Status of Hexis SOFC Stack Development and the Galileo 1000 N Micro-CHP System

Mai, Andreas; Iwanschitz, Boris; Weissen, Ueli; Denzler, Roland; Haberstock, Dirk; Nerlich, Volker; Sfeir, Joseph; Schuler, Alexander

doi:10.1149/1.3205520

Cited by 29 publications

(16 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, sulfur-containing impurities in most prospective SOFC fuels such as natural gas and biogas inevitably lead to considerable performance drops upon exposure to Ni-based anodes. Sulfur poisoning of the most commonly used Ni/YSZ cermet anodes has been widely investigated, both experimentally and theoretically, and was related to the Ni surface poisoning with elemental sulfur. − However, only a few studies have targeted the sulfur poisoning behavior of Ni/CGO anodes, although they are used in several commercial applications and have been shown to possess a significantly higher sulfur tolerance than Ni/YSZ. − Hydrogen oxidation on Ni/CGO was frequently assumed to proceed via the same reaction mechanism as on Ni/YSZ, where hydrogen spillover including electrochemical charge transfer at the triple-phase boundary (TPB) between Ni/YSZ/gas phase was shown to be the rate-limiting step. However, recent studies of Ni/CGO have suggested that the rate-determining charge transfer reaction is likely to happen at the CGO/gas-phase double layer (DPB) rather than at the TPB between Ni/CGO/gas phase.…”

Section: Introductionmentioning

confidence: 99%

Sulfur Poisoning of Electrochemical Reformate Conversion on Nickel/Gadolinium-Doped Ceria Electrodes

et al. 2017

View full text Add to dashboard Cite

The aim of the present study is the measurement and understanding of sulfur poisoning phenomena in nickel/gadolinium-doped ceria (CGO) based solid oxide fuel cells (SOFC) operating on reformate fuels. The sulfur poisoning behavior of commercial, high-performance electrolyte-supported cells (ESC) with Ni/Ce0.9Gd0.1O2−δ (CGO10) anodes operated with different fuels was thoroughly investigated by means of current–voltage characteristics and electrochemical impedance spectroscopy and compared with Ni/Yttria-stabilized zirconia (YSZ) anodes. Various methane and carbon monoxide containing fuels were used in order to elucidate the underlying reaction mechanism. The analysis of the cell resistance increase in H2/H2O/CO/CO2 fuel gas mixtures revealed that the poisoning behavior is mainly governed by an inhibited hydrogen oxidation reaction at low current densities. At higher current densities, the resistance increase becomes increasingly large, indicating a particularly severe poisoning effect on the carbon monoxide conversion reactions. However, the ability of Ni/CGO anodes to convert carbon monoxide even at H2S concentrations up to 20 ppm was demonstrated, while this was not possible for Ni/YSZ. The sulfur poisoning behavior of Ni/CGO in reformate fuels was fully reversible for short exposure times. From methane steam re-forming experiments, it is deduced that the Ni surface is blocked and, thus, the water-gas shift reaction is fully deactivated as well. However, electrochemical CO oxidation on the CGO surface was shown to be still active. The present results clearly demonstrate that the high sulfur tolerance of Ni/CGO not only is limited to H2/H2O fuel systems but also extends to CO-containing gases.

show abstract

Section: Introductionmentioning

confidence: 99%

Sulfur Poisoning of Electrochemical Reformate Conversion on Nickel/Gadolinium-Doped Ceria Electrodes

et al. 2017

View full text Add to dashboard Cite

show abstract

“…3 The good scalability, from stacks producing a few kW up to several MW, makes this technology very exible in terms of its applications, ranging from decentralised domestic electricity and heat generation to power plant scale energy production. 2,4,5 Due to their excellent performance in hydrogen fuel, Ni/YSZ cermets are the state-of-the-art anodes for both electrolyte as well as anode supported cell designs. However, they still suffer from some drawbacks, such as Ni agglomeration at high temperatures, 6 coking when using hydrocarbon fuels under low steam to carbon ratios, 7 sulphur poisoning, 8,9 and especially instability upon redox cycling (cyclic reduction and oxidation).…”

Section: Introductionmentioning

confidence: 99%

Modified strontium titanates: from defect chemistry to SOFC anodes

et al. 2015

View full text Add to dashboard Cite

Modified strontium titanates have received much attention recently for their potential as anode material in solid oxide fuel cells (SOFC). Their inherent redox stability and superior tolerance to sulphur poisoning and coking as compared to Ni based cermet anodes could improve durability of SOFC systems dramatically.Various substitution strategies can be deployed to optimise materials properties in these strontium titanates, such as electronic conductivity, electrocatalytic activity, chemical stability and sinterability, and thus mechanical strength. Substitution strategies not only cover choice and amount of substituent, but also perovskite defect chemistry, distinguishing between A-site deficiency (A 1Àx BO 3 ) and cationstoichiometry (ABO 3+d ). Literature suggests distinct differences in the materials properties between the latter two compositional approaches. After discussing the defect chemistry of modified strontium titanates, this paper reviews three different A-site deficient donor (La, Y, Nb) substituted strontium titanates for their electrical behaviour and fuel cell performance. Promising performances in both electrolyte as well as anode supported cell designs have been obtained, when using hydrogen as fuel.Performances are retained after numerous redox cycles. Long term stability in sulphur and carbon containing fuels still needs to be explored in greater detail.

show abstract

“…Since the conductivity of electrolytes has an exponential dependence on temperature [ 13 ], operating temperatures above 800 °C are required to achieve high specific power. Nevertheless, even now, the electrolyte supported design is popular among SOFC manufacturers [ 82 , 83 , 84 ].…”

Section: Classification Of Sofcmentioning

confidence: 99%

Classification of Solid Oxide Fuel Cells

et al. 2022

View full text Add to dashboard Cite

Solid oxide fuel cells (SOFC) are promising, environmentally friendly energy sources. Many works are devoted to the study of materials, individual aspects of SOFC operation, and the development of devices based on them. However, there is no work covering the entire spectrum of SOFC concepts and designs. In the present review, an attempt is made to collect and structure all types of SOFC that exist today. Structural features of each type of SOFC have been described, and their advantages and disadvantages have been identified. A comparison of the designs showed that among the well-studied dual-chamber SOFC with oxygen-ion conducting electrolyte, the anode-supported design is the most suitable for operation at temperatures below 800 °C. Other SOFC types that are promising for low-temperature operation are SOFC with proton-conducting electrolyte and electrolyte-free fuel cells. However, these recently developed technologies are still far from commercialization and require further research and development.

show abstract

Status of Hexis SOFC Stack Development and the Galileo 1000 N Micro-CHP System

Cited by 29 publications

References 1 publication

Sulfur Poisoning of Electrochemical Reformate Conversion on Nickel/Gadolinium-Doped Ceria Electrodes

Sulfur Poisoning of Electrochemical Reformate Conversion on Nickel/Gadolinium-Doped Ceria Electrodes

Modified strontium titanates: from defect chemistry to SOFC anodes

Classification of Solid Oxide Fuel Cells

Contact Info

Product

Resources

About