| Abstract Scope |
Fast oxygen-ion conductors are essential for emerging energy technologies, including solid oxide fuel cells, electrolysis, oxygen separation, and sensors. Bismuth oxide is the holy grail for oxygen-ion transport, with its high-temperature δ-phase exhibiting exceptional conductivity beyond state-of-the-art electrolytes. The δ phase can be stabilized by doping, yet the stabilized phases exhibit severe conductivity decay at lower temperatures. Here, we employ first-principles calculations to elucidate fundamental degradation mechanisms: structural instability, reduction, oxygen-sublattice ordering, and decayed ionic mobility. Guided by these insights, we conduct a high-throughput computational screening spanning the elemental doping space and derive compositional design principles for Bi2O3-based high-performance conductors. We further develop an autonomous experimental platform integrating robotic synthesis, high-throughput characterization, and electrochemical testing to optimize composition chemistry guided by these principles. This integrated approach enables the discovery of doped Bi2O3-based oxygen-ion conductors with record-high oxygen conductivity and provides a scalable pathway toward accelerated development of next-generation energy materials. |