Preparation of MnO2 electrodes coated by Sb-doped SnO2 and their effect on electrochemical performance for supercapacitor

Abstract

To enhance the specific capacity and cycling stability of manganese binoxide (MnO2) for supercapacitor, antimony (Sb) doped tin dioxide (SnO2) is coated on MnO2 through a sol-gel method to prepare MnO2 electrodes, enhancing the electrochemical performance of MnO2 electrode in sodium sulfate electrolytes. The structure and composition of SS-MnO2 electrode are characterized by using scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-Ray diffraction spectroscopy (XRD). The electrochemical performances are evaluated and researched by galvanostatic charge-discharge test, cyclic voltammogram (CV) and electrochemical impedance spectroscopy (EIS). The results show that SS-MnO2 electrodes hold porous structure, displaying superior cycling stability at large current work condition in charge-discharge tests and good capacity performance at high scanning rate in CV tests. The results of EIS show that SS-MnO2 electrodes have small internal resistance. Therefore, the electrochemical performances of MnO2 electrodes are enhanced effectively by Sb-doped SnO2 coating.