Abstract: Specific capacitance and charge-discharge rate of EDLC using activated carbon electrode were affected by the compositions of electrolytes, the conditions of charge-discharge and physical properties of activated carbon materials. The activated carbon electrode was prepared by dip coating method. Charge-discharge test and electrochemical experiments were carried out for various kinds of organic electrolytes. Effects of charge and discharge current density on the specific capacitance were studied. Characteristics of leakage current, self-discharge and time-voltage curves in optimum conditions of organic electrolytes were compared with conventional 1M-Et4NBF4/PC electrolyte. The EDLC using MSP-20(specific surface area: 2000 m2/g) electrode and 1M-LiPF6/PC-DEC(1:1) was exhibited th highest specific capacitance of 130 F/g and low polarization resistances. The EDLC using MSP-20 electrode at 1M-LiPF6/PC-DEC(1: 1) was small leak current of 0.0004 A for 15 min, long voltage retention of 0.8 V after 100 h and linear time-voltage curves with small IR-drop.
Key words: EDLC, Activated carbon, Organic electrolyte, Dip coating method, Leak current, Self-discharge