Enhanced Electrochemical Properties of Non-stoichiometric Layered Perovskites, Sm 1-x BaCo 2 O 5+d , for IT-SOFC Cathodes

• Published in: Frontiers in chemistry 2021, Vol.9, p.633868
• Main Authors: Kim, Chan Gyu, Woo, Sung Hun, Song, Kyeong Eun, Baek, Seung-Wook, Kang, Hyunil, Choi, Won Seok, Kim, Jung Hyun
• Format: Article
• Language: English
• ISSN: 2296-2646; 2296-2646

In this study, electrochemical properties of layered perovskites having non-stoichiometric compositions (Sm BaCo O , = 0, 0. 01, 0.02, 0.03, 0.04, 0.05, 0.10, and 0.15) were analyzed for the direct application of cathode materials for Intermediate Temperature-operating Solid Oxide Fuel Cells (IT-SOFC). From the Sm BaCo O oxide systems calcined at 1,100°C for 8 h, single phase (SmBaCo O , SBCO_1) was maintained only in the case of the = 0 composition. In the compositions of = 0.05-0.10, BaCoO was mixed with the pattern of SBCO. In addition, in the composition of = 0.15, it was confirmed that BaCoO and CoO phases coexisted with SBCO. In the compositions of Sm BaCo O , the overall Area Specific Resistance (ASR) values decreased as the removal amount of Sm increased from = 0-0.10; then, the values increased for compositions from = 0.15. For example, the ASRs of SBCO_1, Sm BaCo O (SBCO_0.95), Sm BaCo O (SBCO_0.90), and Sm BaCo O (SBCO_0.85) measured at 600°C were 0.301, 0.147, 0.119, and 0.179 Ω cm , respectively. In particular, SBCO_0.90 was found to have an excellent ASR property of about 0.035 Ω cm at 700°C. Typical properties of the metal-insulator transition (MIT) electrical conductivity were shown in all measured compositions. The temperature at which MIT occurred increased as the non-stoichiometric composition increased.