The good oxygen ion conductivity makes brownmillerites suitable as electrode materials for SOFCs. In this contribution, we focus on Ca2Fe1.95Mg0.05O5 (CFMO) with the idea of evaluating this brownmillerite as a promising innovative and low-cost cathode material. The synthesis was made through citrate route, where a magnesium doping was carried out to emphasize Fe3+/Fe4+ redox couple and thus the electronic conductivity. The chemical and physical properties of the material were verified by XRD, H2-TPR, XPS, BET and SEM techniques. The material was electrochemically characterized as a cathode by EIS, obtaining promising ASR values (0.19 Ωcm2 at 800 °C). Furthermore, CFMO stability under different atmosphere conditions was confirmed by EIS investigation at different oxygen partial pressures. The material was activated by deposition of FeOx nanoparticles through co-deposition and infiltration; the effect of increasing amount (10 and 15 wt %) was also studied. The Ca2Fe1.95Mg0.05O5 based nanocomposites well perform as cathode materials and the electrocatalytic reduction of oxygen is enhanced by iron oxide. This is confirmed by a reduction of ASR to 0.17 Ωcm2 at 800 °C for CFMO with Fe2O3 15 wt % as the best result of the study.
Ca2Fe1.95Mg0.05O5: Innovative low cost cathode material for intermediate temperature solid oxide fuel cell
Glisenti A.
2021
Abstract
The good oxygen ion conductivity makes brownmillerites suitable as electrode materials for SOFCs. In this contribution, we focus on Ca2Fe1.95Mg0.05O5 (CFMO) with the idea of evaluating this brownmillerite as a promising innovative and low-cost cathode material. The synthesis was made through citrate route, where a magnesium doping was carried out to emphasize Fe3+/Fe4+ redox couple and thus the electronic conductivity. The chemical and physical properties of the material were verified by XRD, H2-TPR, XPS, BET and SEM techniques. The material was electrochemically characterized as a cathode by EIS, obtaining promising ASR values (0.19 Ωcm2 at 800 °C). Furthermore, CFMO stability under different atmosphere conditions was confirmed by EIS investigation at different oxygen partial pressures. The material was activated by deposition of FeOx nanoparticles through co-deposition and infiltration; the effect of increasing amount (10 and 15 wt %) was also studied. The Ca2Fe1.95Mg0.05O5 based nanocomposites well perform as cathode materials and the electrocatalytic reduction of oxygen is enhanced by iron oxide. This is confirmed by a reduction of ASR to 0.17 Ωcm2 at 800 °C for CFMO with Fe2O3 15 wt % as the best result of the study.
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