Recent progress of high-performance interconnectors for SOFC: From materials, protective coatings, optimizing strategies, towards the real stack applications

As a crucial component in SOFC stacks, the interconnector electrically connects adjacent single cells while physically separating the fuel from the oxidant gas. Recent advances in intermediate-temperature SOFCs have enabled the use of more cost-effective metallic interconnectors. This review highlights recent progress and practical applications of high-performance SOFC interconnectors, outlining strategies to enhance device efficiency and long-term stability. It offers a comparative discussion on the barrier properties of protective coatings, including Mn-Co-based, Mn-Cu-based, and Fe-containing spinels, particularly when modified with doping strategies. Additionally, it summarizes fabrication technologies for effective protective coatings, such as screen printing with a two-step process, thermal spraying dispensing with post-treatment, magnetron sputtering, and electrophoretic deposition suitable for complex substrates. The oxidation behaviors of coated interconnectors under reducing and oxidizing atmospheres, as well as in real stack operating conditions, are thoroughly examined. Afterwards, comprehensive comparative analysis of the current market demands and economic feasibility was carried out for SOFC/SOEC applications. Finally, it discusses current challenges and future prospect, aiming to support the broader application and commercialization of SOFC stacks, particularly lightweight porous metal-supported SOFCs.