In order to better analyze and to explain the electrochemical and physical behavior during both charge and discharge of a manganese dioxide based ECs, an original electrochemical model is developed in this paper. The 1D model is an adaptation of the transmission line model (TLM), taking into account the cation diffusion in the solid oxide. A linear relation between redox potential and oxidation state is used and leads to a physical relation between its slope and the pseudo capacitance of the material, confirmed by an experimental investigation of cyclic voltammograms. The model can be applied for any metal oxide pseudo-capacitive material.