Enhanced performance and stability of perovskite through composition and phase regulation as cathode for protonic ceramic fuel cell

Protonic ceramic fuel cells (PCFCs) offer promising solutions for efficient and flexible energy conversion at intermediate temperatures (300–700 °C), addressing critical challenges of material degradation and high operational costs in solid oxide fuel cells. However, the development of cathode materials with enhanced proton conductivity, oxygen reduction reaction (ORR) activity, and long-term stability remains an imminent challenge. PrBaB 2 O 5 (B = transition metal) double perovskites oxides (DPOs) materials have emerged as high-potential alternatives due to the superior catalytic activity, high oxygen vacancy concentration, and good electronic conductivity at intermediate temperatures. Here, the PrBa 0.8 Ca 0.2 Fe 2-x Co x O 5+δ DPOs structure was designed with ordered arrangement of Pr and Ba cations. By adjusting the Fe/Co ratio in B-site, a transition from a simple cubic structure to a double perovskite structure was successfully achieved. The synthesized PrBa 0.8 Ca 0.2 Fe 0.4 Co 1.6 O 5+δ (PBCX-16) with a double-perovskite structure demonstrates exceptional performance, including a peak power density of 1.511 W cm −2 at 700 °C and a remarkably low polarization impedance of 0.068 Ω cm 2 . Furthermore, the cell with PBCX-16 cathode can stably operate for up to 250 h at 600 °C. This work offers the innovative insights into the structural modulation of cathode materials and advances the development of cathodes for PCFCs.