Internal steam generation via mixed ion-conducting fuel cell for methane reforming at 600ºC

Fuel cells provide efficient and eco-friendly alternatives to traditional combustion-based power generation. Among various types, protonic ceramic fuel cell (PCFC) has emerged as promising candidates due to their ability to operate at lower temperature and feasibility for methane usage. Although solid oxide fuel cell (SOFC) naturally generates steam at the anode during operation, PCFC necessitates the installation of an external steam generator to for mitigating carbon coke formation and incomplete conversion. This study introduces a novel mixed ion-conducting fuel cell (MIFC) design for internal steam generating in the anode side of PCFC. The MIFC was fabricated with BaZr _0.1 Ce _0.7 Y _0.1 Yb _0.1 O _3-δ (BZCYYb) as a proton conductor and Sm _0.2 Ce _0.8 O _2-δ (SDC) as an oxide ion conductor via dip-coating leveraging the shrinkage difference and coating slurry viscosities. The layered structure of the MIFC significantly improved maximum power densities of 0.40 W cm ^-2 for hydrogen and 0.20 W cm ^-2 for methane at 600 ^o C. The layered MIFC also achieved highly table performance at long-term methane reforming at 0.1 A cm ^-2 for 50 hours. Internal steam generation from the layered structure contributed to higher power densities and mitigated coke formation. The results highlight its potential for applications using hydrocarbon fuels.