Vanadium-assisted surface engineering of heterostructured cathode for enhanced protonic ceramic fuel cell performance

Enhancing the oxygen reduction kinetics at the cathode surface is crucial in the design optimization efforts for protonic ceramic fuel cells (PCFCs). Our study introduces a surface engineering strategy based on acid oxide-induced self-assembly to precisely control atomic arrangements on the surface of praseodymium-barium-cobalt ferrite (Pr_0.5Ba_0.5Co_0.7Fe_0.3O_3-δ, PBCF). This method enables the preparation of a “sandwich” type core-shell structure composed of three components: PBCF @Ba_vac(Barium Vacancies)@BaVO₃. The lattice oxygen redox activity of cathode was accordingly fine-tuned to enhance the cathode performance of PCFCs. The synergistic integration of surface BaVO₃ nanoparticles and Ba_vac enhanced the PCFC's power density by over 50 %, achieving 1.68 W cm⁻² at 650 °C. Furthermore, the formation of a barium vanadate second phase on the surface of PBCF not only aids in the redox reaction of the cathode but also significantly improves the stability of the cathode, thereby extending its lifetime. This research has broad applicability for surface modification of structurally stable perovskite cathodes.