Electrical characteristics of double layer capacitor mixing Ketjenblack with surface functional group

Abstract

In this study, a high-capacity electric double layer capacitor (EDLC) was targeted, and an influence on a capacitance by a surface functional group of Ketjenblack (KB) powder as a conducting material of a polarized electrode was examined. Existence of an oxygen functional group on a surface of a carbon electrode in EDLC is related to a capacitance increasing with faraday reaction and improvement of wettability of a water solution electrolyte to an electrode. Therefore, EDLC was evaluated with different types of KB changing with quantity of a surface functional group. As the result, wettability of water solution electrolyte to the electrode was improved by increase of the surface functional group, and the capacitance was increased because osmosis of an ion became good. It is thought that the ion was adsorbed at the deep side of pore by the removal of the surface functional group, and it led to increase the capacitance of EDLC.