Heterogeneous Catalyst Coating for Boosting the Activity and Chromium Tolerance of Cathodes for Solid Oxide Fuel Cells

Abstract A challenge hindering the development of durable solid oxide fuel cells (SOFCs) is the significant performance degradation of cathodes owing to poisoning by volatile Cr originating from the Fe─Cr alloy interconnect. Herein, a heterogeneous catalyst coating, composed of Ba_1−xCe_0.8Gd_0.2O_3–δ and BaCO₃, remarkably improves the oxygen adsorption, dissociation capability, and Cr resistance of a La_0.6Sr_0.4Co_0.2Fe_0.8O_3–δ (LSCF) cathode is demonstrated. The coherent heterointerface interactions formed between the catalyst coating and LSCF result in varied levels of surface strain and electrostatic interactions, significantly suppressing Sr surface segregation on LSCF. A single cell with the catalyst coating‐decorated LSCF (CC‐LSCF) achieves a peak power density of 1.73 W cm⁻² at 750 °C, with no noticeable performance degradation for 100 h. The CC‐LSCF cathode also exhibits outstanding durability under accelerated Cr poisoning conditions, compared with the tremendous degradation rate of 0.42% h⁻¹ for the bare LSCF cathode. The enhanced Cr resistance is attributed to synergy induced by the stabilization of the lattice Sr cations by heterointerface interactions and the remarkable structural stability of the catalyst coating under Cr poisoning conditions. The novel heterointerface engineering strategy in this study provides insight into the design and development of active and Cr‐tolerant cathodes.