(Invited) What’s Killing My Fuel Cell? a Retrospective on Polymer Fuel Cell Poisoning and Degradation Research

PEMFCs are subject to many mechanisms that abruptly decrease power output or slowly degrade long-term performance. Los Alamos National Laboratory researchers pioneered many experimental investigations and forensic characterization studies to explore these effects. These include catalyst degradation, membrane performance loss and failure, gas diffusion layer degradation, and fuel and air poisoning mechanisms. This retrospective highlights a 25+ year effort at understanding and mitigating these effects. In the early 1990s fuel cell performance loss was observed in fuel cells which by today’s standards, had relatively high catalyst loading and utilized thick Nafion 117 membranes [1]. Carbon monoxide was already well known to poison the hydrogen oxidation reaction. The processes of Pt coarsening, Pt-M, dealloying, carbon corrosion, membrane free radical attack, foreign ion-proton exchange, ammonia and sulfurous gas poisoning, were investigated in subsequent years. Many characterization techniques, in addition to voltammetry, were employed to study these processes including: XRD, SEM, EDS, TEM, XPS, XRF, X-ray microscopy & tomography, neutron imaging and ion and gas chromatography [2]. Modeling methods from atomistic calculations to macroscopic effective medium transport models were developed to further provide insights towards mechanisms and mitigation strategies. The efforts continue today as ultralow loading platinum group metal catalysts and alloys, PGM free electrocatalysts, supports and novel membranes are being evaluated for next generation fuel cells. References Wilson, M. S.; Garzon, F. H.; Sickafus, K. E.; Gottesfeld, S., Surface area loss of supported platinum in polymer electrolyte fuel cells. Journal of The Electrochemical Society 1993, 140(10), 2872-2877. Borup, R.; Meyers, J.; Pivovar, B.; Kim, Y. S.; Mukundan, R.; Garland, N.; Myers, D.; Wilson, M.; Garzon, F.; Wood, D., et.al, Scientific aspects of polymer electrolyte fuel cell durability and degradation. Chemical reviews 2007, 107(10), 3904-3951.