Titanium porous-transport layers for PEM water electrolysis prepared by tape casting

While the porous-transport layer (PTL) is a key component in PEM electrolyzers, it is one of the most
underexplored due to limited available structures. In this work, we present a novel PTL design for PEM
water electrolyzers enabled by a cost-effective, scalable tape-casting technique. A precise control of the
PTL pore structure is achieved by incorporating poreformers of various sizes, and by varying the titanium
and poreformer ratio. The structures are characterized with SEM and synchrotron X-ray computed
tomography imaging techniques. Comprehensive electrochemical performance analysis demonstrates
that higher titanium loading provides improved contact at the catalyst-layer/PTL interface but suffers
from severe mass-transport losses due to gas bubbles. We solve this mass-transport problem by mixing
in large poreformer beads that produce a highly porous structure with excellent gas removal properties
yet still maintaining mechanical integrity. The PTL fabricated with 60:40 Ti:PMMA ratio and 60 μm PMMA
bead size outperformed the standard commercial Ti powder-based PTL by 62 mV at 4 A/cm²