MODIFIED MAGNESIUM BASED HYDROGEN STORAGE ALLOYS

摘要

A magnesium based hydrogen storage alloy powder which is useful as a hydrogen supply material for powering internal combustion engine or fuel cell vehicles. The alloy contains greater than about 85 atomic percent magnesium, about 2-8 atomic percent nickel, about 0.5-5 atomic percent aluminum and about 2-7 atomic percent rare earth metals or mixtures of rare earth metals. The rare earth elements may be Misch metal and may predominantly contain Ce and/or La. The alloy may also contain about 0.5-5 atomic percent silicon. The alloys can be modified to store more than 4 wt.%, preferably more than 4.5 wt.%, most preferably more than 5 wt.% hydrogen, with a reduced hydride bond strength (i.e. about 64 kJ/mole) which allows for economic recovery of the stored hydrogen. Also, they have a plateau pressure about two times greater than pure Mg and comparable bond energies and plateau pressures to Mg2Ni alloys, while reducing the amount of incorporated nickel by 25-30 atomic %. This reduced nickel content greatly reduces cost of the alloy. Also, while the kinetics of the alloy are improved over pure Mg, the storage capacity of the alloy is significantly greater than the 3.6 wt.% of Mg2Ni material.