Preparation of activated carbon aerogel and its application to electrode material for electric double layer capacitor in organic electrolyte: Effect of activation temperature

Carbon aerogel was chemically activated with KOH at various activation temperatures with the aim of improving the electrochemical performance of carbon aerogel for EDLC electrode. Electrochemical performance of activated carbon aerogel electrode was determined by cyclic voltammetry and galvanostatic charge/discharge methods using coin-type EDLC cell in organic electrolyte. Activation temperature played an important role in determining the electrochemical performance of activated carbon aerogel for EDLC electrode. Specific capacitance of activated carbon aerogel at a high current density (5 A/g) showed a volcano-shaped curve with respect to activation temperature. Excessively high activation temperature could have an adverse effect on the electrochemical properties of activated carbon aerogel due to the low electrical conductivity caused by a collapse of characteristic structure of carbon aerogel. Among the carbon samples, carbon aerogel activated at 800 °C with a high surface area and a well-developed porous structure exhibited the highest specific capacitance. In addition, carbon aerogel activated at 800 °C retained a considerable specific capacitance at a high current density even after 1000 cycles of charge/discharge. Therefore, it is concluded that carbon aerogel activated with KOH at 800 °C can serve as an efficient electrode material for commercial EDLC with a high power density.