Electrophoretic deposition of manganese dioxide–carbon nanotube composites

Nanofibers of manganese dioxide have been prepared by a chemical precipitation technique. Electron microscopy studies of the nanofibers showed a large aspect ratio with a length ranged from 0.1 to 1 μm and a diameter of about 2–4 nm. Electrophoretic deposition (EPD) method has been developed for the fabrication of composite films containing manganese dioxide nanofibers and multiwalled carbon nanotubes (MWCNT) for application in electrochemical supercapacitors (ES). Film thickness was varied in the range of 1–20 μm by variation in deposition time and voltage. The method enabled the formation of porous nanostructured composite films with pore size of 10–100 nm. Cyclic voltammetry (CV) data for the films tested in the 0.1 M Na2SO4 solutions showed ideal capacitive behavior and high-specific capacitance (SC) in the voltage window of 0–1.0 V versus standard calomel electrode (SCE). Composite films showed higher SC compared to the films without MWCNT. The SC decreased with increasing film thickness and increasing scan rate. Obtained results indicate that EPD is a promising method for the fabrication of manganese dioxide electrodes for ES.