title: Degradation Study by Start-Up/Shut-Down Cycling of Superhydrophobic Electrosprayed Catalyst Layers Using a Localized Reference Electrode Technique.
abstract: Degradation of a polymer electrolyte membrane fuel cell (PEMFC) with electrosprayed cathode catalyst layers is investigated during cyclic start-up and shut-down events. The study is carried out within a single cell incorporating an array of reference electrodes that enables measurement of cell current as a function of local cathode potential (localized polarization curves). Accelerated degradation of the cell by start-up/shut-down cycling gives rise to inhomogeneous performance loss, which is more severe close to the gas outlet and occurs predominantly during start-up. The degradation consists primarily of loss of cathode catalyst activity and increase in cell internal resistance, which is attributed to carbon corrosion and Pt aggregation in both anode and cathode. Cells with an electrosprayed cathode catalyst layer show lower degradation rates during the first 100 cycles, compared with those of a conventional gas diffusion electrode. This difference in behavior is attributed to the high hydrophobicity of the electrosprayed catalyst layer microstructure, which retards the kinetics of corrosion of the carbon support. In the long term, however, the degradation rate is dominated by the Pt/C ratio in the cathode catalyst layer.
authors.affiliation: CIEMAT-Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas , Avenida Complutense 40, E-28040 Madrid, Spain.
authors.forename: Paloma
authors.identifier: http://orcid.org/0000-0002-0657-9936
authors.initials: P
authors.lastname: Ferreira-Aparicio
authors.affiliation: CIEMAT-Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas , Avenida Complutense 40, E-28040 Madrid, Spain.
authors.forename: Antonio M
authors.initials: AM
authors.lastname: Chaparro
authors.affiliation: CIEMAT-Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas , Avenida Complutense 40, E-28040 Madrid, Spain.
authors.forename: M Antonia
authors.initials: MA
authors.lastname: Folgado
authors.affiliation: CIEMAT-Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas , Avenida Complutense 40, E-28040 Madrid, Spain.
authors.forename: Julio J
authors.initials: JJ
authors.lastname: Conde
authors.affiliation: National Physical Laboratory , Teddington, Middlesex TW11 0LW, United Kingdom.
authors.forename: Edward
authors.initials: E
authors.lastname: Brightman
authors.affiliation: National Physical Laboratory , Teddington, Middlesex TW11 0LW, United Kingdom.
authors.forename: Gareth
authors.initials: G
authors.lastname: Hinds
keywords: Pt/C ratio; cathode localized potential; electrosprayed films; reference electrode array; start-up/shut-down degradation; superhydrophobic catalyst layer