title: Metallic plate corrosion and uptake of corrosion products by nafion in polymer electrolyte membrane fuel cells.
abstract: Nafion contamination by ferrous-alloy corrosion products, resulting in dramatic drops of the Ohmic potential, is a suspected major failure mode of polymer electrolyte membrane fuel cells that make use of metallic bipolar plates. This study demonstrates the potential of scanning transmission X-ray microscopy combined with X-ray absorption and fluorescence microspectroscopy for exploring corrosion processes of Ni and Fe electrodes in contact with a hydrated Nafion film in a thin-layer cell. The imaged morphology changes of the Ni and Fe electrodes and surrounding Nafion film that result from relevant electrochemical processes are correlated to the spatial distribution, local concentration, and chemical state of Fe and Ni species. The X-ray fluorescence maps and absorption spectra, sampled at different locations, show diffusion of corrosion products within the Nafion film only in the case of the Fe electrodes, whereas the Ni electrodes appear corrosion resistant.
authors.affiliation: Dipartimento di Ingegneria dell'Innovazione, Universita del Salento, Via Monteroni, 73100 Lecce, Italy. benedetto.bozzini@unisalento.it
authors.forename: Benedetto
authors.initials: B
authors.lastname: Bozzini
authors.forename: Alessandra
authors.initials: A
authors.lastname: Gianoncelli
authors.forename: Burkhard
authors.initials: B
authors.lastname: Kaulich
authors.forename: Maya
authors.initials: M
authors.lastname: Kiskinova
authors.forename: Mauro
authors.initials: M
authors.lastname: Prasciolu
authors.forename: Ivonne
authors.initials: I
authors.lastname: Sgura
mesh_terms: D003343:Corrosion; D004563:Electrochemistry; D004566:Electrodes; D004573:Electrolytes / Q000737:chemistry*; D005465:Fluorocarbon Polymers / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008567:Membranes, Artificial; D008853:Microscopy; D009532:Nickel / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D014867:Water / Q000737:chemistry; D056928:X-Ray Absorption Spectroscopy
chemical_list: D004573:Electrolytes; D005465:Fluorocarbon Polymers; D008567:Membranes, Artificial; D014867:Water; C040402:perfluorosulfonic acid; D009532:Nickel; D007501:Iron