Evaluation of Space Charge and Capacitance of Electric Double Layer Capacitor using Ionic Liquid

Abstract

In this study, space charge distribution in Electric Double Layer Capacitor (EDLC) for energy storage has been examined by Pulsed Electro-Acoustic (PEA) Method. Also, ketjen black was used for polarized electrodes instead of conventionally used acetylene black in order to improve the capacitance of 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. Therefore, the space charge and capacitance of prepared EDLC using ionic liquid was evaluated. As the results, it was found that the ketjen black containing EDLC showed fairly high charge density and high capacitance compared to acetylene black containing one. In addition, temperature characteristic of EDLC containing ketjen black and acetylene black with best quantity were measured on temperature from 0degC to 50degC. It is understood that ketjen black as conducting material and ionic liquid based EDLC was superior to organic electrolyte based EDLC in all temperature on capacitance. Also, internal resistance of EDLC containing ketjen black and ionic liquid based EDLC can be decrease.