An innovative and facile synthesis route of (La,Sr) ₂FeO _{4+ δ} –La _0.4Sr _0.6FeO _{3− δ} composite as a highly stable air electrode for reversible solid oxide cell applications

Achieving thermal cycle stability is an imperative challenge for the successful commercialization of solid oxide cells (SOC) technology. Ruddlesden-Popper (R-P) oxides, with their thermal expansion coefficient (TEC) compatible with common electrolytes, are promising candidates for SOC applications. However, the two-dimensional conduction characteristic of R-P oxides leads to insufficient catalytic activity, which hinders their performance. Here, we proposed a win-win strategy of self-assembly decoration, employing a one-pot method to address this issue. By using the single perovskite oxide (La_0.4Sr_0.6FeO₃) to modify the R-P oxide (La_0.8Sr_1.2FeO_4+δ), we enhance the electrochemistry performance without compromising the stability of the composite electrode. The strategic incorporation of 10 mol% perovskite phase at 800 °C resulted in a significant 49% reduction in polarization resistance, an impressive 86% increase in maximum power density under power generation mode, and a notable 33% increase in electrolysis current density under electrolysis mode. Furthermore, the perovskite-decorated R-P oxide composite also exhibit high thermal and chemical stability, with negligible performance degradation observed under both thermal cycling and charge/discharge cycling conditions. Our results demonstrate that such dual-phase composite, which is simultaneously produced by one-step process, with outstanding catalytic activity and stability can be considered an effective strategy for the advancement of solid oxide cell.