Bismuth doped La0.5-xBixSr0.5Fe0.9Mo0.1O3-δ perovskite as high active oxygen electrode for solid oxide cells

Developing Fe-based high active and stable oxygen electrode materials is essential for commercializing solid oxide cells (SOC). Herein, La0.5-xBixSr0.5Fe0.9Mo0.1O3-δ (x = 0–0.3) oxides are synthesized and used as oxygen electrodes for oxygen reduction/evolution reaction (ORR/OER). Bi-doping at La-site significantly improves the ORR/OER activity, producing high cell performance in fuel cell and electrolysis modes. At 800 °C, the polarization resistance of La0.3Bi0.2Sr0.5Fe0.9Mo0.1O3-δ is only 0.09 Ω cm2, which is almost 3.5 times lower than undoped La0.5Sr0.5Fe0.9Mo0.1O3-δ electrode. Moreover, the Ni-YSZ-supported full cell delivers a peak power density of 1237 mW cm−2 in fuel cell mode and a current density of −2717 mA cm−2 @ 1.5 V in electrolysis mode. The electrolysis cell demonstrates an excellent durable operation for ∼130 h under 500 mA cm−2 and 750 °C. Therefore, the Bi doping strategy is effective for designing highly active oxygen electrodes of solid oxide cells.