Preparation of high porosity carbon electrodes from raw needle coke and their characterization for EDLCs

A series of high porosity carbons were prepared from raw needle coke activated by KOH.Nitrogen adsorption was used to characterize the BET surface area and pore structure of the porous carbon.When the ratio of KOH to carbon powder is 7∶1 and the heat treatment temperature 850 ℃,the BET surface area of the porous carbon obtained is 2 728 m~2/g,the pore volume is 2.14 cm~3/g,the statistical average pore diameter is 4.4 nm,and ratio of the sum of macro and meso pore volume to the total pore volume is about 50 %.The performance of the porous carbon electrode in 30 % KOH was investigated.Its specific capacitance is 305 F/g,it has a relatively higher energy density,better power characteristics,and a more satisfactory electric double-layer capacitance performance than other samples.