Intermediate temperature molten salt batteries are a promising alternative for grid-scale energy storage with several advantages over existing solutions. The cathode of some of these batteries is composed of a porous matrix of materials containing the metal backbone of the electrode, along with electrolyte components that vary and different locations or as the state of charge of the battery changes. In this work, we aim to analyze the influence of the microstructural properties of the cathodic region at different compositions for a Na-Zn (ZnCl₂) battery. Synthetic geometric models of the electrode at different compositions are generated and then the effective conductivity is estimated through numerical simulation of the current and potential distribution through the material. At a three-phase composition used by a typical electrode assembly, the effective conductivity is approximately three times larger than the electrolyte electrical conductivity.