Halogen additive architectonics of Sm doped CeO2 electrolytes for effect on the electrical properties at low temperatures

Solid oxide electrolyte Sm doped CeO₂(SDC) materials have been extensively studied for their excellent properties in fuel cell applications. Although most research on SDC focuses on metal-oxygen ion conduction, relatively few studies have explored anion behavior. In this study, halogens (F, Cl, Br, I) were successfully incorporated into the SDC lattice, and their effects were analyzed in detail. Further electrochemical studies have shown that the high electronegativity of halogens effectively promotes the diffusion ability of oxygen ions in the lattice, thus enhancing the electrical conductivity. The ionic conductivity of F, Cl, and Br-doped SDC electrolytes is significantly higher in the temperature range of 475 to 550 °C compared to Br-doped SDC. Specifically, the power output of a single cell using Br-doped SDC reached 784 mW cm^− 2 at 550 °C, which is notably higher than that of a cell based on the undoped SDC electrolyte (583 mW cm^− 2). These findings offer new insights into the design of low-temperature solid oxide fuel cell electrolytes.