Authors: A.S. Adekunle, K.I. Ozoemena, B.O. Agboola, E.E. Ebenso
Affilation: North-West University, South Africa
Pages: 472 - 475
Keywords: MWCNT-metal oxide nanocomposites, electrochemical impedance, galvanostatic charge-discharge, specific capacitance
Carbon based supercapacitor electrodes have been attractive due to their high surface area and porous nature. Studies have shown that the carbon nanotube-metal oxide (CNT-MO) nanocomposite modified electrodes exhibited huge capacitive current in some electrolytes. However, most reported work on this topic has been conducted in an alkaline environment. In this work, we established the supercapacitive behaviour of three transition metals (Ni, Co and Fe oxides) nanocomposite supported on MWCNT platform in acidic and neutral medium using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic constant current charge-discharge (CD) techniques. The specific capacitance (SC) values followed similar trend for the cyclic voltammetry and the electrochemical impedance studies and are slightly lower than values obtained using the galvanostatic charge-discharge cycling. MWCNT-NiO based electrode gave best specific capacitance in H2SO4. The value compared favourably and even better than values reported in literatures. The electrode demonstrated high stabilities with no significant changes over 1000 cycles.This synthesised MWCNT-NiO nanocomposite has demonstrated a great potential for energy storage in supercapacitors and an alternative to very toxic and expensive RuO2 material commonly used.