The Polymer Society of Korea

Abstract

Green hydrogen—central to deep decarbonization and long-duration storage—motivates PEM water electrolysis as a leading route with high current density and dynamic operation. Yet lowering Ir loading often produces anode losses not captured by bulk ohmics. Drawing on recent experiments and modeling, this talk isolates an ionomer-induced barrier to interfacial electron transport at the IrOx/TiOx/porous-Ti junction. Native n-type TiOx forms a Schottky-like barrier; when PFSA ionomer wets the PTL, mixed ionic/electronic contacts pinch off electron paths, increasing interfacial resistance. The barrier height scales with catalyst work function and ionomer–PTL contact area, so highly dispersed IrOx and dense layers aggravate losses at ultralow Ir. We propose design rules: restrict ionomer at the PTL, insert conductive or passivating interlayers, prefer lower-work-function IrOx facets, and tune particle size and porosity to preserve electronic percolation in low-PGM anodes.