O3 electrode with excellent electrochemical performance by adjusting the preparation process parameters.The main work and conclusions of this paper are as follows:(1)Mn2O3 electrode materials with different morphologies were prepared by two-step method by using MnCl2·4H2O as manganese source and changing the kinds of surfactants,which were characterized by XRD and SEM.The results of electrochemical analysis show that electrochemical properties of Mn2O3 prepared by using CTAB and NH4F as surfactants are better than those prepared without surfactants.(2)Mn2O3 electrode materials with different morphologies were prepared by using NH4F as surfactant and changing hydrothermal time.The working electrode was prepared by binder-free method and its electrochemical performance was tested.The results show that the specific capacitance of the electrodes prepared by hydrothermal method with 6 h is the best.The specific capacitance can reach 856.1 F·g-1 at current density of 1 A·g-1.Furthermore,the specific capacitance can reach 62.97%of the initial value when current density is 5 A·g-1 and the cycle numbers are 1000 times.(3)Mn2O3 electrode materials with different morphologies were prepared by changing the amount of additives and using CTAB as surfactant.The working electrode was prepared by binder-free method and its electrochemical performance was tested.The results show that the performance of Mn2O3 electrode material prepared by adding 0.5 g of CTAB is the best.The specific capacitance can reach 495.0 F·g-1 when current density is 1 A·g-1.Furthermore,the specific capacitance is about 94.65%of the initial value when current density is 10 A·g-1 and the cycle numbers are 1000 times.(4)Mn3O4 and Mn2O3 electrode materials were prepared by two-step method under different calcination temperature by using manganese acetate as manganese source and isopropanol as solvent.The working electrode was prepared by coating method and its electrochemical performance was tested.The results show that the electrode material prepared at 550 ? has the highest specific capacitance,which can reach 425.53 F g-1 when current density is 1 A·g-1.Furthermore,the specific capacitance is about 53.88%of the initial value when electrode is circulated 1000 times at current density of 5 A·g-1.