Low-cost shape-control synthesis of porous carbon film on β″-alumina ceramics for Na-based battery application

► Fabricating uniform porous carbon films with tunable structural parameters on the surface of β″-alumina ceramics. ► Effective connection between carbohydrate and PMMA through hydrogen bonds. ► Largely improving the wettability of the β″-alumina surface by molten sodium. ► Alleviating the polarization problem of the sodium/β″-alumina interface in Na-based batteries by the porous coating.