Enhancing Durability and Performance of Anion Exchange Membrane Water Electrolyzers Anodes through Optimized PTFE Wetproofing

Anion exchange membrane electrolyzers (AEMELs) are an emerging low-carbon hydrogen production technology that merges the advantages of alkaline and proton exchange membrane electrolyzers, enabling the use of PGM-free catalysts, environmentally benign materials, and high operating current densities. However, their performance remains limited in part by water management, which can come from problems related to wettability and bubble removal at the anode. To control electrode wettability, gas diffusion layers and porous transport layers (PTLs) often add hydrophobic polytetrafluoroethylene (PTFE). For carbon based electrodes, this has been extensively studies, but nickel-based PTLs are now common in AEMELs and wetproofing of Ni-based PTLs is almost completely unreported in the literature, making the optimal degree of hydrophobic wetproofing for Ni-PTLs unclear. In this study, Ni-based PTLs were modified via controlled dip-coating with polytetrafluoroethylene (PTFE) to tune their hydrophobicity. The effects of PTFE loading on microstructure, water transport, and electrochemical performance were evaluated using microscopy, polarization curves, and steady-state measurements. Results show that low PTFE loading improves mass transport, enhances catalyst layer adhesion, and increases cell durability, whereas higher PTFE contents reduce water availability and increase mass transfer overpotentials. This work establishes both a practical wetproofing method for Ni-PTLs and an optimal PTFE loading range to enable high-performance, durable AEMEL operation.