Unlocking scandia stabilized zirconia: Aging suppression by ternary co-doping

This study aims to unlock the potential of ternary co-doping to mitigate the aging phenomena in scandia-stabilized zirconia (SSZs) while maintaining their intrinsic characteristics of ion conduction. Precisely, a strategic partial replacement of zirconia in the SSZ has been made with two different-sized cations, and its effect on atomic arrangement, electrical conductivity, and aging has been explored. The results revealed that (In₂O₃)_0.0025 (Yb₂O₃)_0.0025 (Sc₂O₃)_0.11 (ZrO₂)_0.885 (In-Yb11SSZ) had suppressed the aging of (Sc₂O₃)_0.11 (ZrO₂)_0.89 (11SSZ) by 44 % and 65 % in typical cathodic (air) and anodic (97 vol% H₂/3 vol% H₂O) conditions of solid oxide fuel cells (SOFCs) at 800 °C, with a remarkable ionic conductivity of 0.087 S/cm at 800 °C. Furthermore, this In-Yb11SSZ demonstrates a bending strength of 140 MPa, which is comparable to existing state-of-the-art electrolytes. Moreover, an electrolyte-supported cell (ESC) based on In-Yb11SSZ demonstrates a peak power density of 530 mW/cm² at 800 °C, with a degradation of 5.5 % in 150 h under harsh current conditions (460 mA/cm²). These results are ∼30–40 % higher than existing state-of-the-electrolyte-based ESCs, which shows the potential of this composition to be used as an electrolyte in ESCs for SOFCs.