Electrolyte evolution: The impact of indium doping on BaCe0.9Gd0.1O3-δ

BaCe 0.9-x In x Gd 0.1 O 3-δ (where x = 0.1, 0.2, 0.3, 0.4) electrolytes were successfully synthesized via the solid-state reaction (SSR) method. The structure was analyzed through X-ray diffraction (XRD), scanning electron microscopy (SEM), and XRD refinement techniques. The oxidation states of cerium and the presence of oxygen vacancies were investigated with X-ray photoelectron spectroscopy (XPS). Electrical conductivity was evaluated using electrochemical impedance measurements conducted over a temperature range of 500 °C–650 °C in various atmospheres. The electrical properties demonstrate that BaCe 0.6 In 0.3 Gd 0.1 O 3-δ exhibits outstanding performance. XRD, SEM, and cell refinement confirm that BaCe 0.6 In 0.3 Gd 0.1 O 3-δ exhibits a cubic perovskite structure within the space group Pm-3m, with relative densities exceeding 97 % and showing remarkable chemical stability for 108 days in air. The highest conductivity of BaCe 0.6 In 0.3 Gd 0.1 O 3-δ , recorded at 7.24 mS cm −1 in dry hydrogen at 600 °C, establishes it as a promising alternative for solid oxide fuel cell (SOFC) electrolytes, particularly for lowering operating temperatures.