Redox flow batteries (RFB) provide efficient storage of renewable energy facilitating sustainable energy supply. Among various RFB, the vanadium cerium battery is distinguished with large storage potential and without phase transition during the redox reactions. Herein, a two-dimensional model of a slice of the cell in a vanadium cerium redox flow battery is developed for the first time. Electrochemical characterization of both the V(II)/V(III) and Ce(III)/Ce(IV) electrochemical systems in mixed acid media is conducted to obtain the key parameters of the model. The data obtained from the simulations is then validated against the results of real flow battery experiments exhibiting a good agreement. With the perspective of state-of-the-art design in RFB system management for future large-scale systems, state of charge deviation and flow efficiency, are introduced as innovative measures of lifetime and energy density of the battery. The illustrated effect of several parameters involved in the proposed model provides direction toward optimum design of RFB systems.