硅酸盐学报

固体氧化物燃料电池PrBaFe₂O₅₊_δ阴极材料的结构和氧还原反应机理

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薛柯 ¹^,²^,³ , 蔡长焜 ¹^,²^,³ , 谢满意 ¹^,²^,³ , 李舒婷 ¹^,²^,³ , 安胜利 ¹^,²^,³

硅酸盐学报 | 固体氧化物电池表界面专题—研究论文 2025,53(10): 3022-3030

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硅酸盐学报 |固体氧化物电池表界面专题—研究论文 2025 , 53 (10) : 3022 -3030

固体氧化物燃料电池PrBaFe₂O₅₊_δ阴极材料的结构和氧还原反应机理

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薛柯¹^,²^,³, 蔡长焜¹^,²^,³, 谢满意¹^,²^,³, 李舒婷¹^,²^,³, 安胜利¹^,²^,³

作者信息

^1．内蒙古科技大学，稀土产业学院（稀土工程技术学院），内蒙古包头 014010

^2．内蒙古科技大学，内蒙古自治区先进陶瓷材料与器件重点实验室，内蒙古包头 014010

^3．内蒙古科技大学，轻稀土资源绿色提取与高效利用教育部重点实验室，内蒙古包头 014010

通讯作者:

安胜利（1961—），男，博士，教授。

作者简介:

薛柯（1994—），男，博士研究生。

Structure and Oxygen Reduction Reaction Mechanism of PrBaFe₂O₅₊_δ Cathode Material for Solid Oxide Fuel Cells

Ke XUE¹^,²^,³, Changkun CAI¹^,²^,³, Manyi XIE¹^,²^,³, Shuting LI¹^,²^,³, Shengli AN¹^,²^,³

Affiliations

^1.School of Rare Earth Industry, Inner Mongolia University of Science and Technology, Baotou 014010, Inner Mongolia, China

^2.Inner Mongolia Key Laboratory of Advanced Ceramic Materials and Devices, Inner Mongolia University of Science and Technology, Baotou 014010, Inner Mongolia, China

^3.Key Laboratory of Green Extraction & Efficient Utilization of Light Rare-Earth Resources, Inner Mongolia University of Science and Technology, Ministry of Education, Baotou 014010, Inner Mongolia, China

Corresponding Author:

AN Shengli (1961-), male, Ph.D., Professor. E-mail: shengli_an@126.com

XUE Ke (1994-), male, Doctoral candidate. E-mail: xue_ke0@126.com

出版时间: 2025-10-20 doi: 10.14062/j.issn.0454-5648.20240682

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摘要

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PrBaFe₂O_5+δ（PBF）是中温固体氧化物燃料电池的阴极材料之一，然而PBF材料的结构还存在四方结构和立方结构的争议，并且氧还原反应机理还不清晰，需要进一步深入研究。目前的相关报道主要是对PBF材料的电化学性能进行优化，对结构和氧还原反应机理的报道较少。本工作通过密度泛函理论计算、X射线衍射、透射电子显微镜、电化学阻抗谱和弛豫时间分布法等方法研究PBF材料的晶体结构和氧还原反应机理，对PBF材料的合成过程、晶体结构和氧还原反应限制性步骤进行了详细分析。结果表明，由PrFeO₃和BaFeO₃在800 ℃固溶合成的PBF呈现四方结构（空间群：P4/mmm）。在空气和体积分数为20%的H₂（H₂+N₂）气氛中晶体结构稳定，在纯氢气中部分分解为Fe、BaFeO₃和Pr₂O₃。氧还原反应限制性步骤在400~550 ℃为氧原子电离和氧离子传输，600~700 ℃为氧气的化学吸附和氧分子的解离，700~800 ℃为氧气的物理吸附。

关键词

固体氧化物燃料电池 / 双钙钛矿 / 阴极 / 氧还原反应

Abstract

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Introduction

Compared to Co-based cathode materials, Fe-based perovskite materials exhibit superior thermal stability and electrochemical stability, but they have lower conductivity and redox activity. The Fe-based perovskite materials are regarded as one of the cathode materials with a great development potential for SOFCs due to their lower thermal expansion coefficient and cost. In the LnBaFe₂O₅₊_δ (Ln = lanthanide elements, Y) double perovskite materials, PrBaFe₂O_5+δ (PBF) has the lowest activation energy for the redox reaction, making it a promising alternative material for SOFC cathodes. For the PBF materials, there are a few reports on their crystal structure and redox reaction mechanisms. There is still a debate regarding the tetragonal and cubic structures of PBF materials. Also, the mechanism of the redox reaction remains unclear and requires a further in-depth investigation. This study was to prepare the PBF cathode materials by a sol-gel method. In addition, the synthesis process, crystal structure, and redox reaction mechanisms of PBF materials were also investigated.

Methods

The average binding energy of the possible structures of PBF was calculated by the Cambridge Sequential Total Energy Package (CASTEP) module in Material Studio software. The reflex module in Materials Studio was used to simulate the X-ray diffraction (XRD) patterns after optimizing the structures. The PBF powder was prepared by a sol-gel method, and the precursors were analyzed by thermgravity-differential thermal analysis (TG-DTA), X-ray diffraction (XRD) and transmission electron microscopy(TEM). The calcined samples were treated in air, 20% (in volume) H₂(H₂+N₂) atmosphere, and pure H₂ at 800 ℃ for 20 h. In addition, the electrochemical impedance spectra of the PBF|SDC|PBF symmetrical cell were measured, and analyzed via distribution of relaxation times (DRT).

