Fe-Based Layered Double Perovskite Anode with in Situ Exsolved Nanoparticles for Direct Carbon Solid Oxide Fuel Cells

Direct carbon solid oxide fuel cells (DC-SOFCs), which can efficiently convert chemical energy of carbonaceous fuels into electricity, have recently gained much research attention as they offer an effective way to address future economic and environmental challenges. Herein, B-site Ti-substituted (PrBa)_0.95Fe_2-xTi_xO_6−δ (PBFT_x, x = 0-0.3) materials are synthesized via a sol-gel combustion method and evaluated as anode materials for DC-SOFCs. Ti doping enhances the phase structure stability of the material under a reducing atmosphere. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy analyses demonstrate the exsolution of metallic Fe nanoparticles on the surface of the PBFT_x perovskite lattice after the materials are treated under a reducing atmosphere, which can improve the catalytic performance of DC-SOFC anode. Among the Ti-doped samples (x = 0.1-0.3), PBFT_0.2 shows the largest adsorption capacity for CO and the highest electrical conductivity in air. Using pure nano-activated carbon as a fuel, the single cell supported by La_0.9Sr_0.1Ga_0.8Mg_0.2O₃ electrolyte with PBFT_0.2 as an anode achieves the maximum power densities of 527, 281, and 146 mW·cm^-2 at 800, 750, and 700 °C, respectively. The above excellent performance of PBFT_0.2 indicates that it has great potential for application in DC-SOFC anode.