Alternative materials for solid oxide fuel cells: Processing and interactions of materials.

摘要

The purpose of this research is to develop alternative materials for solid oxide fuel cell (SOFC) interconnections and electrodes with improved electrical, thermal, and electrochemical properties. The overall approach for this research and development is to: minimize the number of cations in the electrode, electrolyte, and interconnection by developing yttrium compounds, such as Y(Ca)CrO(sub 3) as the interconnection, and Y(M(prime))MnO(sub 3) as the air electrode; develop advanced synthesis and fabrication processes for air sintering, below 1,500 C, of chromite interconnections through (1) the use of sintering aids; and (2) the synthesis of submicrometer powders; establish methods for the simultaneous processing and consolidation of air-sinterable powders; electrochemically evaluate interface reactions (in reproducible and controlled laboratory tests) for both the alternate and state-of-the-art materials and cell components developed under this program; and evaluate the chemical reactivity and interdiffusion effects that take place between the various fuel cell components: electrolyte/cathode, interconnect/cathode, and interconnect/anode. This paper describes a comprehensive study that assessed the processing of air-sinterable chromites, the sintering mechanism of chromites, and the chemical reactivity and interdiffusional effects between the interconnect, air, and fuel electrodes. Materials evaluated were La(sub 0.7)Ca(sub 0.31)CrO(sub 3), La(sub 0.7)Ca(sub 0.29)CrO(sub 3), (Y(sub 0.6)Ca(sub 0.4))(sub 1.05)Cr(sub 0.95)O(sub 3), La(sub 1(minus)x)Sr(sub x)MnO(sub 3), La(sub 1(minus)x)Ca(sub x)MnO(sub 3), Y(sub 1(minus)x)Ca(sub x)MnO(sub 3), and Y(sub 1(minus)x)Sr(sub x)MnO(sub 3).