Tailoring the cathode–electrolyte interface with nanoparticles for boosting the solid oxide fuel cell performance of chemically stable proton-conducting electrolytes

Solid oxide fuel cells (SOFCs) represent the most efficient devices for producing electrical power from fuels. The limit in their application is due to the high operation temperature of conventional SOFC materials. Progress is made toward lower operating temperatures using alternative oxygen-ion conducting electrolytes, but problems of stability and electronic conductivity still remain. A promising alternative is the use of chemically stable proton-conducting Y-doped BaZrO3 (BZY) electrolytes, but their practical applications are limited by the BZY's relatively low performance. Herein, it is reported that deposition by impregnation of cathode nanoparticles on BZY backbones provides a powerful strategy to improve the BZY-based SOFC performance below 600 °C, allowing an outstanding power output for this chemically stable electrolyte. Moreover, it is demonstrated that keeping the nanostructure is more important than keeping the desired chemical composition. The proposed scalable processing method can make BZY a competitive electrolyte for SOFC applications.