Effect of Porous Structure of Electrodes on the Properties of AC/AC Edlc with Organic Electrolyte

Abstract

Electrochemical double layer capacitors (EDLC) are energy storage devices that utilize ion adsorption at the double layer. Their typical electrodes are porous, conductive materials, such as activated carbon. In the present study, activated carbon is derived from pine cone (pinus pinea). The activation process is carried out with the aid of activating agents ZnCl2 and H3PO4. The effects of impregnation ratio (mass of activating agents/mass of precursor), and activation temperature on the resulting porosity, pore size distribution and texture of the activated carbon are examined. Surface area and pore volume are measured by N2 adsorption at 77 K. Textural properties are characterized by HRTEM. To achieve high energy density, organic electrolyte (acetonitrile) is used with TEABF4 dissolved in it. Galvanostatic charge-discharge, cyclic voltammetry and electrochemical impedance spectroscopy are applied to assess electrochemical behavior. The effect of porous structure on the energy and power characteristics of the EDLC is determined and by manipulating the activation process of AC, the properties of EDLC are optimized.