Novel composite interconnecting ceramics La0.7Ca0.3CrO3−δ/Ce0.8Sm0.2O1.9 for solid oxide fuel cells

In this paper, an interconnecting ceramic for solid oxide fuel cells was developed, based on the modification from La0.7Ca0.3CrO3−δ by addition of Ce0.8Sm0.2O1.9. It is found that addition of small amount Ce0.8Sm0.2O1.9 into La0.7Ca0.3CrO3−δ dramatically increased the electrical conductivity. For the best system, La0.7Ca0.3CrO3−δ + 5 wt.% Ce0.8Sm0.2O1.9, the electrical conductivity reached 687.8 S cm−1 at 800 °C in air. In H2 at 800 °C, the specimen with 3 wt.% Ce0.8Sm0.2O1.9 had the maximal electrical conductivity of 7.1 S cm−1. With the increase of Ce0.8Sm0.2O1.9 content the relative density increased, reaching 98.7% when the Ce0.8Sm0.2O1.9 content was 10 wt.%. The average coefficient of thermal expansion at 30–1000 °C in air increased with Ce0.8Sm0.2O1.9 content, ranging from 11.12 × 10−6 to 12.46 × 10−6 K−1. The oxygen permeation measurement illustrated a negligible oxygen ionic conduction, indicating it is still an electronically conducting ceramic. Therefore, this material system will be a very promising interconnect for solid oxide fuel cells.