Electrochemistry modeling of proton exchange membrane (PEM) water electrolysis for hydrogen production

An electrochemistry model was developed to analyse the J-V characteristics of a Proton Exchange Membrane (PEM) water electrolyser for hydrogen production. The Butler-Volmer equation and water transport characteristics through electrolyte membrane were employed to simulate the electrode activation overpotential and membrane ohmic overpotential, respectively. The modeling results are found to agree reasonably well with experimental data published in the literature. The parametric simulations show that the ohmic overpotential is relatively small with typical water content in the membrane. Compared with the cathode overpotential, the anode overpotential is more significant and constitutes the major source of voltage loss. The high anode overpotential is due to the relatively slow oxidation kinetics, which is related to anode material property and microstructure. This model can be integrated with a photovoltaic or wind turbine model to predict the performance of sustainable hydrogen production systems and optimise their designs.