Thermodynamics and Kinetics of the Interaction of Carbon and Sulfur with Solid Oxide fuel Cell Anodes

Abstract

Fuel cells are likely to play a key role in any low-carbon economy. Solid oxide fuel cells (SOFCs) are currently capable of sustained and continuous operation on high-purity fuels, but they must demonstrate that they can overcome a number of challenges before they are commercially viable on a large scale. Fuels such as natural gas, and those derived from renewable sources such as gasified biomass, contain many contaminants, typically sulfur-and carbon-containing compounds. To address this it will be necessary to improve our understanding of failure modes in operating SOFCs, and act on this to reduce degradation rates. A combination of techniques will be needed to develop a rigorous approach to understanding and mitigating degradation. The intent of this article is to present a synopsis of the current state of the art in our understanding of the effect of carbon and sulfur on SOFC anodes. Emphasis is placed on the comparison between thermodynamic and kinetic models, and experimental validation of these. In particular the applicability of thermodynamic models to the study of such contaminants is questioned. Additionally the uses of multiscale kinetic models capable of predicting transient conditions are reviewed alongside recent analytical techniques necessary for their validation.

The effect of current density on H2S-poisoning of nickel-based solid oxide fuel cell anodes

“…Sulphur is known to be a poison to nickel and other catalysts [1][2][3][4][5][6][7][8], but it is expensive to remove completely, and the effects of sulphur on SOFC anodes are not yet fully understood. There have been many previous studies, mostly on Ni-YSZ anodes with H 2 /H 2 S fuel mixtures, across a wide range of H 2 S concentrations (0.05 ppm to several thousand ppm) and temperatures (600-1000 • C) [3,8,9].…”

Thermoelectric characterization of an intermediate temperature solid oxide fuel cell system directly fed by dry biogas

“…biogas, bioalcohol, biodiesel, etc.) that generally contain an important level of contaminants, is extremely high [7]. The state-of-the-art anode of commercial SOFCs (nickel-yttria stabilized zirconia, Ni-YSZ cermet) is particularly sensitive to such risks, which would increase in favor of an irreversible cell degradation due to carbon deposition [8,9] and sulfur poisoning.…”

Preparation and characterization of La9.33Si6O26 powders by molten salt method for solid electrolyte application

“…Currently, yttria-stabilized zirconia (YSZ) with fluorite structure is the most common electrolyte material for SOFCs due to its excellent ionic conductivity and negligible electronic conduction at elevated temperatures (850-1000 • C), and good chemical stability. Nevertheless, this high operating temperature causes problems in terms of materials selection and lifetime [1][2][3][4]. So people search for alternative functional materials with higher ionic conductivity at relatively lower temperature [2,5].…”