Enhancing Oxygen Reduction Kinetics and Proton Transfer of La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ Cathode through Pr₂Ni_0.5Co_0.5O_4−δ Impregnation for Protonic Ceramic Fuel Cells

Sluggish reaction kinetics in oxygen reduction reaction (ORR) is one of the most important challenges to the development of protonic ceramic fuel cells (PCFCs). La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ (LSCF) exhibits high mixed ionic–electronic conductivity in traditional solid oxide fuel cells, but their slow proton transfer and ORR kinetics impedes practical applications. Herein, composite Pr₂Ni_0.5Co_0.5O_4−δ (PNC) particles composed of a perovskite PrNi_0.5Co_0.5O_3−δ phase and a PrO₂ phase are impregnated into a LSCF cathode to enhance the ORR activity and proton transfer. The polarization tested in a symmetric cell with PNC-impregnated LSCF cathode is 0.06 Ω cm² at 700 °C. The fuel cell with this impregnated cathode shows maximum power densities of 1857 mW cm⁻² at 700 °C. Moreover, the impregnated cathode exhibits a low degradation rate in the durability test. This work not only provides a novel and practical approach to improving the performance of current cathode materials for PCFCs but also highlights the potential for enhancing the commercial viability of PCFC technology.