Communication—Contribution of Catalyst Layer Proton Transport Resistance to Voltage Loss in Polymer Electrolyte Water Electrolyzers

Mass transport losses (eta(mt)(x)) play a significant role at high current densities in polymer electrolyte water electrolyzers (PEWEs). Previous work has shown that eta(mtx) depends on the porous transport layer (PTL) structure, although a clear correlation between the material morphology and eta(mtx) has not been established. In this work, we experimentally determine the overpotential eta(H+)(CLa) associated with the proton transport in the anodic catalyst layer by measuring the ionic resistance in the catalyst layer using electrochemical impedance spectroscopy (EIS) and the transmission-line model. We found that overpotentials, including eta(H+)(CLa), depend on the PTL morphologic surface properties. (C) The Author(s) 2018. Published by ECS.