Water resistant hydrogen storage materials comprising encapsulated metal hydrides

Water resistance was imparted to ZrMn2, Mg-10%Ni and Ti-Zr-Fe-Mn alloys by encapsulating hydrided powders with ceramic overlayers derived from alcoxides. The treated powders readily absorbed hydrogen after immersed in water or showed essentially the same hydrogen capacity under a humidified hydrogen atmosphere (partial pressure of water: 0.6 kPa) as that under pure hydrogen. Loss of hydrogen capacity on the encapsulating treatment and/or poor kinetics of absorption and desorption due to coverage of surface are to be resolved prior to practical use of these composite materials.