Computational multiphysics modelling of Proton Exchange Membrane Water Electrolysis systems (PEMWE)

The climate crisis demands a rapid global shift from fossil-based systems to carbon-neutral technologies, with renewable energy and green hydrogen playing central roles. Proton Exchange Membrane Water Electrolysis (PEMWE) is one of the most promising technologies for high-purity hydrogen production thanks to its high efficiency, fast response, and ability to operate at elevated current densities and pressures. However, challenges remain, including high material costs, limited durability, and the need for performance optimization.

Water electrolysis splits liquid water into hydrogen and oxygen through the Oxygen Evolution Reaction (OER) at the anode and the Hydrogen Evolution Reaction (HER) at the cathode. A PEMWE cell is a multilayer structure composed of flow-field contact plates, Porous Transport Layers (PTLs), Catalyst Layers (CLs), and a Proton Exchange Membrane (PEM). Water is supplied to both electrodes: it is electrolyzed at the anode, oxygen exits through the PTL, and protons migrate through the PEM to the cathode where hydrogen is generated. The real operating voltage exceeds the reversible one due to activation, mass transport, and ohmic overpotentials. Durability remains a major limitation. Catalyst layers suffer from iridium dissolution and contamination from metallic cations, while PEMs can undergo mechanical damage under long-term operation.

These degradation processes are intensified at high current densities. Because PEMWE involves tightly coupled electro-chemo-hydro-mechanical phenomena, advanced numerical tools are essential. Finite Element simulations enable the analysis of stresses, transport processes, and electrochemical reactions under realistic conditions, providing insight into degradation mechanisms and operating limits. Combined with Machine Learning and Inverse-Design methods, these models support the optimization of porous layer microstructures, helping to improve mass transport, reduce losses, and extend system lifetime.