Wang Pei, Wang Yifei, Zheng Hesheng, Feng Xingchen, Wang Xiaoyu, Feng Juntao, Wang Yijian, Cong Tao, Zhao Zhongyi, Ding Xifeng
School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
ACS Appl Mater Interfaces. 2025 Jul 9;17(27):39053-39063. doi: 10.1021/acsami.5c05155. Epub 2025 Jun 27.
Reversible protonic ceramic fuel cells (R-PCCs) offer efficient energy storage and conversion. Therefore, PCCs show significant potential to revolutionize the large-scale adoption of intermittent renewable energy sources. However, their performance is significantly hindered by the reduced oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) activities at air electrodes as the operating temperature decreases. Here, we synergistically developed a perovskite air electrode, (BaK)CoFeNbO ((BK)CFN, = 0.90, 0.95, 1.00, 1.05, 1.10), through nonstoichiometry design and a steam-induced surface reconstruction strategy. The introduction of nonstoichiometric ratios notably promotes surface reconstruction of the (BK)CFN air electrode, a process further amplified under humid air conditions. Compared to stoichiometric BKCFN, the nonstoichiometric (BK)CFN forms in situ exsolution BaCoO nanoparticles on the surface under water vapor, increasing electrocatalytically active sites. When employed as the air electrode in anode-supported R-PCCs, the (BK)CFN electrode, with 5% A-site excess, exhibited superior bifunctional catalytic activity. It achieved a polarization resistance as low as 0.057 Ω·cm at 700 °C in humid air with 3% HO, representing a 19.3% improvement over BKCFN (0.068 Ω·cm). Additionally, the single cell with the configuration of (BK)CFN|BZCYYb|Ni-BZCYYb reached a peak power density of 828 mW·cm and an electrolytic current density of 1.80 A·cm at 1.3 V under humid air at 700 °C. The single cell demonstrated excellent operational stability over 100 h in a humid air environment under step-potential test conditions. This study provides a promising strategy for designing high-performance air electrodes for R-PCCs, leveraging nonstoichiometric composition design and surface reconstruction, which has extended applications to other energy material fields.
可逆质子陶瓷燃料电池（R-PCCs）具有高效的能量存储和转换能力。因此，质子陶瓷燃料电池在大规模采用间歇性可再生能源方面具有巨大的变革潜力。然而，随着工作温度降低，空气电极上析氧反应（OER）和氧还原反应（ORR）活性的降低严重阻碍了它们的性能。在此，我们通过非化学计量设计和蒸汽诱导表面重构策略协同开发了一种钙钛矿空气电极（(BaK)CoFeNbO ，(BK)CFN， = 0.90、0.95、1.00、1.05、1.10）。非化学计量比的引入显著促进了（BK）CFN空气电极的表面重构，在潮湿空气条件下这一过程进一步增强。与化学计量的BKCFN相比，非化学计量的（BK）CFN在水蒸气作用下在表面原位析出BaCoO纳米颗粒，增加了电催化活性位点。当用作阳极支撑的R-PCCs中的空气电极时，具有5% A位过量的（BK）CFN电极表现出优异的双功能催化活性。在700°C、含3% HO的潮湿空气中，其极化电阻低至0.057 Ω·cm，比BKCFN（0.068 Ω·cm）提高了19.3%。此外，(BK)CFN|BZCYYb|Ni-BZCYYb结构的单电池在700°C潮湿空气中、1.3 V下的峰值功率密度达到828 mW·cm ，电解电流密度达到1.80 A·cm 。在阶跃电位测试条件下，该单电池在潮湿空气环境中100 h以上表现出优异的运行稳定性。本研究提供了一种利用非化学计量组成设计和表面重构来设计高性能R-PCCs空气电极的有前景策略，该策略已扩展应用于其他能源材料领域。
