The Poisson-Boltzmann (PB) model, also known as the classical Gouy-Chapman model , uses dilute solution theory with point-like ionic species to model the electrical double layer which is assumed to be in quasi-equilibrium with the bulk. Similarly, the classical description from dilute solution theory of the dynamics of the double layer is given by the Poisson-Nernst-Planck (PNP) equations . However, it has been shown that the PB and PNP models break down dramatically at voltages much higher than the thermal voltage ( φ T = k B T /e = 25 mV, where k B is the Boltzmann constant, T is the temperature and e is the fundamental charge of the electron) which is the region of interest for electrocatalytic applications such as CO 2 ER.