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

This paper presents a high-performance interconnect ceramic for solid oxide fuel cells (SOFCs), based on a modification of La0.7Ca0.3CrO3−δ (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 + 3 wt.% YDC, the electrical conductivity reached 104.8 S cm−1 at 800 °C in air. The electrical conductivity of the specimen with 2 wt.% YDC in H2 at 800 °C was 5.9 S cm−1. With the increase of YDC content, the relative density increased, reaching 97.6% when the YDC content was 10 wt.%. The average coefficient of thermal expansion (CTE) at 30–1000 °C in air increased with YDC content, ranging from 11.12 × 10−6 K−1 to 15.34 × 10−6 K−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.