is used to define the stoichiometric coefficients, νi, with
νi being positive (
νred) for products and negative (
νox) for the reactants in a reduction reaction. The number of participating electrons,
n, is always positive.
The molar species fluxes, Ni (SI unit: mol/(m
2·s)), perpendicular to an electrode-electrolyte interface are calculated by summing all the flux contributions from the electrode reactions of index
m, according to Faraday’s laws:
where iloc,m is the local current density (SI unit: A/m
2) of the electrochemical reaction,
nm the number of participating electrons and
F (SI unit: C/mol) is the
Faraday constant. Note that
iloc,m denotes the current density perpendicular to the electrode surface.
The molar species flux, Ni, is obtained from the normal component of the molar species flux vector over the electrode-electrolyte interface:
where n is the normal vector of the boundary pointing into the domain.
where av,m (SI unit: m
2/m
3) is the specific surface area.