Results and discussion

The simulated XRD patterns show distinct differences in the XRD peaks of the four PBF structures with the main difference between the tetragonal and simple cubic structures after 80°. The characteristic double peak of the double perovskite is attributed to an increased lattice distortion caused by an increase in oxygen vacancy defects, while its structural symmetry remains unchanged. The tetragonal structure has the lowest average binding energy, while the simple cubic structure has the highest. This indicates that the likelihood of PBF adopting a simple cubic structure is minimal, whereas the likelihood of it adopting a tetragonal structure is maximal.

The results of TG-DTA and XRD indicate that the precursors form BaFeO₃ and PrFeO₃ heat-treated at 800 ℃ and a subsequent two-phase solid solution process after 800 ℃. Pure PBF is obtained after roasting in air at 1200 ℃ for 5 h. In a 20%H₂(H₂+N₂) atmosphere, pure PBF can be achieved at 800 ℃, indicating that the 20%H₂(H₂+N₂) treatment accelerates the solid solution of BaFeO₃ and PrFeO₃. The PBF is structurally stable in both air and a 20%H₂(H₂+N₂) atmosphere, but decomposes into Fe, BaFeO₃, and Pr₂O₃ in pure H₂, indicating that PBF material decomposes under pure hydrogen and is not suitable for use on the anode side. Also, the occupancy of O in the [Pr-O] layer decreases, indicating that more oxygen vacancies are generated after reduction. The analysis of the crystal structure shows that the unit cell is elongated in a 20%H₂(H₂+N₂) atmosphere due to the formation of more oxygen vacancies in the [Pr-O] layer.

Based on the different relaxation times of various cathodic reactions, the DRT analysis indicates that the limiting step of the ORR at 400−550 ℃ involves the ionization of oxygen atoms and the transport of oxygen ions, while that at 600−700 ℃ involves the chemisorption of oxygen and the dissociation of oxygen molecules. At 700−800 ℃, the limiting step is related to the physisorption of oxygen. Clearly, the conclusions drawn from time-domain analysis differ from those obtained through conventional impedance spectroscopy. At 750−800 ℃, time-domain analysis indicates that the limiting step affecting the ORR is the physisorption of oxygen, whereas conventional impedance spectroscopy indicates that it is the ionization of oxygen atoms and the transport of oxygen ions. This study posits that both sets of results can serve as a basis for optimizing the oxygen catalytic performance of PBF materials.

Conclusions

This study investigated the formation process, structure, stability, and oxygen catalytic performance of PBF materials by DFT calculations, XRD, TEM, EIS, and DRT analysis. The PBF synthesized through the solid solution formation of PrFeO₃ and BaFeO₃ at 800 ℃ exhibited a tetragonal structure (i.e., space group: P4/mmm). The crystal structure remained stable in air and 20%H₂(H₂+N₂) atmosphere, but partially decomposed into Fe, BaFeO₃, and Pr₂O₃ in pure hydrogen. The limiting steps of the oxygen reduction reaction (ORR) were identified as the ionization of oxygen atoms and the transport of oxygen ions at 400−550 ℃, chemisorption of oxygen and dissociation of oxygen molecules at 600−700 ℃, and physisorption of oxygen at 700−800 ℃.

Key words

solid oxide fuel cell / double perovskite / cathode / oxygen reductive reaction

引用本文

薛柯, 蔡长焜, 谢满意, 李舒婷, 安胜利. 固体氧化物燃料电池PrBaFe₂O₅₊_δ阴极材料的结构和氧还原反应机理. 硅酸盐学报, 2025 , 53 (10) : 3022 -3030 . DOI: 10.14062/j.issn.0454-5648.20240682

Ke XUE, Changkun CAI, Manyi XIE, Shuting LI, Shengli AN. Structure and Oxygen Reduction Reaction Mechanism of PrBaFe₂O₅₊_δ Cathode Material for Solid Oxide Fuel Cells[J]. Journal of the Chinese Ceramic Society, 2025 , 53 (10) : 3022 -3030 . DOI: 10.14062/j.issn.0454-5648.20240682

基金

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国家自然科学基金(51974167)

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2025年第53卷第10期

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文章信息

doi: 10.14062/j.issn.0454-5648.20240682

接收时间：2024-10-29
首发时间：2026-10-21
出版时间：2025-10-20

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收稿日期：2024-10-29
修回日期：2024-12-07

基金

国家自然科学基金(51974167)

作者信息

^1．内蒙古科技大学，稀土产业学院（稀土工程技术学院），内蒙古包头 014010

^2．内蒙古科技大学，内蒙古自治区先进陶瓷材料与器件重点实验室，内蒙古包头 014010

^3．内蒙古科技大学，轻稀土资源绿色提取与高效利用教育部重点实验室，内蒙古包头 014010

通讯作者:

安胜利（1961—），男，博士，教授。

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https://castjournals.cast.org.cn/joweb/gsyxb/CN/10.14062/j.issn.0454-5648.20240682

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2种不同金属材料的力学参数

科 Family	属数 Number of genus	种数 Number of species	占总种数比例 Percentage of total species (%)	属 Genus	种数 Number of species	占总种数比例 Percentage of total species (%)
鹅膏菌科Amanitaceae	2	11	5.26	鹅膏菌属 Amanita	10	4.78
小菇科 Mycenaceae	2	12	5.74	丝盖伞属 Inocybe	5	2.39
多孔菌科 Polyporaceae	8	14	6.70	蜡蘑属 Laccaria	5	2.39
红菇科 Russulaceae	3	23	11.00	小皮伞属 Marasmius	6	2.87
				小菇属 Mycena	11	5.26
				光柄菇属 Pluteus	5	2.39
				红菇属 Russula	17	8.13
				栓菌属 Trametes	5	2.39

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