Multiphysics analysis and structural optimization of biomimetic flow fields in solid oxide electrolysis cells for CO₂/H₂O co-electrolysis

Abstract

Biomimetic flow field design serves as a promising approach to enhance mass transport and electrochemical performance for solid oxide electrolysis cell (SOEC). Nevertheless, its application in CO₂/H₂O co-electrolysis and the underlying transport–reaction coupling mechanisms remain insufficiently understood. In this study, three biomimetic flow fields, namely leaf-shaped, spiderweb-shaped, and fishbone-shaped configurations, are proposed for SOEC. A three-dimensional multiphysics model coupling fluid flow, mass transport, heat transfer, electrochemical reactions, and charge transport is developed to systematically evaluate gas distribution uniformity, pressure drop, temperature distribution, and electrochemical performance. The results demonstrate that biomimetic flow fields significantly improve reactant distribution uniformity compared with the conventional parallel flow field. Specifically, the spiderweb-shaped flow field presents the most uniform reactant supply, with the distribution uniformity of H₂O and CO improved by 23.5% and 22.1% relative to the parallel channel, thus effectively alleviating concentration polarization and achieving the best electrochemical performance. The leaf-shaped flow field exhibits the lowest pressure drop and most stable pressure distribution, showing distinct advantages in reducing pumping power consumption. Parametric studies reveal that the optimal rib width ratio is 3:1 for the spiderweb flow field and 2:2–2.5:1.5 for the fishbone flow field. The optimal channel width for both configurations is determined to be 2 mm, corresponding to 8 channels for the spiderweb design and 16 channels for the fishbone design. This work establishes quantitative correlations between flow field structure, transport characteristics, and electrochemical performance, providing reliable guidance for efficient SOEC design and optimization toward CO₂/H₂O co-electrolysis.