Thermo-mechanical analysis of 3D manufactured electrodes for solid oxide fuel cells

Additive manufacturing has widened the scope for designing more performing microstructures for solid oxide fuel cells (SOFCs). Structural modifications, such as the insertion of ceramic pillars within the electrode, facilitate ion transport and boost the electrochemical performance. However, questions still remain on the related mechanical requirements during operation. This study presents a comprehensive thermal-electrochemical-mechanical model targeted to assess the stress distribution in 3D manufactured electrodes. Simulations show that a dense pillar increases the stress distribution by ca. 10 % compared to a flat electrode benchmark. The stress is generated by the material thermal contraction and intensifies at the pillar-electrolyte junction while external loads have negligible effects. An analysis on manufacturing inaccuracies indicates that sharp edges, surface roughness and tilted pillars intensify the stress; nonetheless, the corresponding stress increase is narrow, suggesting that manufacturing inaccuracies can be easily tolerated. The model points towards robust design criteria for 3D manufactured electrodes.