Advancing the multiscale understanding on solid oxide electrolysis cells via modelling approaches: a review

Solid oxide electrolysis cell (SOEC) is a clean and highly efficient technology that converts electrical energy into chemical energy, which is regarded as a promising approach to enable hydrogen production, carbon dioxide utilization and nitrogen reduction, and more. One of the main challenges faced by SOEC is performance descending. Numerical modelling is expected to provide insights on performance evolution and material degradation. Different assumptions and methodologies are applied to model the physicochemical processes in a length scale from molecule scale to system scale. It is rational and can be brought great convenience into modelling to make assumptions and simplifications when focusing on a single length scale, however, valuable details can be missing. Multiscale modelling is expected to maintain more information and generate a systematic understanding of the working mechanism of SOEC. In this paper, the modelling methods at various scale levels are summarized. Then, the recent advances in numerical studying on SOEC are reviewed with a focus on multiscale modelling works bridging two or more contiguous length scales. The challenges and future research directions are proposed to promote the multiscale modelling.