The effect of ceria content in nickel–ceria composite anode catalysts on the discharge performance for solid oxide fuel cells

• Published in: International journal of hydrogen energy Vol. 43; no. 4; pp. 2394 - 2401
• Main Authors: Inoue, Yuta, Hara, Kiyoto, Okudaira, Kenji, Ito, Hibiki, Ninomiya, Yoshihiko, Namioka, Tomoaki
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 25.01.2018
• Subjects: Electrical conductivity; Microstructure; Nickel–ceria composite catalyst; Porosity; Sintering; Solid oxide fuel cell; Nickel–ceria composite catalyst; Electrical conductivity; Porosity; Microstructure; Solid oxide fuel cell; Sintering
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2017.12.031

Optimum ceria content in nickel–ceria composite anode catalyst from the point of discharge performance is discussed. The ohmic loss increased when the ceria content was higher than 30 mol%. Even though the electrical conductivity of the anode decreased with increasing ceria content in the anode catalyst in association with decreasing nickel content, the ohmic loss was kept low until the ceria content was ≤30 mol% because the semiconducting ceria compensated for the decreased current path owing to the decreasing nickel content. The lowest activation loss was observed when the ceria content in the nickel anode catalyst was 30 mol% and the maximum activation loss was obtained for ceria content of 2 mol%. Ceria content in nickel anode influenced microstructure of the anode matrix. When the CeO2 content was 2 mol%, sintering of anode catalyst was evident and the porosity of anode matrix was almost 57% - highest in this study. Whereas sintering of anode catalyst was not evident and the porosity of anode matrix was 46% when the ceria content in the nickel anode catalyst was 30 mol%. Activation loss was strongly influenced by microstructure of anode matrix, and highest activation loss when the CeO2 content was 2 mol% was owing to the inappropriate microstructure for electrochemical reaction: sintering of the anode catalyst and excessive porosity of the anode. •Effect of ceria content in anode catalyst on discharge performance is investigated.•Ceria compensates for the current path in the anode.•The best discharge performance is obtained when the CeO2 content is 30 mol %.•Addition of 10 mol% ceria in nickel catalyst is effective to suppress sintering.•The discharge performance degrades by sintering of catalyst and excessive porosity.