GDC-Infiltrated La<sub>0.3</sub>Ca<sub>0.7</sub>Fe<sub>0.7</sub>Cr<sub>0.3</sub>O<sub>3-</sub> <sub>δ</sub> Symmetrical Oxygen Electrodes for Reversible SOFCs
Bibliographic record
Abstract
There is great interest in the development of reversible fuel cells, particularly reversible solid oxide fuel cells (RSOFCs). RSOFCs can run in both the electrolysis mode (SOEC) to electrolyze H2O to H2 or co-electrolyze CO2 and H2O to syngas when excess electricity is available, and then run in the fuel cell mode (SOFC) to convert H2 or syngas to electricity and heat when energy is needed. The primary goal of this work has been to develop new materials for highly efficient electrolyte-supported RSOFCs, based on La0.3M0.7Fe0.7Cr0.3O3- δ (M = Sr, Ca) mixed ionic-electronic conducting perovskite electrodes, with a particular forcus onLa0.3Sr0.7Cr0.3Fe0.7O3-δ (LSFCr) and La0.3Ca0.7Cr0.3Fe0.7O3-δ (LCFCr) operating in air at 600-800 oC. The specific goal of this work is to employ LSFCr and LCFCr as both the air and fuel electrodes in both the SOFC and SOEC modes, thus significantly lowering cost and simplifying the manufacturing process. Because of the excellent performance of LSFC [1] as an air electrode, efforts are now focussed on further improving its performance in air and also in fuel environments. For this reason, the A-site of the perovskite was doped with Ca in place of Sr, primarily to decrease the thermal expansion coefficient of the perovskite to more closely match that of the most commonly used electrolytes [2]. Although relatively low electrode polarization resistances were obtained with porous LSFCr [1] and LCFCr [2] electrodes, further improvement of the electrochemical performance would still be possible through microstructural modifications. Since the electrochemical performance of these mixed electronic and ionic conductors (MIECs) depends on the double phase boundary (DPB) area of the MIEC/electrolyte interface, in this study, an attempt was made to further enhance the DPB area by infiltrating the porous MIEC electrode with the electrolyte material (Gadolinia doped Ceria, GDC). To achieve this goal, a polymeric GDC solution precursor, which has the ability to form an interconnected film [3], was infiltrated into a previously sintered porous La0.3M0.7Fe0.7Cr0.3O3- δ scaffold structure. Two types of electrolyte supported symmetrical cells were used in this study. In Type 1, LSFCr and LCFCr were screen-printed on both sides of a 250 µm thick GDC electrolyte-support, followed by firing at 1100 oC in air. A second set of cells was then infiltrated with a polymeric GDC precursor (Type 2).The performance of these half cells, operated at 600-800 oC in air, was then investigated. The initial impedance spectroscopy results showed that GDC infiltration resulted in a ca. 3 fold decrease in the polarization resistance of the MIEC electrodes in air at 800 °C. The 0.06 Ω.cm2 polarization resistance obtained for these electrodes at this temperature is a strong indication that polymeric GDC precursor infiltration into MIEC electrodes is a promising approach for the fabrication of very high performance RSOFC electrodes. Acknowledgements: We are very grateful to the SOFC Canada NSERC Strategic Research Network, as well as Carbon Management Canada, for the support of this work. . References: [1] M. Chen, S. Paulson, V. Thangadurai and V. Birss, J. Power Sources, 236 (2013) 68. [2] B. Molero-Sanchez, J. Prado-Gonjal, , D. Ávila-Brande, M. Chen, E. Morán, E. and V. Birss, International Journal of Hydrogen Energy-Accepted, (2014). [3] A. Buyukaksoy, V. Petrovsky and F. Dogan, J. Electrochem. Soc., 160 (2013) F482.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".