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

Highlights: • Sb-doped SnO₂ coated MnO₂ electrodes (SS-MnO₂ electrodes) are prepared. • The capacitive property and stability of SS-MnO₂ electrode is superior to uncoated MnO₂ electrode and SnO₂ coated MnO₂ electrode. • Sb-doped SnO₂ coating enhances electrochemical performance of MnO₂ effectively. • SS-MnO₂ electrodes are desirable to become a novel electrode material 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