Microstructural and chemical design of materials for molten carbonate fuel cells: recent progress and challenges

Abstract

This work reviews recent progress in the microstructural and chemical design of materials for molten carbonate fuel cells (MCFCs), with emphasis on research conducted at the Faculty of Materials Science and Engineering, Warsaw University of Technology. The study demonstrates that the porous microstructure plays a decisive role in cell performance. Key parameters, including porosity, pore size distribution, tortuosity, constrictivity, and pore shape, strongly influence gas transport, electrolyte distribution, and electrochemical activity. The introduction of multimodal pore architectures and the use of both natural and synthetic porogens significantly enhanced power density by improving the electrolyte–gas interface and extending active reaction regions beyond the classical triple-phase boundary. Chemical modifications of cell components were found to improve durability and efficiency. Ceramic coatings, such as TiO2 and MgO, and composite TiO2/Ag layers reduced nickel dissolution rate from the cathode by up to 3 times while enhancing electrical performance. Furthermore, hybrid MCFC–SOFC systems incorporating oxygen-ion-conducting ceramics (SDC, YSZ) exhibited higher ionic conductivity. Computational modeling of porous microstructures, combined with experimental validation, provided insights into structure–property relationships and enabled the optimization of electrode design. Overall, the combined microstructural and chemical optimization offers an effective pathway to improve MCFC performance and durability.