(Mn,Cu)_3O_4-based conductive coatings as effective barriers to high-temperature oxidation of metallic interconnects for solid oxide fuel cells

摘要

(Mn,Cu)_3O_4-based conductive oxides are examined as protective coatings to improve the surface stability of metallic interconnects for solid oxide fuel cells at high temperatures. Nano-sized Mn_(3?x)Cu_xO_4 materials with various Cu contents (x =1.0–1.5) are synthesized and a compositionstructure–property relationship is experimentally determined. The Cu content (x) has a significant influence on phase stability as well as sintering, electrical, and thermal expansion characteristics. Thin and dense Mn_(3?x)Cu_xO_4 coatings are fabricated on the interconnects (Crofer 22 APU) by a slurry coating process and subsequent heat treatment. The coated interconnects exhibit area-specific resistances as low as 7.1–15.0 mΩ cm~2 at 800 °C. The electrochemical cell shows no performance degradation in the presence of the Mn_(3?x)Cu_xO_4-coated interconnect. The results indicate that the Mn_(3?x)Cu_xO_4 coatings act as an effective barrier to high-temperature oxidation of the metallic interconnects.