Porous iron oxide coating on β″-alumina ceramics for Na-based batteries

Porous iron oxide films with controlled pore structure to modify the surface of β″-alumina ceramic electrolyte were synthesized through a low-cost wet chemistry method. The pore diameter of the iron oxide coatings can be tuned mainly by the amount of pore-forming agent polyethylene glycol. The iron oxide coatings were demonstrated to improve the wettability of the β″-alumina ceramics by molten sodium. Furthermore, Na/β″-alumina/Na cells were used to investigate the interfacial properties between sodium and the β″-alumina electrolytes. The results obtained at 350 °C revealed that the coating effectively alleviated the Na/β″-alumina interfacial polarization.