A fundamentally new magnesium-based hydrogen storage alloy material which makes it feasible and practical to use solid state storage and delivery of hydrogen to power internal combustion engine or fuel cell vehicles. These alloys have remarkable hydrogen storage capacity of well over 6 weight percent. The alloys also have extraordinary absorption kinetics such that the alloy absorbs 80 percent of its total capacity within five minutes. The alloys are in particle form where the particles have a size ranging from 30 to 70 microns. The alloys also have a dual phase structure (formed by cooling from the melt at a cooling rate of 103-104° C.). The dual phase structure is such that an intergranular region surrounds a major hydrogen storage phase thus providing the alloys with resistance to sintering during high temperature hydriding/dehydriding cycling thereof. As a result of the dual phase structure, the alloys have an extended cycle life.