Atomic Layer Deposition Functionalized Composite SOFC Cathode La_(0.6)Sr_(0.4)Fe_(0.8)Co_(0.2)O_(3-δ) -Gd_(0.2)Ce_(0.8)O_(1.9): Enhanced Long-Term Stability

摘要

We report that the long-term stability of a conventional mixed oxide-ion and electron conducting solid oxide fuel cell cathode, La_(0.6)Sr_(0.4)Fe_(0.8)Co_(0.2)O_(3-δ) -Gd_(0.2)Ce_(0.8)O_(1.9) (LSCF-GDC) composite, can be markedly improved by functionalizing its surfaces with a conformal layer of nanoscale ZrO2 films through atomic layer deposition (ALD). Over a >1100 h testing at 800 °C, the overcoated LSCF-GDC cathode exhibited respective polarization and ohmic area-specific-resistances 3 and 1.5 times lower than the pristine sample, whereas the pristine LSCF-GDC cathode degraded at a rate 4 times faster than the overcoated one. The multifunctionality of porosity, mixed conductivity, and suppressed Sr-enrichment enabled by the nanoscaled ALD-ZrO2 overcoats are attributed to the performance retention observed for the overcoated cathode.