Preparation and performance of cathode materials for Protonic Ceramic Fuel Cells

Protonic ceramic fuel cells (PCFCs) stand out as a novel energy conversion device, exhibiting unique advantages in terms of both high efficiency and environmental friendliness. However, PCFC cathodes are often underperforming due to their incapability to balance the electronic, oxygen-ionic, and protonic conductions involved in the oxygen reduction reactions. In this work, a series of BaCo0.6Fe0.4-xTixFyO3-y-δ (x=0.05, 0.1, 0.2, y=0, 0.1) perovskite oxides were prepared as a platform to demonstrate the synergy effect of cation-anion co-doping in regulating the triple conduction (electron, oxygen ion, and proton). Our experiments reveal that the co-doping of Ti4+ and F- can promotively generate an elevated level of oxygen vacancies and proton defects, thereby enhancing the transport rates of both oxygen ions and protons and thus achieving a significant improvement in electrochemical performance. Specifically, the polarization impedance of the BCFTF material is measured to be only 0.12 ω•cm2 at 650°C, and its peak power density in a PCFC cathode reaches 0.81 W cm-2. Our work may provide an innovative method to design an excellent-performance PCFC cathode.