Basic Characteristic of Electric Double Layer Capacitor Mixing Ketjen Black as Conducting Filler

Abstract

In this study, ketjen black was used for polarized electrodes instead of conventionally used acetylene black in order to improve the capacitance of activated carbon-based Electric Double Layer Capacitor (EDLC). Usually, ketjen black exhibits higher electronic conductivity compared to acetylene black, so that ketjen black could be considered as conducting filler. Moreover, N₂ adsorption-desorption isotherm as well as TEM observation revealed that ketjen black used in this study has different type of pore structures compared to acetylene black. The capacitances of prepared EDLC were evaluated from discharge characteristics. It was found that the ketjen black containing EDLC showed fairly high capacitance compared to acetylene black containing one. Especially, 8 wt% ketjen black containing EDLC showed the highest capacitance among the prepared samples. The specific capacitance of the best one was evaluated as 59.2 F/g. It was also found that the 8 wt% ketjen black containing EDLC exhibited fairly stable capacitance at elevated tempareture from temperature dependence of capacitance for 10 wt% acetylene black containing EDLC and 8 wt% ketjen black containing one.