Optimization of manganese dioxide-multiwall carbon nanotube composite electrodes for supercapacitor applications

Abstract

Manganese dioxide-multiwall carbon nanotube (MnO₂-MWCNT) nanocomposites were synthesized via one-pot synthesis method with varying concentrations of 1 mg/ml, 4 mg/ml, and 10 mg/ml MWCNT. The synthesized nanocomposites were characterized using x-ray diffraction (XRD), transmission electron microscopy (TEM), and electrochemical measurements. The intent of studying different concentrations is, ultimately, to correlate the effect of the concentration of multiwall carbon nanotube on the electrochemical performance of the MnO₂-MWCNT nanocomposites_. Two primary phenomena were observed as CNT concentration increased. First, less crystalline MnO₂ adsorption onto individual CNTs occurred. Subsequently, CNT agglomeration became the primary feature of the nanostructures of high CNT concentration. The electrochemical studies reveal that the specific capacitance of MnO₂ increases from 124 F/g to 145 F/g by the addition of 1 mg/ml MWCNTs and decreases to 102 F/g for MnO₂-10 mg/ml MWCNT nanocomposite.