Design,Preparation And Electrochemical Characterization Of Ni-Mn Sulfides And MnO₂ Electrodes For Supercapacitor Applications

Supercapacitors have the advantages of high power density,long circle life and strong adaptability to the working enviroment.They are one of the most important things in the power storage system for recent years.One of the factors which affecting the electrochemical performance of supercapacitors is the electrode.Transition metal oxides and sulfides have attracted wide attention among many electrode materials due to their high theoretical capacity and stable electrochemical performance.In this thesis,twokindsofsupercapacitorelectrodesaredesignedand fabricated.Nickel-based sulfides with high theoretical capacity and manganese-based sulfides and oxides with good stability were selected as research objects.The electrodes were prepared by one-step method and their electrochemical properties were improved by combining them with carbon cloth which possesses good conductivity.The main contents of this thesis is as follows:?1?The working principle and related testing methods of supercapacitors are systematically described,and the classification and research progress of electrode materials for supercapacitors are briefly introduced.?2?Nickel-manganese binary sulfides were grown on electrochemically treated carbon cloth by solution method,and the experimental conditions were adjusted to make the samples grown into lamellar particle-bound microstructures,so as to improve the electrochemical performance of the electrodes.The electrodes were further improved by using dispersant?sodium dodecylbenzene sulfonate?.It was found that appropriate dispersant could effectively help nickel-manganese binary sulfides to form uniform and uniformly distributed particles,thus exhibiting relatively good electrochemical performance.The area specific capacity of the electrode at 1 mA cm^-2is about 1480.25 mF cm^-2,and it remains about 700.00 mF cm^-22 when the current density rises to 10 mA cm^-2.?3?Using electrochemically treated carbon cloth as substrate,the foamed manganese oxide was further grown on the carbon cloth by solution method.By adjusting the experimental parameters,the foam structure of manganese oxide on the sample is more fluffy and complete,thereby having better electrochemical performance.The improved electrode has a wide voltage range of 0-1.1V,and exhibits a area specific capacity of 3705.08 mF cm^-22 at the current density of 1 mA cm^-2.Then in the long cycle test,the capacity remains at 1093.15 mF cm^-22 after 10 000cycles at the current density of 10 mA cm^-2,which ranks at the leading level of the same types of material.?4?The main research contents and related results are summarized,and the future development of the supercapacitors in this thesis is prospected.