Highly Efficient A- and B-Site-Doped Ruddlesden–Popper Perovskite Oxide Nd2–xSrxNi0.9Cu0.1O4+δ as a Cathode for PCFCs

At medium and low operating temperatures, the slow reaction kinetics of the cathode is a significant limiting factor hindering proton ceramic fuel cell (PCFC) development. This work reports a Nd2–xSrxNi0.9Cu0.1O4+δ (x = 0, 0.2, 0.4, 0.6, 0.8, 1) Ruddlesden–Popper cathode through a combination strategy of A-site Sr2+ and B-site Cu2+ codoping. Appropriate Sr2+ doping has achieved the synergistic optimization of conductivity and electrocatalytic activity by modulating the amount of surface oxygen defects and the valence state of B-site Ni2+. Nd1.4Sr0.6Ni0.9Cu0.1O4+δ (NSNC6) exhibits a remarkably improved conductivity (exceeding 100 S cm–1 from 450 to 750 °C) and an enhanced electrocatalytic activity. The PCFC with the NSNC6-BZCNY triple-conducting cathode exhibits sufficient long-term stability and a maximum power density of 445 mW cm–2 at 650 °C, which is approximately 50% higher than that of the PCFC with the NSNC6 cathode, highlighting its potential as a cathode material for PCFCs.