Reconciling the Stability-Activity Dilemma on Perovskite Oxide Electrode Surfaces with Oxygen-Deficient ZrO _<i>x</i> Nanocoatings

Perovskite oxides are promising solid oxide cell electrodes, yet their long-term stability is limited by performance degradation driven by cation segregation at operating temperatures. Conventional doping strategies to mitigate segregation compromise bulk transport properties or surface reaction kinetics by reducing oxygen-vacancy concentrations, representing an inherent trade-off between stability and activity. Here, a surface-specific strategy reconciles this dilemma by depositing an oxygen-deficient ZrOx nanocoating via atomic layer deposition (ALD) on Sr2Fe1.5Mo0.5O6−δ (SFMO) electrodes. This vacancy-rich ZrOx coating achieves dual-function simultaneously: (1) a high concentration of oxygen vacancies drives Sr2+ ions inward, while (2) self-forming Zr–O–Fe interlayers stabilize elastic and electrostatic force, effectively suppressing surface Sr accumulation. Furthermore, high oxygen deficiency maintains fast oxygen reaction kinetics. This nanocoating stabilizes SFMO electrodes at 800 °C for 50 h with minimal performance degradation, retaining the unsegregated SFMO electrode activity. This strategy provides generalizable routes for stabilizing perovskite oxide devices in high-temperature environments.