An EDLC comprises two electrodes immersed in either an aqueous or nonaqueous electrolyte, with a porous membrane serving as a separator and stores electric energy directly by forming an electrical double layer on the surface of the electrode. Upon applying a potential bias on an EDLC cell, solvated anions are electrostatically drawn to the positive electrode, while solvated cations migrate toward the negative electrode. This phenomenon leads to the series-connected EDLs facilitated by the presence of the electrolyte. The EDLC system is composed of two polarizable electrodes, and the accumulation of charges at the electrode/electrolyte interface is determined by equation .