To make matters simpler, we rewrite the integrals. First, when postulating that the derivative of 𝐺 in respect to the polarization is constant over a sufficiently wide potential range, the electrode becomes the form of an effective charge, 𝛿 𝑖 ⊖ (Eq. 3a). Secondly, the whole integral of the coverage 𝜗 𝑖 becomes an interaction function Λ 𝑖 (Eq. 3b). These are kinds of simplifications that are accepted in the B-V model.