Oxygen Reduction Activity Enhancement of Solid Oxide Fuel Cell Cathode via a Tiny Amount of Ni Doping

Abstract The predictable consequences of pollution and global warming force the attention to focus on clean and sustainable energy devices like solid oxide fuel cells (SOFCs). One crucial component of SOFCs is the advanced cathode material with excellent oxygen reduction reaction (ORR) activity and outstanding operating stability. Herein, a novel Ni‐doped cathode material with a detailed composition of Pr _0.5 Ba _0.4 Ca _0.1 Co _1‐x Ni _x O _3‐δ (PBCCNi _x , x = 0, 0.0125, 0.025) is successfully synthesized and evaluated. The unconventionally low Ni doping amount optimizes the oxygen defects on PBCCNi _0.0125 , enhancing the oxygen surface absorption and ORR activity. Among the cathodes investigated in this study, PBCCNi _0.0125 exhibits the best catalytic ORR activity, showing a low area‐specific resistance of 0.0152 Ω cm ⁻² at 800 °C. Ultimately, a single cell with PBCCN _0.0125 shows a peak power density of 1.72 W cm ⁻² , compared to that of 1.29 W cm ⁻² for the cell with PBCC without Ni doping. Besides, better stability of PBCCNi _0.0125 cathode on SOFCs operation conditions is also testified on a 200 h operating test. The optimization of oxygen defect concentration on PBCCNi _0.0125 would be a possible explanation for the performance enhancement, indicating that PBCCNi _0.0125 is a promising cathode material.