A critical factor for improving the long-term stability/reliability of solid oxide cell stacks is ensuring good adhesion between the stack components. Specifically, ensuring strong adherence between the oxygen electrode and the interconnect is challenging. This work compares the suitability of several materials as contact layers between a La0.6Sr0.4CoO3–δ-Ce0.8Gd0.2O2 composite oxygen electrode and Mn1.5Co1.5O4 or Co coated metallic interconnects. The contact materials were screened based on measurements of the interface fracture energy using four-point bending of sandwiched samples. The highest fracture energies were measured using a CuMn metallic, spinel forming foam as the contact layer. The fracture energy of the interface between a Mn1.5Co1.5O4 coated interconnect and the contact layer is ~8 times higher using the CuMn foam compared to using the conventional perovskite oxides (La0.8Sr0.2)0.98MnO3-δ, La0.6Sr0.4CoO3–δ, (La0.8Sr0.2)0.98MnO3-δ + La0.6Sr0.4CoO3–δ or LaNi0.6Fe0.4O3 as the contact material. The interface bonding and fracture mechanisms are discussed on the basis of scanning electron microscopy investigations.
- Solid oxide electrolysis cell
- Solid oxide fuel cell
- Contact layer
- Interface adhesion
- Fracture energy