Component-level modeling of solid oxide water electrolysis cell for clean hydrogen production

In this study, a combined thermal and electrochemical approach of solid oxide water electrolysis cells (SOECs) is developed to investigate hydrogen production under high temperatures. The mathematical model assesses the high-temperature electrochemical process utilizing water steam to produce hydrogen and oxygen gases. The model incorporates reversible voltage dependency linked to the operating temperature and gas partial pressure. It also integrates Fick's and Ohm's laws to account for the species and charge transport phenomena. Ohmic, activation, and concentration overpotentials are included as the main irreversibility sources during SOEC operation. This research contributes to the advancement of green hydrogen production technologies. The model was successfully validated against two sets of experimental data. Various correlations for the electrolyte ionic conductivity are compared and discussed. It is shown that the ohmic polarization is a main contributor to the performance loss for one SOEC in validation. Furthermore, it was found that the operation can utilize external heat for hydrogen production under a current of less than similar to 0.2 A/cm2 for the considered SOEC configuration. The demonstrated capability of utilizing external heat for hydrogen production at low current densities enhances the feasibility of integrating SOEC technology with diverse energy sources. In addition, the thermal interfacial resistance between the flow plate and electrode is included in our thermal model, showing an important impact on SOEC thermal management by using literature's experimental data for the resistance. This analysis reflects the importance of efficient thermal management in SOEC systems. The modeling tool has broad applications and can be instrumental in optimizing SOEC and its component design, materials, and its integration with renewable energy and other heat sources like nuclear energy and industry waste heat for clean hydrogen production.