Ultrafast Sintered Composite Cathode Incorporating a Negative Thermal Expansion Material for High-Performance Protonic Ceramic Fuel Cells

Protonic ceramic fuel cells (PCFCs) offer a promising, clean, and efficient energy conversion solution. However, thermal mismatch between cathodes and electrolytes remains a critical obstacle, leading to interfacial damage such as cracking and delamination. Incorporating negative thermal expansion (NTE) materials into the cathode can mitigate this issue. The challenge lies in integrating NTE materials without compromising electrochemical performance or causing unwanted reactions during sintering. This study introduces a novel BaFe_0.9Zr_0.1O_3-δ (BFZ)-NdMnO_3-δ composite cathode fabricated using an ultrafast high-temperature sintering (UHS) process. This approach mitigates thermal expansion while boosting the cathode's catalytic activity compared to a single-phase BFZ cathode. The resulting fuel cell achieves a high peak power density of ∼550 mW cm^-2 at 600 °C and demonstrates excellent stability during a 100 h test at 550 °C. These findings highlight the potential of UHS for developing high-performance, thermally compatible cathode materials that advance the field of PCFCs.