title: Evaluation of the Effect of Sulfur on the Performance of Nickel/Gadolinium-Doped Ceria Based Solid Oxide Fuel Cell Anodes.
abstract: The focus of this study is the measurement and understanding of the sulfur poisoning phenomena of Ni/gadolinium-doped ceria (CGO) based solid oxide fuel cells (SOFC). Cells with Ni/CGO10 and NiCu5/CGO40 anodes were characterized by using impedance spectroscopy at different temperatures and H2/H2O fuel ratios. The short-term sulfur poisoning behavior was investigated systematically at temperatures of 800-950 °C, current densities of 0-0.75 A cm-2, and H2S concentrations of 1-20 ppm. A sulfur poisoning mitigation effect was observed at high current loads and temperatures. The poisoning behavior was reversible for short exposure times. It was observed that the sulfur-affected processes exhibited significantly different relaxation times that depend on the Gd content in the CGO phase. Moreover, it was demonstrated that the capacitance of Ni/CGO10 anodes is strongly dependent on the temperature and gas-phase composition, which reflects a changing Ce3+/Ce4+ratio.
authors.affiliation: Institute of Engineering Thermodynamics, German Aerospace Center (DLR), Pfaffenwaldring 38-40, 70569, Stuttgart, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Riegraf
authors.affiliation: Institute of Engineering Thermodynamics, German Aerospace Center (DLR), Pfaffenwaldring 38-40, 70569, Stuttgart, Germany.
authors.forename: Vitaliy
authors.initials: V
authors.lastname: Yurkiv
authors.affiliation: Institute of Engineering Thermodynamics, German Aerospace Center (DLR), Pfaffenwaldring 38-40, 70569, Stuttgart, Germany.
authors.forename: Rémi
authors.initials: R
authors.lastname: Costa
authors.affiliation: Institute of Engineering Thermodynamics, German Aerospace Center (DLR), Pfaffenwaldring 38-40, 70569, Stuttgart, Germany.
authors.forename: Günter
authors.initials: G
authors.lastname: Schiller
authors.affiliation: Institute of Engineering Thermodynamics, German Aerospace Center (DLR), Pfaffenwaldring 38-40, 70569, Stuttgart, Germany.
authors.forename: K Andreas
authors.initials: KA
authors.lastname: Friedrich
mesh_terms: D002563:Cerium / Q000737:chemistry*; D004553:Electric Conductivity; D011211:Electric Power Supplies; D004563:Electrochemistry; D004566:Electrodes; D005682:Gadolinium / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry*; D010084:Oxidation-Reduction; D013455:Sulfur / Q000737:chemistry*; D013696:Temperature
chemical_list: D002563:Cerium; C030583:ceric oxide; D013455:Sulfur; D009532:Nickel; D005682:Gadolinium
keywords: electrochemistry; fuel cells; gadolinium; nickel; sulfur