We focus on the decline in performance induced by the loss of wettability in the anode Porous transport layer (PTL) due to extended bubble coverage. We performed a series of multiple potentiometric tests including breaks every 10 hours combined with Electrochemical Impedance spectroscopy. Using this protocol, we obtain the variation in reaction Kinetics, Ohmic resistance and evolution of mass-transfer limit in the Anion Exchange Membrane Water Electrolysis (AEMWE). Our goal was to study the evolution of concentration overpotential in the AEMWE due to the variation in wettability. Our methodology was to characterize the two-phase flow properties in the PTL that plays a key role in the concentration overpotential at the electrode. It was performed using flow simulations with Geodict using 3D tomographic images of the Stainless steel (SS) PTL at the anode. These simulations were performed at the beginning of durability tests and the properties at the end of life were determined using a modified contact angle. We obtain the effective permeability of the medium to be implemented in the Darcy law as well as the capillary pressure at the electrode, for beginning and end of durability tests. Subsequently, these properties were implemented in our performance code to simulate the polarization curves at the beginning and end of life.

This work was performed at LMP, CEA Liten. For more information, do get in touch with me!