Organic carbonate-Organic ester-based non-aqueous electrolytes for electrical double layer capacitors

The electrical characteristics of the electrical double layer capacitors based on the nanoporous carbon|1 M triethylmethylammonium tetrafluoroborate in ethylene carbonate mixed with dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, methyl formate, methyl acetate and ethyl acetate in the 1:1 volume ratio have been studied using the cyclic voltammetry and the electrochemical impedance spectroscopy methods. The specific series and parallel capacitances, phase angle, time constant, series and parallel resistances dependent on the binary solvent system used have been established. The region of ideal polarisability of nanoporous carbon electrodes ΔE ⩾ 3.0 V for 1 M (C2H5)3CH3NBF4 in various binary non-aqueous solvent systems has been achieved. Specific conductivity values for 1 M TEMA solution in various organic carbonate-based electrolytes have been obtained at −40 °C < T < 50 °C and compared with the electrochemical data.