Use the Porous Matrix Double-Layer Capacitance subnode to define a nonfaradaic double-layer current density at the interface between the porous electrode matrix and the electrolyte. The resulting double-layer current source in the Porous Electrode domain depends on the time derivative of the potentials and is proportional to both the Electrical double-layer capacitance Cdl (SI unit: F/m2) and the Double-layer area av,dl (SI unit: 1/m). The node can be added as subnode to a Porous Electrode node.

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).