Self-Assembled Triple-Conducting Nanocomposite as a Superior Protonic Ceramic Fuel Cell Cathode

Here, we report an oxygen ion-proton-electron-conducting nanocomposite, BaCo0.7(Ce0.8Y0.2)(0.3)O3-delta(BCCY), derived from a self-assembly process, as a high-performance protonic ceramic fuel cell (PCFC) or mixed O2-/H+ dual-ion conducting fuel cell (dual-ion FC) cathode. Self-assembly during high-temperature calcinations results in the formation of a nanocomposite consisting of a mixed H+/e(-) conducting BaCexYyCozO3-delta (P-BCCY) phase and mixed O2-/e(-) conducting BaCoxCeyYzO3-delta(M-BCCY) and BaCoO3-delta(BC) phases. The interplay between these phases promotes the oxygen reduction reaction (ORR) kinetics of this composite cathode and improves its thermo-mechanical compatibility by tempering the mismatch in thermal expansion coefficient (TEC). When tested as the cathode in anode-supported dualion FCs and PCFCs, peak power densities (PPDs) of 985 and 464 mW cm(-2), respectively, are achieved at 650 degrees C while maintaining a robust operational stability of 812 h at 550 degrees C. This material is ideally suited for high-performance cathodes for PCFCs and dual-ion FCs, greatly accelerating the commercialization of this technology.