Design guidelines for the manufacturing of the electrode-electrolyte interface of solid oxide fuel cells

• Published in: Journal of power sources Vol. 437; p. 226888
• Main Authors: Chueh, Chih-Che, Bertei, Antonio, Nicolella, Cristiano
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.10.2019
• Subjects: Additive manufacturing; Electrode design; Optimization; Solid oxide fuel cells; Solid oxide fuel cells; Additive manufacturing; Electrode design; Optimization
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2019.226888

The advent of 3D printing has ushered in the scope for designing microstructures for solid oxide fuel cells (SOFCs) with enhanced power density and lifetime. Additive manufacturing can introduce structural modifications such as dense electrolyte pillars embedded within the porous electrode domain to facilitate ion transport. This study presents comprehensive guidelines to the design of electrolyte pillars to minimize the polarization resistance and increase the electrode robustness by means of a numerical model comprising electrochemical phenomena and structural mechanics. Numerical results show that the introduction of rectangular and trapezoidal pillars can reduce electrode polarization provided that an electrode thickness larger than the active thickness is used. Lateral fins or any protrusions sticking out the pillar hinder gas transport and should be avoided. Mechanical stress, up to twice the external compressive load, accumulates at the pillar/electrolyte junction, indicating that sharp corners must be smoothed during pillar manufacturing. Additional considerations regarding the fabrication accuracy and minimum resolution are addressed too. Although a simple and general recipe for the optimal electrode fabrication is not possible, the rationale behind the strategies for the best pillar design are presented and critically discussed. [Display omitted] •Modelling guidelines for insertion of pillars in porous SOFC electrodes.•Rectangular and trapezoidal YSZ pillars can reduce the polarization resistance.•Pillar height must be smaller than electrode thickness while fins should be avoided.•Trapezoidal pillars require stricter manufacturing precision than rectangular ones.•Mechanical stress intensifies at pillar/electrolyte junction: avoid sharp edges.