Dependence of electric double layer capacitance of activated carbons on the types of pores and their surface areas

The dependence of electric double layer capacitance on the pore structure of commercially available activated carbons in both nonaqueous and aqueous electrolytes was studied. Capacitance in the nonaqueous electrolyte (propylene carbonate solution of 1 mol/L triethyl-methyl-ammonium tetrafluoroborate) was linearly related to that in the aqueous electrolyte (1 mol/L H2SO4 solution). The contributions of the microporous surface area, Cmicro., and the surface formed on account of other large pores, Cext., were separately evaluated, the former being small and depending strongly on current density and the latter being almost constant.