Regulating Water Transport Paths on Porous Transport Layer by Hydrophilic Patterning for Highly Efficient Unitized Regenerative Fuel Cells

• Novel amphiphilic patterned titanium porous transport layers (PTLs) significantly enhance the round-trip efficiency of unitized regenerative fuel cells (URFCs), achieving an impressive round-trip efficiency of 25.7% at a current density of 2 A cm-2. • The serpentine configuration of the patterned PTL excels in both fuel cell (FC) and water electrolyzer modes, resulting in a sevenfold increase in current density in FC mode compared to URFCs using hydrophilic pristine Ti PTLs. • UV/ozone patterning offers a low-cost and scalable method to create amphiphilic patterns on hydrophobic silanized Ti PTLs, enabling precise alignment with the bipolar plate flow field. • The serpentine-patterned Ti PTL effectively enhances oxygen removal in water electrolyzer mode and mitigates water flooding in fuel cell mode, ensuring uninterrupted water and gas flow.