Electrical and microstructural characterization of Gd-doped Ceria/Y-doped Zirconia bi-layer electrolyte prepared by tape casting

Abstract

GDC-YSZ bi-layer SOFC electrolytes are an interesting manner to protect GDC electrolytes of the low oxygen
partial pressure present at anode-electrolyte interface. This oxygen partial pressure condition and high
temperatures during the operation of SOFC permit GDC electrolyte reduction injuring the performance of
SOFC. In this work, GDC-YSZ bi-layer electrolytes were prepared using double tape casting technique. Single
layers of YSZ and GDC electrolytes were also prepared by the same technique for comparison. All samples
were sintered at 1600 °C/2 h in air and analyzed by SEM and impedance spectroscopy technique. A
good adhesion was established between the layer GDC and YSZ and no cracks were detected despite the differential
firing shrinkage. The electrical conductivity of GDC-YSZ bi-layer sample at 350 °C was 7.98x10-5
S.cm-1 and for GDC and YSZ single layer samples electrical conductivities were 1.89x10-4 S.cm-1 and
4.71x10-5 S.cm-1, respectively. These results show that GDC-YSZ bi-layer electrolyte is superior to YSZ single
layer electrolyte.