Fabrication of BaZr _0.1 Ce _0.7 Y _0.1 Yb _0.1 O _3‐δ Skeleton Structure for the Development of High‐Performance Nanocomposite Cathodes for Protonic Ceramic Fuel Cells by Nitrate Impregnation

ABSTRACT A stable and interconnected skeleton structure is critical for the fabrication of high‐performance nanocomposite cathodes by impregnation for protonic ceramic cells (PCCs). This work systematically synthesizes an interconnected BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3‐δ (BZCYYb1711) electrolyte skeleton structure on a dense BZCYYb1711 electrolyte and introduces three catalytic active materials by nitrate impregnation: the electronic conducting La 0.8 Sr 0.2 MnO 3‐δ (LSM), mixed ionic and electronic conducting La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3‐δ (LSCF) and triple conducting PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ (PBSCF). The results indicate that skeleton formation and interconnectivity are strongly associated with sintering temperature, most likely governed by the thermodynamics of densification of Ba‐containing electrolyte ceramics. The electrode performance strongly correlates with the activity of the impregnated oxides. The PBSCF impregnated BZCYYb1711 (PBSCF‐1711) electrode exhibits the best performance with a low R p value of 0.06 Ω cm 2 at 700°C in wet air. The fuel cell with PBSCF‐1711 cathode shows a maximum power density of 486 mW cm −2 at 700°C and demonstrates excellent durability, operating stably for over 700 h in fuel cell (FC) mode and through cyclic fuel cell/electrolysis cell operation at 0.5 A cm −2 in H 2 /wet air for 100 h. This study shows the potential for the development of high‐performance air electrodes on a stable and interconnected porous skeleton structure based on nitrate impregnation for PCCs.