The Effect of the Ratio of KOH to Carbon on the Pore Structure and the Capacitance Characteristic of Activated Carbon

AbstrcatHigh specific surface area activated carbon (HSSAAC), prepared from phenolic resins through the activation of KOH, was applied to electric double-layer capacitor (EDLC). The effect of the mass of KOH on the absorption characteristic, the pore size distribution and the capacitance characteristic of the activated carbon obtained were investigated. It was found that the BET specific surface area (SSA), the total pore volume, the mesopore volume, the iodine adsorption value and the methyl-blue adsorption value of the activated carbon increased constantly with the increase of KOH. However, the specific capacitance first increased, then decreased and reached a maximum of 74.2 F/g when the ratio of KOH to carbon was 4. EDLC using this HSSAAC as the electodes had good charge/discharge performance and cycling, which could discharge not only at a small current density for a long time but also at a large current density for a short time.