Enhanced resistance of gadolinium-doped cerium oxide to liquid antimony and antimony oxide corrosions by addition of iron oxide

Abstract

To increase corrosion resistance of gadolinium-doped cerium oxide (GDC) electrolytes for direct carbon solid oxide fuel cells with liquid Sb anodes, GDC-based electrolytes with Fe2O3 addition of 1 (GDCF-1), 2 (GDCF-2) and 3 (GDCF-3) mol.% have been prepared and evaluated chemically and electrochemically in contact with liquid Sb and Sb2O3 at 750 °C for 100 h. The results show that Fe2O3 addition significantly increases the resistance of the electrolytes to the chemical corrosion by liquid Sb, and GDCF-2 demonstrates the highest resistance with a corrosion affected thickness of about 60 μm, which is smaller than 1/8 of that of GDC. What's more, the affected thickness is only about 4 μm for GDCF-2 in contact with liquid Sb2O3. Under a current density of 100 mA cm−2 with liquid Sb as anode, the cell voltage almost increases linearly and cell ohmic resistance decreases in the 100 h's operation. The performance promotion is resulted from the reduction of GDCF-2 thickness caused by liquid Sb/Sb2O3 corrosion, but the total thickness reduction is about 200 μm, which is only 2/5 of that of GDC.