Attachment of Nickel Nanoparticles on Carbon Nanotube Electrodes for Enhancement of Electrochemical Capacitance
Multi-scale and/or multi-disciplinary approach to process-product innovation
Nanotechnology & Nanomanufacturing (T3-1P)
Keywords: carbon nanotubes; electric double-layer capacitance; nickel nanoparticle; pseudocapacitance; ac impedance
The present work demonstrated that the metallic Ni attachment was found to enhance the electrochemical capacitance of carbon nanotube (CNT) electrodes in KOH solution. A chemical impregnation leaded to homogeneously disperse Ni particle onto the surface of CNTs, which was oxidized by nitric acid treatment. The Ni particles were found to be an average size of 30–50 nm. Cyclic voltammery (CV) measurements showed that the presence of Ni particle significantly enhances the electrochemical capacitance. The Faradaic current (i.e., peak current) linearly increased with the Ni loading, indicating that the population of Ni coverage promotes the redox process. This indicates that attached nickel can be served as a redox site in facilitating an excess specific capacitance, i.e., pseudocapacitive behavior.
Equivalent circuit analysis on the ac impedance results showed that the total resistance of CNT electrodes was mainly attributed to the charge transfer and the electrical connection resistances. Both of the two resistances were found to decrease upon the introduction of nickel. This indicated that the Ni attachment would improve not only the conductivity of CNT electrodes but also the charge transfer of redox reaction. Due to the introduction of Ni, the overall specific capacitance was found to be a great value of 237 F/g. The linearity relationship between the total capacitance and the Ni loading reflected that each Ni particle has an identical electrochemical activity in KOH electrolyte at different Ni densities.
Presented Tuesday 18, 13:30 to 15:00, in session Nanotechnology & Nanomanufacturing (T3-1P).
