Spatial investigation of electronic properties in composite electrolytes for solid oxide fuel cells using embedded probes

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>Local electronic conduction is spatially investigated through two types of co-ionic conducting composite electrolytes, BCY15 (BaCe<SUB>0.85</SUB>Y<SUB>0.15</SUB>O<SUB>3-d</SUB>) - GDC20 (Gd<SUB>0.2</SUB>Ce<SUB>0.8</SUB>O<SUB>2-d</SUB>) and BZY15 (BaZr<SUB>0.85</SUB>Y<SUB>0.15</SUB>O<SUB>3-d</SUB>) - NDC10 (Nd<SUB>0.1</SUB>Ce<SUB>0.9</SUB>O<SUB>2-d</SUB>), to understand their durability under abnormal operating conditions. Electrical potential variation is measured through the electrolytes using embedded Pt probes under open circuit conditions, from which we find that an effective electrolyte region (with high electronic resistance) is expanded in both composite electrolytes, in comparison with doped ceria (single phase) electrolyte. In BCY15-GDC20, most of the electrolyte region shows high electronic resistance, except for the region close to the anode. A contrast tendency is observed in BZY15-NDC10 showing mixed conduction in the region close to the cathode. Both types of composite electrolytes degrade under negative voltage conditions, but they are stable under positive voltage conditions. Post-analysis reveals that electrode/electrolyte delamination occurs at the cathode side in BCY15-GDC20 while it occurs at the anode side in BZY15-NDC10. Thus, we can say that the local electronic properties of composite electrolytes determine their stability, and the high electronic resistance region is vulnerable when the cell is subjected to abnormal conditions such as negative cell voltages.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Anode supported BCY15-GDC20 and BZY15-NDC10 cells were fabricated. </LI> <LI> Local electronic conduction was spatially investigated using embedded probes. </LI> <LI> Local electronic properties determined the composite electrolytes' stability. </LI> <LI> High electronic resistance region was vulnerable under negative voltage conditions. </LI> </UL> </P>