Electrophoretic Deposition of Manganese Dioxide−Multiwalled Carbon Nanotube Composites for Electrochemical Supercapacitors

Abstract

The cathodic electrophoretic deposition (EPD) method has been developed for the deposition of composite manganese dioxide-multiwalled carbon nanotube (MWCNT) films. Dopamine (DA) was shown to be an effective charging additive, which provides stabilization of manganese dioxide nanoparticles and MWCNTs in the suspensions. The influence of DA concentration on the deposition efficiency has been studied. EPD has been utilized for the fabrication of porous nanostructured films for application in electrochemical supercapacitors (ES). Obtained films were studied using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential thermal analysis (DTA), cyclic voltammetry (CV), and impedance spectroscopy. CV data for the films tested in the 0.5 M Na(2)SO(4) solutions showed capacitive behavior in the voltage window of 0-0.9 V. The highest specific capacitance (SC) of approximately 650 F g(-1) was obtained at a scan rate of 2 mV s(-1). The SC decreased with an increasing scan rate in the range of 2-100 mV s(-1). The deposition mechanism, kinetics of deposition, and charge storage properties of the films are discussed.