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Optimizing Reversible Exsolution and Phase Transformation in Double Perovskite Sr2Fe1.5-xCoxMo0.5O6-δ Electrodes for High-Performance Symmetric Solid Oxide Cells
Small ( IF 13.0 ) Pub Date : 2024-09-09 , DOI: 10.1002/smll.202401628
Hyejin Jeon 1 , Yo Han Kim 1 , Hyeonggeun Kim 2 , Hyeongwon Jeong 1 , Bo-Ram Won 1 , Wonjun Jang 1 , Chan-Ho Park 1 , Kang Taek Lee 2, 3 , Jae-Ha Myung 1
Affiliation  

Double perovskite (DP) oxides are promising electrode materials for symmetric solid oxide cells (SSOCs) due to their excellent electrochemical activity and stability. B-site cation doping in DP oxides affects the reversibility of phase transformation and exsolution, which plays a crucial role in the catalyst recovery. Yet, few studies have been conducted on this topic. In this study, the Sr2Fe1.5-xCoxMo0.5O6-δ (CSFM, x = 0, 0.1, 0.3, 0.5) DP system demonstrates modulated exsolution and phase transformation reversibility by manipulating the oxygen vacancy concentration. The correlation between Co-doping level and oxygen vacancy concentration is investigated to optimize the exsolution and phase transformation properties. Sr2Fe1.2Co0.3Mo0.5O6-δ (3CSFM) exhibits reversible transformation between DP and Ruddlesden–Popper phases with a high density of exsolved CoFe nanoparticles under redox atmospheres. The quasi-symmetric cell with 3CSFM shows a peak power density of 1.27 W cm−2 at 850 °C in H2 fuel cell mode and a current density of 2.33 A cm−2 at 1.6 V and 800 °C in H2O electrolysis mode. The 3CSFM electrode exhibits robust stability during continuous operation for ≈700 h. These results demonstrate the significant role of B-site doping in designing DP materials capable of dynamic phase transformation in diverse environments.

中文翻译:


优化高性能对称固体氧化物电池双钙钛矿 Sr2Fe1.5-xCoxMo0.5O6-δ 电极中的可逆溶出和相变



双钙钛矿 (DP) 氧化物因其优异的电化学活性和稳定性而成为对称固体氧化物电池 (SSOC) 的有前途的电极材料。DP 氧化物中的 B 位阳离子掺杂会影响相变和溶出的可逆性,这在催化剂回收中起着至关重要的作用。然而,关于这个主题的研究很少。在本研究中,Sr2Fe1.5-xCoxMo0.5O6-δ (CSFM, x = 0, 0.1, 0.3, 0.5) DP 系统通过操纵氧空位浓度表现出调制的溶出和相变可逆性。研究了 Co-掺杂水平与氧空位浓度之间的相关性,以优化溶出和相变特性。Sr2Fe1.2Co0.3Mo0.5O6-δ (3CSFM) 在 DP 和 Ruddlesden-Popper 相之间表现出可逆转变,在氧化还原气氛下具有高密度的溶解 CoFe 纳米颗粒。在 H2 燃料电池模式下,具有 3CSFM 的准对称电池在 850 °C 下的峰值功率密度为 1.27 W cm-2,在 H2O 电解模式下,在 1.6 V 和 800 °C 下的电流密度为 2.33 A cm-2。3CSFM 电极在连续运行 ≈700 小时期间表现出强大的稳定性。这些结果表明,B 位点掺杂在设计能够在不同环境中进行动态相变的 DP 材料中发挥着重要作用。
更新日期:2024-09-09
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