Electrophoretic Nanotechnology of Composite Electrodes for Electrochemical Supercapacitors

The electrophoretic deposition (EPD) method has been developed for the fabrication of MnO2-multiwalled carbon nanotube (MWCNT) films for application in electrochemical supercapacitors (ESs). For MWCNT applications, which depend on electrical conductivity, it is challenging to achieve dispersion and EPD of pristine MWCNT and avoid defects due to chemical treatment or functionalization. An important finding was the possibility of efficient dispersion and controlled EPD of MWCNT using calconcarboxylic acid (CCA). Moreover, the use of CCA allowed efficient dispersion of MnO2 in concentrated suspensions and EPD of MnO2 films. The comparison of the experimental data for chromotrope FB (CFB) and CCA and chemical structures of the molecules provided insight into the mechanism of CCA adsorption on MnO2. The fabrication of stable suspensions of MnO2 nanoparticles containing MWCNT, and controlled codeposition of both materials is a crucial aspect in the EPD composites. The new approach was based on the use of CCA as a charging and dispersing agent for EPD of MnO2 nanoparticles and MWCNT. The deposition yield measurements at various experimental conditions and Fourier transform infrared spectroscopy data, coupled with results of electron microscopy, thermogravimetric, and differential thermal analysis provided evidence of the formation of MnO2-MWCNT composites. The electrochemical testing results and impedance spectroscopy data showed good capacitive behavior of the composite films and the beneficial effect of MWCNTs.