Abstract
Titanium is the state-of-the-art material for porous transport layers (PTLs) for proton-exchange membrane water electrolyzers (PEMWEs) due to its stability and intrinsic electrical conductivity. However, titanium can develop an passivating, insulating oxide layer under the conditions of the PEMWE anode, thus reducing the effective electrical conductivity and cell performance.1 Coating the titanium PTL with platinum group metals is typically used to protect against oxidation.2 The purpose of this work is to investigate dissolution rates of titanium PTLs with and without coatings and of the PGM coatings by measuring the concentrations of metallic species in an aqueous electrolyte as a function of applied potential and environment measured using inductively-coupled mass spectrometry (ICP-MS). Time and potential resolution of the dissolution rates were achieved by coupling an aqueous electrolyte electrochemical flow cell with an on-line ICP-MS. These studies are the basis for establishing the thermodynamic and kinetics of degradation processes to be used for modeling the degradation phenomena as a function of electricity profile at the single cell and stack level. Results of ex situ, post-test and operando X-ray absorption spectroscopy characterization of platinum PTL coatings will also be discussed.AcknowledgementsThis research is supported by the U.S. Department of Energy, Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office under the auspices of the H2NEW Consortium. Argonne National Laboratory is managed for the U.S Department of Energy by the University of Chicago Argonne, LLC, also under contract DE-AC-02-06CH11357.
Published Version
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