A Dynamic Model Incorporating the Effects of the Ion Diffusion and Side Reactions for the Vanadium/Air Redox Flow Battery

The vanadium/air redox flow battery working performance will be affected by many factors, including the quality of the membrane used and the working conditions. The crossover rate of vanadium ions for the membrane can determine the capacity due to the ion diffusion and the side reactions. The high reaction temperature for the VARFB also influence the diffusion coefficient. Based on Fick’s Law, by using Arrhenius Equation to predict the temperature effect, and take into consider that the mass balance for each reacting ions and reaction temperature, the dynamic modelling on capacity decay can be developed. Then by using Nernst Equation, the voltage change of VARFB can also be calculated. This dynamic model will predict the concentration change of the battery as a function of time, after benchmarking with the experimental data, this model can compare the performance of the battery with a different order of diffusion coefficient membranes in different working condition. This model can also predict the contacting V²⁺ concentration to the electrode and catalyst to monitor the working efficiency.