Chromium tolerance of high entropy BaO impregnated-(La_0.2Pr_0.2Sm_0.2Gd_0.2Nd_0.2)Ba_0.5Sr_0.5Co_1.5Fe_0.5O₅(LPSGNBSCF) cathodes for solid oxide fuel cell

The development of high-performance and chromium-tolerant stable hierarchical cathodes is crucial for practical applications of solid oxide fuel cells (SOFCs). This work presents a synergistic strategy to manufacture hierarchical cathodes, focusing on optimizing microstructural and electrochemical properties. By integrating advanced fabrication techniques, including nanostructuring and surface engineering, we achieved a significant enhancement in high entropy double perovskite cathode. The electrochemical activities and chromium tolerance of BaO impregnated on (La_0.2Pr_0.2Sm_0.2Gd_0.2Nd_0.2)Ba_0.5Sr_0.5Co_1.5Fe_0.5O₅ (LPSGNBSCF) high-entropy double perovskite cathodes in SOFCs were investigated in this study. Here, an optimum coated amount of BaO-LPSGNBSCF-0.15 mol/L electrode exhibited smaller electrode polarization resistance (R_p) of 0.22 Ω cm² than pure LPSGNBSCF electrode with R_p of 0.5 Ω cm² operating at 800 °C in the presence of Cr₂O₃ for 100 h. The synergistic catalyst coating of BaO-LPSGNBSCF-0.15 M could lead to less Cr deposition and SrCrO₄ formation on LPSGNBSCF after exposure to Cr₂O₃. Moreover, the cell delivered the maximum power density of 985.9 mW/cm² at 800 °C, higher than 803.1 mW/cm² of bare LPSGNBSCF single cell and showed good stability with 100 h in short-term test. This work elucidated a rational design of efficient and durable high-entropy-based chromium tolerant cathode for SOFCs.