A mini review on mathematical modeling of co-electrolysis at cell, stack and system levels

Co-electrolysis is a promising electrochemical process where simultaneous electrochemical reduction of steam and carbon dioxide take place to produce syngas. The co-electrolyzer based electrochemical fuel synthesis has gained considerable attention for converting renewable electricity into high value-added, easy storable and transportable fuels (e.g., methane, methanol, and ethanol) due to its environmental and thermodynamic benefits. Several experimental works have been carried out on the co-electrolyzer technology, especially on testing various cell component materials. In the last few decades, numerous mathematical modeling studies with various approaches have also been conducted to understand different phenomena (e.g., heat and mass transfer, fluid flow and electrochemical kinetics) in cell, stack, and system-level of co-electrolyzer. Existing review studies on the co-electrolyzers are limited and they lack comprehensive investigation of macro (component) and system scale modeling approaches, (rather mainly focus on the material development). Therefore, the main contribution of this paper is to present an extensive discussion and comparison of the studies that address cell, stack, and system scale mathematical modeling of co-electrolyzers. Moreover, remarkable conclusions drawn from these studies and suggestions for future directions are presented