Thermo-Electro-Chemo-Mechanical Coupled Modeling of Solid Oxide Fuel Cell with LSCF-GDC Composite Cathode

Area of Science:

• Materials Science
• Chemical Engineering
• Electrochemistry

Background:

• Solid oxide fuel cell (SOFC) stack durability is influenced by complex interactions between transport phenomena, reaction kinetics, and mechanical stresses.
• Understanding these intricate relationships is crucial for optimizing SOFC performance and longevity.

Purpose of the Study:

• To develop and apply a comprehensive modeling framework integrating thermo-electro-chemo and contact thermo-mechanical aspects for SOFC analysis.
• To investigate the impact of different fuel species (hydrogen vs. methanol syngas) and flow arrangements (co-flow vs. counter-flow) on SOFC performance and mechanical integrity.

Main Methods:

• A combined modeling framework incorporating thermo-electro-chemo models for fuel conversion and electrochemical reactions.
• A contact thermo-mechanical model considering the effective mechanical properties of composite electrode materials.
• Parametric studies under typical operating conditions (0.7 V) focusing on temperature distribution, current density, and thermal stress.

Main Results:

• Hydrogen-fueled SOFCs exhibit higher peak temperatures (approx. 40 K) in specific central units compared to methanol syngas-fueled SOFCs.
• Charge transfer reactions are observed throughout the cathode layer in both fuel scenarios.
• Counter-flow arrangement enhances current density distribution for hydrogen-fueled SOFCs but has a minor effect on methanol syngas-fueled SOFCs.
• Methanol syngas feeding improves stress field inhomogeneity, and counter-flow reduces maximum tensile stress in the electrolyte by ~37.7% for methanol syngas-fueled SOFCs.

Conclusions:

• The developed modeling framework provides insights into SOFC performance and durability under various operating conditions.
• Methanol syngas as fuel and counter-flow arrangement show potential for mitigating thermal stress and improving mechanical stability in SOFCs.
• Optimizing fuel composition and flow configuration is key to enhancing the overall durability and efficiency of SOFC stacks.