Hydrogen storage materials protected by a polymer shell

A simple approach for the protection of hydrogen storage materials is based on interfacial polymer precipitation induced by solvent evaporation. Sodium borohydride is successfully protected with a polystyrene shell by co-precipitation. This shell provides a hydrophobic barrier for water diffusion into the container interior. Simultaneous nucleation of sodium borohydride inside the droplets of the disperse phase and formation of a surrounding polystyrene shell during gradual solvent evaporation led to the development of structures consisting of a sodium borohydride core and a polymer shell. Confocal fluorescence microscopy, scanning electron microscopy and transmission electron microscopy reveal the crystalline interior and polymer shell of the fabricated microcontainers. FTIR spectroscopy proves the presence of a sodium borohydride core and a polystyrene shell. The stability of sodium borohydride microcontainers is increased as compared to the unprotected material by 2.5 times during storage at 100% humidity.