Complex hydrides for hydrogen storage

There has been significant effort made toward the utilization of alantes, amides and borohydrides as onboard hydrogen carriers. Alanates are attractive because sodium and lithium is commercially available while another, magnesium, can be readily prepared with sodium alanate and magnesium hydride via a metathesis reaction. However, only sodium alanate can be directly charged under hydrogen pressure and is the only member of the alanates class plausible for practical hydrogen storage for vehicular applications. Another is amide, which have traditionally been used as reagents in synthetic organic chemistry. There are various amides, including Mg(NH2)2 and a better solid-gas reaction of MgH2 with ammonia for the preparation of the single phases Mg(NH2)2 and MgNH.97,98. Their hydrogen storage properties are also good, with a 25% reduction of the hydrogen storage capacity. Ammonia formation accounts for about 7% of the capacity loss. Another is through borohydrides by the reaction of ethyl lithium with diborane. They are typically prepared by chemical methods like by the reaciton of the metal hydride with diborane in a solvent.