Overcoming chromium poisoning in solid oxide cells through multiscale perovskite engineering

Chromium poisoning and sluggish oxygen kinetics limit oxygen electrodes in reversible solid oxide cells. We introduce a triple barrier design that integrates lattice stabilization by Ba to suppress SrO segregation, BaCoO3 nanodomains that trap chromium, and surface acidity tuning via trace Mo at the B site in La0.6Sr0.1Ba0.35Co0.2Fe0.78Mo0.02O3₋δ. The electrode reaches 0.058 Ω·cm2 polarization resistance at 750 °C, 70.4 percent lower than LSCF, delivers 1.352 W·cm⁻2 at 800 °C, and 2.08 A·cm⁻2 at 1.5 V. Under 0.5 A·cm⁻2 with a chromium source, single cells operate stably for about 1000 hours. Quantitative characterization and thermodynamic analysis show suppressed SrCrO4 formation and shallow chromium ingress, consistent with BaCoO3 mediated trapping and Mo moderated surface basicity. Density functional theory at operating temperature and pressure indicates Ba and Mo together weaken CrO3 adsorption. The design reconciles high activity with chromium tolerance and is transferable to related oxygen electrodes. Chromium poisoning and sluggish oxygen kinetics limit oxygen electrodes in reversible solid oxide cells. Here, the authors report a triple-barrier perovskite that suppresses Sr segregation, traps chromium, and tunes surface chemistry, enabling strong chromium tolerance and long-term stability.