Influence of calcination temperature on physical and electrochemical properties of MnO2 nanoparticles synthesized by co-precipitation method

Abstract

Manganese dioxide nanoparticles were successfully synthesized by co-precipitation method using manganese acetate and potassium permanganate as the starting materials and calcined at 200–500 °C for 4 h in ambient air. Structural, morphological and electrochemical properties of all samples were investigated by X-ray diffraction technique (XRD), scanning electron microscope (SEM) and cyclic voltammetry technique (CV), respectively. The symmetric electrochemical cells were fabricated on 304-stainless steel as the electrode by doctor blade technique using polyvinylpyrrolidone (PVP)-KI as the gel electrolyte. The XRD results reveal that tetragonal structure of MnO2 could be synthesized by co-precipitation process with calcinations temperature at 400 °C for 4 hr. SEM images indicate that the size of MnO2 quasi-spherical powders are in nanoscale and transform into short rod under calcination temperature at 500 °C. The electrochemical properties results indicate that the electrochemical cell of MnO2 calcined at 300 °C with PVP-KI as the gel electrolyte shows a highest specific capacitance about 90.87 F/g at a scan rate of 100 mV/s.