First-Principles Computational Design and Discovery of Solid-Oxide Proton Conductors

Solid-oxide proton-conducting materials are key components for hydrogen-based energy devices, including solid-oxide fuel cells, electrolyzers, hydrogen separation membranes, and novel electronic computing devices. The further development of these devices requires proton-conducting materials with high proton conductivity and good stability with hydrogen and water under the device-operating environment. In this study, we perform a systematic first-principles computational study on a wide range of ternary oxide materials to identify new proton conductor materials and to understand the role of both cations and compositions on material stability and proton conductivity. By analyzing the computational results of over 5000 oxide materials, we reveal how the cation species and mole fraction affect water stability and hydrogen insertion capability. By studying proton diffusion in many different materials, our analyses show that oxide materials with connected BO6 octahedra are optimal for fast proton diffusion. Following the understanding, a high-throughput computation identifies a dozen oxide materials with good water stability, good proton incorporation capability, and fast proton diffusion. This study provides fundamental understanding and design principles to develop oxide materials with fast proton diffusion and good stability.