Towards practicable methods for carbon removal from Ni-YSZ anodes and restoring the performance of commercial-sized ASC-SOFCs after carbon deposition induced degradation

Identification of carbon deposition and its removal in solid oxide fuel cells by applying a non-conventional diagnostic tool

“…1), as well as their impacts on the measurements, we refer the readers to previous studies. 58,59 The operating temperature was set at 800 C. Since the SOFCs used should be employed as a part of a system, lower operating temperatures are preferred. Both hydrogen and methane were used as fuels, while the cathode was supplied with synthetic air.…”

“…Its effectiveness has already been proven and described in previous works. 58,61 In those studies, carbon depositions could be completely removed and the initial cell performance could be regained in anode-supported SOFCs by feeding them with humidied hydrogen. Since the anode thickness is signicantly lower in the electrolyte-supported SOFCs used in this study, and because the mixed ionic/electronic conductor used had a lower propensity to deposit carbon, the overall regeneration time required could also be reduced.…”

Advanced Materials and Technologies for Fuel Cells

“…Nevertheless, the stability range of A 2 B 2 O7 compounds (being A and B transition metals or lanthanide ions) is reported to depend on the A/B cationic ratio, and all the ceria-based systems doped with lanthanide ions smaller than La (i.e., from Nd to Lu) have been determined to be more stable in the F phase [37]. Even the exhaustive paper by W. Chen and A. Navrotsky [38], which makes use of the atomistic results by L. Minervini et al [39], states that the formation enthalpies of Ce 2 RE 2 O 7 become thermodynamically unfavored when decreasing the RE 3+ size, being −102 kJ/mol for Ce 2 La 2 O 7 , −3.85 kJ/mol for Ce 2 Gd 2 O 7 and 175 kJ/mol for Ce 2 Y 2 O 7 . For the sake of completeness, simulations performed by B. Wang et al [40] showed that stable P defect clusters in Gd-doped ceria are expected to occur only when they form within ceria matrix domains in the sub-nanoscale range (i.e., at very low dopant amounts).…”

“…Four samples belonging to the Ce 1−x Gd x O 2−x/2 system having nominal x = 0.31, 0.34, 0.43, and 0.49 were prepared by co-precipitation of the corresponding mixed oxalates, as described in [37,38]. The co-precipitation technique was preferred to other synthetic methods, since it ensures a more intimate mixing of cations with respect for instance to solid state reactions, thus allowing a better homogeneity of the resulting samples [33].…”

2D Simulation for CH4 Internal Reforming-SOFCs: An Approach to Study Performance Degradation and Optimization

“…A further step consists of the analysis of occurring degradation and poisoning phenomena. In literature, they have been mostly investigated with experimental tests on both single cells [36] and stacks [37] as well as in terms of regeneration [38]. However, there are few modeling efforts that evaluate coking and H 2 S poisoning influence on electrochemical performance based on empirical [39] or theoretical formulation [40].…”