Application of GDC-YDB bilayer and LSM-YDB cathode for intermediate temperature solid oxide fuel cells

Abstract

Yttria-doped bismuth (YDB) and gadolinia-doped ceria (GDC) are investigated as a bilayer electrolyte for intermediate temperature solid oxide fuel cells (IT-SOFCs). LSM-YDB is used as a cathode material in order to improve the poor ionic conduction of LSM and the compatibility with the YDB electrolyte. The performance of the bilayer cell was measured under humidified H-2 (3 % H2O) atmosphere and an operating temperature between 500 A degrees C and 650 A degrees C. The polarization resistance and ohmic resistance of the GDC-YDB bilayer cell were 0.189 a"broken vertical bar cm(2) and 0.227 a"broken vertical bar cm(2) at 650 A degrees C, respectively. The bilayer cell showed 0.527 Wcm(-2) in the maximum power density at 650 A degrees C, which is about two times higher than the single-layer cell of 0.21 Wcm(-2). The OCV of the bilayer cell was 0.89 V at 650 A degrees C, suggesting that the electronic conduction caused by the reduction of ceria was successfully suppressed by the YDB layer. The introduction of an YDB-GDC bilayer cell with LSM-YDB cathode thus appears to be a promising method for improving the performance of GDC-based SOFCs and reducing operating temperature.