electrode current density, j

If the charging current is negligible, in the case of a single electrode reaction, the electrode current density (c.d.) of the electric current flowing through the electrode is related to the flux density of a species B by the equation:
j = n ν B −1 F N B e
where N B e is the normal component of the vector N B at the electrode-solution interface, n is the charge number of the electrode reaction and ν B is the stoichiometric number of species B. The ratio n ν B is to be taken as positive if the species B is consumed in a cathodic reaction or produced in an anodic reaction. Otherwise it is to be taken as negative. With the convention that the normal distance vector points into the electrolytic solution, a cathodic current is then negative, an anodic current positive.
Source:
PAC, 1981, 53, 1827 (Nomenclature for transport phenomena in electrolytic systems) on page 1835