Interaction between chromia forming alloy interconnects and air electrode of solid oxide fuel cells

Abstract

The performance of solid oxide fuel cells, especially on the air side, degrades very rapidly when chromia forming alloys are used as interconnects in contact with electrodes. The effect of chromia forming alloys on the performance of doped LaMnO₃ air electrode has been studied at the current fuel cell operating temperatures in the vicinity of 900–1000 °C. Interactions between a chromium-rich alloy and doped LaMnO₃ were studied during testing of fuel cell stacks as well as in specially designed electrochemical experiments. On completion of these experiments interconnect/electrode and electrode/ electrolyte interfaces as well as interconnect, electrode and electrolyte materials were examined with scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and optical microscopy. A mechanism for cell performance degradation based on these observations has been proposed.