ABSTRACT
Magnesium-based alloys have been extensively studied during last years, but the microcrystalline Mg2Ni alloy can reversibly absorb and desorb hydrogen only at high temperatures. It was found that the electrochemical activity of nanocrystalline hydrogen storage alloys can be improved in many ways, by alloying with other elements, by ball-milling the alloy powders with a small amount of nickel or graphite powders. For example, the surface modification of nanocrystalline hydrogen storage alloys with graphite by ball-milling leads to an improvement in both discharge capacity and charge-discharge cycle life. The concentration of hydrogen in produced nanocrystalline Mg2Ni alloys strongly decreases with increasing Mn contents. To avoid the surface oxidation, we have examined the effect of magnesium substitution by Al and Mn in Mg2Ni-type material. This alloying greatly improved the discharge capacities. Adding LaNi5, ZrV2 or TiFe in magnesium-based alloy improves the hydrogen storage performance at room temperatures.
