Capacitance and Impedance Evaluations in Coconut Shells and Rice Husks Derived Activated Carbon Electrodes.

Abstract

Solid polarisable activated carbon electrodes have been prepared from Coconut shells and Rice husks. The preparation process involved precursor pre-carbonizations and conversion to solid carbon discs, inert environment carbonization and C0₂ activation at 750⁰C. Electrochemical Impedance spectroscopy characterizations gave their Double layer Capacitances as 0.02Fg^-1 and 0.17Fg^-1 respectively. The electrodes developed polarization impedances were 627.9? for the coconut shells and 1316.5? for the rice husks units. Their XRD scans showed that the electrodes were principally carbon and silica. The low polarization impedance of the coconut shell electrode was attributed to the activated petroleum residue tar binding material.

Keywords: Carbonization, Activation, Impedance spectroscopy, Polarization impedance, Double layer Capacitance