To explain induced polarization, membrane polarization is often referred to as a rele v ant process taking place in granular media -particularly, when narrow pore throats are present. This polarization effect is based on the membrane-like behaviour of pore throats caused by the presence of an usually ne gativ e charge on the pore surface, that influences charge transport in the pore fluid. Existing analytical, 1D models describe the pore system as a series of cylindrical pores with different radii and lengths. The polarization response is calculated by solving the Poisson-Nernst-Planck system for the current densities of one single anion and one single cation species representing the charge transport in the electrolyte and the diffuse layer at the pore surface. To include charge transport in the Stern layer, cations in the Stern layer have so far simply been considered by increasing the concentration of the diffuse layer cations. As we know from numerical modelling, this approach fails to predict the polarization response when the Stern layer is significantly charged. Here, we present a new semi-analytical model that treats the Stern-layer cations as a separate ion species and allows the Stern layer to polarize indi viduall y. To v alidate our ne w model, we compare it to the pre viousl y used anal ytical model and numerical simulations for different relative charges in Stern-and diffuse layer. We also use electrostatic surface-complexation models for two mineral surfaces (quartz and montmorillonite) to simulate the response of real geologic material under varying chemical conditions. This work is a step forward for considering realistic pore properties in inducedpolarization modelling.