Highly Conductive Mn-Co Spinel Powder Prepared by Cu-Doping Used for Interconnect Protection of SOFC
Mn-Co Spinel is considered as one of the most promising materials for the interconnect protection of solid oxide fuel cells; however, its conductivity is too low to maintain a high cell performance as compared with cathode materials. Element doping is an effective method to improve the spinel conduc...
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| Autores principales: | , , , , , , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
MDPI AG
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/58f8402395334058ab4807c14047bf84 |
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| Sumario: | Mn-Co Spinel is considered as one of the most promising materials for the interconnect protection of solid oxide fuel cells; however, its conductivity is too low to maintain a high cell performance as compared with cathode materials. Element doping is an effective method to improve the spinel conductivity. In this work, we proposed doping Mn-Co spinel powder with Cu via a solid phase reaction. Cu<sub>δ</sub>Mn<sub>1.5−x</sub>Co<sub>1.5−y</sub>O<sub>4</sub> with δ = 0.1, 0.2, 0.3, and x + y = δ was obtained. X-ray diffraction (XRD) and thermogravimetry-differential scanning calorimetry (TG-DSC) were used to evaluate the Cu-doping effect. After sintering at 1000 °C for 12 h, the yield exhibited the best crystallinity, density, and element distribution, with a phase composition of MnCo<sub>2</sub>O<sub>4</sub>/Cu<sub>x</sub>Mn<sub>3−x</sub>O<sub>4</sub> (x = 1, 1.2, 1.4 or 1.5). X-ray photoelectron spectroscopy (XPS) was used to semi-quantitatively characterize the content changes in element valence states. The areal fraction of Mn<sup>2+</sup> and Co<sup>3+</sup> was found to decrease when the sintering duration increased, which was attributed to the decomposition of the MnCo<sub>2</sub>O<sub>4</sub> phase. Finally, coatings were prepared by atmospheric plasma spraying with doped spinel powders and the raw powder Mn<sub>1.5</sub>Co<sub>1.5</sub>O<sub>4</sub>. It was found that Cu doping can effectively increase the conductivity of Mn-Co spinel coatings from 23 S/cm to 51 S/cm. Although the dopant Cu was found to be enriched on the surface of the coatings after the conductivity measurement, which restrained the doping effect, Cu doping remains a convenient method to significantly promote the conductivity of spinel coatings for SOFC applications. |
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