Study On Manganese Dioxide Electrodes Material For Supercapacitor

In this dissertation, the manganese dioxide is used for the electrode material of supercapacitor. We use the liquid deposition method to prepare and modified the manganese dioxide, use the physical and electrochemical testing method such as XRD, TEM, CV, EIS, constant current charge-discharge to study the physical characteristics and electrochemical performance of the prepared manganese dioxide. The major study content is as follows:The manganese dioxide is prepared by pre-absorption liquid deposition method, and is characterized physically and electrochemically, which is found out to beα-MnO₂ grain. The method can efficiently decrease the internal resistance of electrode, and increase the specific capacitance of manganese dioxide material.The manganese dioxide prepared by liquid deposition method is processed in the protection of inert gas in different temperatures. After theα-MnO₂ is process in protection of inert gas in different temperature, the crystalline structure of then aren't changed. But the crystal system of the manganese dioxide processed in protection of inert gas in 350 DEG C and 450 DEG C, and the tetragonal system is changed to the orthorhombic system. The internal resistance of MnO₂ processed in 150 DEG C is lowest, and the MnO₂ processed in 250 DEG C has highest specific capacitance and worst stability.The electrode with different content of manganese dioxide is tested, and the electrode with the content of 70% manganese is found to have the lower internal resistance; the electrode is tested in different concentrations of Na₂SO₄ solution, and the internal resistance of the electrode in 1 mol/L Na₂SO₄ solution is lower.The manganese dioxide and the iron oxide are codeposited in liquid, which will influence the crystal formation and growth of each other. For the composite materials with different iron content, while the iron content is increased, the electrochemical reaction resistance and absorption resistance of composite electrode increase. The reversibility of the composite material with the ratio of Mn:Fe=20:1 is good, the specific capacitance is moderated, and the stability of capacitance is very well.