Electrical properties, sintering and thermal expansion behavior of composite ceramic interconnecting materials, La0.7Ca0.3CrO3-δ/Y0.2Ce0.8O1.9 for SOFCs

• Published in: Acta materialia 2007-04, Vol.55 (6), p.2113-2118
• Main Authors: Zhou, Xiaoliang, Zhu, Mingxing, Deng, Feijun, Meng, Guangyao, Liu, Xingqin
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Metals. Metallurgy; Powder metallurgy. Composite materials; Production techniques; Sintered metals and alloys. Pseudo alloys. Cermets
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/j.actamat.2006.10.059

This paper presents a high-performance interconnect ceramic for solid oxide fuel cells (SOFCs), based on a modification of La0.7Ca0.3CrO3-delta (LCC). It was found that addition of a small amount of YDC (Y0.2Ce0.8O1.9) into LCC dramatically increased the electrical conductivity. For the best system, LCC+3wt.% YDC, the electrical conductivity reached 104.8Scm-1 at 800 deg C in air. The electrical conductivity of the specimen with 2wt.% YDC in H2 at 800 deg C was 5.9Scm-1. With the increase of YDC content, the relative density increased, reaching 97.6% when the YDC content was 10wt.%. The average coefficient of thermal expansion (CTE) at 30-1000 deg C in air increased with YDC content, ranging from 11.12X10-6K-1 to 15.34X10-6K-1. The oxygen permeation measurement illustrated a negligible oxygen ionic conduction, indicating that it is still an electronically conducting ceramic. Therefore, it is a very promising interconnecting ceramic for SOFCs.