A high-performance and stable Pr1.9Bi0.1Ni0.9Cu0.1O4+δ@BaZr0.1Ce0.7Y0.1Yb0.1O3 core-shell composite cathode for PCFCs

Ruddlesden - Popper (RP) structured PrNi 2 O 4+δ (PN) doped with Bi (Pr 1 . 9 Bi 0 . 1 NiO 4+ δ, PBN), Cu (Pr 2 Ni 0 . 9 Cu 0 . 1 O 4+ δ, PNC), and Bi/Cu (Pr 1 . 9 Bi 0 . 1 Ni 0 . 9 Cu 0 . 1 O 4+ δ, PBNC) is studied as a component in BaZr 0 . 1 Ce 0 . 7 Y 0 . 1 Yb 0 . 1 O 3 (BZCYYb) supported composite cathode for proton - conducting fuel cells (PCFCs). The BZCYYb scaffold transports protons, and the solution - impregnated RP coating conducts oxygen ions and electrons, enabling the cathode to exhibit the triple - conduction behavior required by PCFCs. The results indicate that the co-doped PBNC effectively reduces the phase formation temperature and enhances the catalytic activity of oxygen reduction reactions and performance stability. These improvements are attributed to its increased surface concentration of oxygen vacancy , which promotes the absorption and dissociation of water and oxygen, and thus surface hydration (protonation) reactions. With humidified hydrogen (3 % H 2 O) fuel and air oxidant, the single cell with the PBNC@BZCYYb core - shell cathode achieves a peak power density of 0.680 W cm −2 at 700 °C, around a 1 - time increase compared to that with the PN@BZCYYb cathode, and performs stably over 600 h at 0.5V and 650 °C. These findings demonstrate the potential of PBNC@BZCYYb as a high - performance cathode for medium and low temperature PCFC, providing new possibilities for efficient energy conversion. • Bi and Cu co-doping lowered Ruddlesden-Popper phase formation temperature for PBNC. • The PBNC@BZCYYb cell achieved 680 mW/cm 2 at 700 °C. • The PBNC@BZCYYb cell performed stably for 600 h at 650 °C.