High-Entropy Spinel Oxide Nanostructures as Stable Cathodes for Solid Oxide Fuel Cells

Solid oxide fuel cells (SOFCs) represent a promising clean energy technology for efficient chemical-to-electrical energy conversion with minimal environmental impact. However, the development of cathode materials that can maintain both high performance and long-term stability remains challenging, particularly due to the degradation of nanostructured cathodes caused by particle coarsening. This study employs an impregnation method to fabricate high-entropy spinel oxide (Mg0.2Fe0.2Co0.2Ni0.2Cu0.2)Fe2O4 (MFCNCF) nanoparticles with varying loadings on a porous Ce0.9Gd0.1O1.95 (GDC) skeleton. The optimized cathode with 30 wt % MFCNCF loading achieves a remarkably low polarization resistance of 0.12 Ω·cm2 and maximum power density of 1063.94 mW·cm-2 at 800 °C. Most significantly, the entropy stabilization effect enables the high-entropy spinel oxide nanoparticles to maintain their microstructure throughout 240 h of operation with negligible performance degradation. The study introduces a novel strategy combining high-entropy design with nanostructure engineering to develop stable and high-performance cathode materials for SOFCs.