Improved Redox Cycling Durability in Alternative Ni Alloy-Based SOFC Anodes

Repeated reduction and oxidation of metallic nickel in the anodes of solid oxide fuel cell (SOFC) causes volume changes and agglomeration. This disrupts the electron conducting network, resulting in deterioration of the electrochemical performance. It is therefore desirable to develop more robust an...

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Bibliographic Details
Published in:Journal of the Electrochemical Society 2020-01, Vol.167 (12), p.124517
Main Authors: Ishibashi, Yusuke, Matsumoto, Kohei, Futamura, Shotaro, Tachikawa, Yuya, Matsuda, Junko, Lyth, Stephen M., Shiratori, Yusuke, Taniguchi, Shunsuke, Sasaki, Kazunari
Format: Article
Language:English
Subjects:
Anode
Durability
Nanostructure
Ni-alloy
Phase stability
SOFC
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Summary:Repeated reduction and oxidation of metallic nickel in the anodes of solid oxide fuel cell (SOFC) causes volume changes and agglomeration. This disrupts the electron conducting network, resulting in deterioration of the electrochemical performance. It is therefore desirable to develop more robust anodes with high redox stability. Here, new cermet anodes are developed, based on nickel alloyed with Co, Fe, and/or Cr. The stable phases of these different alloys are calculated for oxidizing and reducing conditions, and their electrochemical characteristics are evaluated. Whilst alloying causes a slight decrease in power generation efficiency, the Ni-alloy based anodes have significantly improved redox cycle durability. Microstructural observation reveals that alloying results in the formation of a dense oxide film on the surface of the catalyst particle (e.g. Co-oxide or a complex Fe-Ni-Cr oxide). These oxide layers help suppress oxidation of the underlying nickel catalyst particles, preventing oxidation-induced volume changes/agglomeration, and thereby preserving the electron conducting pathways. As such, the use of these alternative Ni-alloy based cermets significantly improves the redox stability of SOFC anodes.
ISSN:0013-4651
1945-7111
DOI:10.1149/1945-7111/abac87