Atomic Layer Deposition Functionalized Composite SOFC Cathode La_0.6Sr_0.4Fe_0.8Co_0.2O_3-δ -Gd_0.2Ce_0.8O_1.9: Enhanced Long-Term Stability

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 ZrO 2 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-ZrO 2 overcoats are attributed to the performance retention observed for the overcoated cathode.