The Double-Layer Capacitance node describes the nonfaradaic currents due to charge and discharge of the double layer situated at the interface between the electrode and the electrolyte. The resulting double-layer current density on the boundary depends on the time derivative of the potentials and is proportional to the Electrical double-layer capacitance Cdl (SI unit: F/m2). The parent node may be either an Internal Electrode Surface or an Electrode Surface.

Use the settings of the Stoichiometric Coefficients section (not available in the Primary or Secondary Current Distribution interfaces) to control what species are participating in the double-layer charging — that is, the mass exchange between the double layer and the electrolyte outside the double layer.

The stoichiometric coefficients, νi, should be chosen considering the situation when the porous electrode is being cathodically polarized. In other words, use a negative stoichiometric coefficient for ions (species Si) that are transported into the double layer of the electrode that is being cathodically polarized (typically the cations), and positive stoichiometric coefficients for ions (species Si) that are transported out of the double layer (typically the anions).