Engineering anion defect in perovskite oxyfluoride cathodes enables proton involved oxygen reduction reaction for protonic ceramic fuel cells

Endowed with high energy efficiency and low emission, protonic ceramic fuel cells (PCFCs) are emerging as sustainable energy converters at intermediate temperatures. However, the sluggish kinetics of proton involved oxygen reduction reaction (P-ORR) severely limits the commercial application of PCFCs. Herein, we highlight a novel anion defect engineered PrBa0.5Sr0.5Co1.5Fe0.5O5.84-δF0.16 (16F-PBSCF) perovskite oxyfluoride as a potential single-phase cathode towards PCFCs. It is revealed that F incorporation not only improves oxygen reduction kinetics but also accelerates water incorporation kinetics, ultimately resulting in high electrocatalytic performance. As a proof of concept, the PCFCs with 16F-PBSCF cathode delivers a high peak power density of 0.51 W cm−2 at 600 °C, superior to the PCFCs using pristine PBSCF cathode. These findings disclose that tailoring anion defect in perovskite oxyfluorides is a feasible approach to boost the P-ORR of cathode materials for PCFCs.