Cu, Zn Co-doped ruddlesden-popper La1·2Sr0·8NiO4+δ oxides as high-performance air electrodes of medium-temperature protonic ceramic electrolysis cells

• Published in: Journal of power sources Vol. 597; p. 234141
• Main Authors: Wang, Zhengfeng, Miao, Xiaoyun, Zhu, Xingzhi, Guo, Shihang, Han, Donglin, Ye, Xiaofeng, Wen, Zhaoyin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.03.2024
• Subjects: Air electrode; Ruddlesden-popper oxide; Stability; Steam electrolysis; Triple-conducting; Triple-conducting; Ruddlesden-popper oxide; Stability; Air electrode; Steam electrolysis
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2024.234141

The Ln2NiO4+δ compound (Ln = La, Pr, Nd) finds extensive use as a cobalt-free oxygen electrode material in protonic ceramic electrolysis cells (PCECs) owing to its unique RP-type structure and remarkable catalytic activity. In this study, Cu and Zn co-substitution is employed to fabricate a series of materials, within the La1·2Sr0·8Ni0.5CuxZn0.5-xO4+δ system (x = 0.1, 0.2, 0.3, 0.4, denote as LSNCZ14, LSNCZ23, LSNCZ32, and LSNCZ41), and the crystal structure, conductivity, proton absorption and electrochemical properties are comprehensively investigated. The LSNCZ41 exhibits the lowest polarization resistance of 0.83 Ω cm2 at 600 °C in the symmetric cell. The PCEC single cell incorporating the LSNCZ41 air electrode demonstrates a high electrolysis current density of 1.5 A cm−2 (1.3 V) at 600 °C under 60 % humidity in air, furthermore, negligible degradation is observed under this high current density during electrolysis for over 250 h. These results indicate that LSNCZ41 possesses a higher concentration of interstitial oxygen ions and superior proton absorption capacity, significantly expediting the oxygen reduction reaction (ORR) and ionic transport processes. This material can be considered as a promising candidate for the PCEC air electrodes due to its superior stability in air with high steam content. •Co-substituting Cu and Zn in La1·2Sr0·8NiO4+δ promotes sintering and conductivity.•LSNCZ41 exhibits heightened interstitial oxygen and improved proton absorption.•LSNCZ41 presents triple conducting behaviors and 0.83 Ω cm2 of Rp at 600 °C.•The LSNCZ41-cell achieves stable electrolysis at 1.5 A cm−2 (1.3 V), 600 °C.