Resolving Interfacial Incompatibility of La2NiO4+δ Cathodes with YSZ Electrolytes via SDC Backbone

Abstract

The integration of highly active cathode materials into yttria-stabilized zirconia (YSZ)-based solid oxide fuel cells (SOFCs) remains challenging due to interfacial instability and insufficient mechanical anchoring. Although La2NiO4+δ (LNO) offers fast oxygen transport and high oxygen reduction reaction (ORR) activity with relatively improved chemical compatibility with YSZ, its practical implementation is often limited by structural and interfacial degradation. In this study, a porous samarium-doped ceria (SDC) backbone was introduced as an interfacial engineering strategy to stabilize LNO cathodes on YSZ electrolytes. A uniform backbone architecture was fabricated via ultrasonic spray coating, and its sintering behavior and chemical compatibility were systematically investigated. Optimized sintering at 1000 oC provided a structurally robust yet highly porous backbone while suppressing interfacial reactions with YSZ. The incorporation of the SDC backbone significantly improved cathode–electrolyte interfacial integrity, as confirmed by cross-sectional analysis and peeling tests. Theses interfacial improvements resulted in markedly enhanced electrochemical performance, including significantly higher power densities and pronounced reductions in both ohmic and polarization resistances across the entire temperature range. This work demonstrates that backbone-assisted interfacial engineering enables stable integration of highly active cathode materials into YSZ-based SOFCs and provides a practical design strategy for next-generation high-performance electrode architectures.