Peculiarities of Electrochemical Behavior of Porous Carbon Electrodes of Supercapacitors in Aqueous Solutions of Salts of Alkali Metals

Abstract

Electrochemical behavior of porous carbon electrodes with different densities (0.75 and 0.35 g/cm³) used in supercapacitors with aqueous solutions of lithium, sodium and potassium sulfates was studied. It was shown that Li₂SO₄ solution is the most suitable for high-density electrodes, whereas K₂SO₄ solution is better for low-density electrodes. Experimental data obtained by means of cyclic voltammetric and impedance curves demonstrate a mutual influence of the porous structure of the electrode materials and diameters of solvated and bare ions on the values of specific capacitance and resistance. This should be taken into account when an electrode/electrolyte system is chosen for high-efficiency energy storage devices.