Enhanced ion transport and performance in electrolyte-supported single cells using infiltrated composite electrolyte with oxygen-conducting matrix

Molten carbonate fuel cells (MCFCs) represent a type of high-temperature fuel cell technology that employs a molten carbonate salt mixture as an electrolyte. This electrolyte is housed within a porous ceramic matrix made of beta-alumina, which is chemically inert. However, the use of Lithium aluminate (LiAlO₂) as a component in the ceramic matrix presents a challenge due to its poor ionic conductivity, which is measured at the level 10⁻⁶ S/cm at 650^oC. To improve the ionic conduction characteristics of solid electrolytes, a composite electrolyte can be employed, which involves a mixed conduction mechanism with various ion conducting ions. This approach commonly utilizes a ceria-based material as the matrix, with the incorporation of carbonates through infiltration. The ionic conductivity of a composite electrolyte consisting of 51 % SDC and 49 % carbonate, achieved through infiltration, is measured at 0.49 S/cm at a temperature of 700 °C. This conductivity value surpasses that of the current leading LiAlO₂-carbonate electrolyte, which stands at 0.35 S/cm at the same temperature.