Hydrogen storage properties of the (nLiAlH
4 + LiNH
2) hydride composite where
n = 1, 3, 11.5 and 30, synthesized by high energy ball milling have been investigated. The composite with the molar ratio
n = 1 releases large quantities of
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Hydrogen storage properties of the (nLiAlH
4 + LiNH
2) hydride composite where
n = 1, 3, 11.5 and 30, synthesized by high energy ball milling have been investigated. The composite with the molar ratio
n = 1 releases large quantities of H
2 (up to ~5 wt.%) during ball milling up to 100–150 min. The quantity of released H
2 rapidly decreases for the molar ratio
n = 3 and is not observed for
n = 11.5 and 30. The XRD studies indicate that the H
2 release is a result of a solid state decomposition of LiAlH
4 into (1/3)Li
3AlH
6 + (2/3)Al + H
2 and subsequently decomposition of (1/3)Li
3AlH
6 into LiH + (1/3)Al + 0.5H
2. Apparently, LiAlH
4 is profoundly destabilized during ball milling by the presence of a large quantity of LiNH
2 (37.7 wt.%) in the
n = 1 composite. The rate of dehydrogenation at 100–170 °C (at 1 bar H
2) is adversely affected by insufficient microstructural refinement, as observed for the
n = 1 composite, which was milled for only 2 min to avoid H
2 discharge during milling. XRD studies show that isothermal dehydrogenation of (nLiAlH
4 + LiNH
2) occurs by the same LiAlH
4 decomposition reactions as those found during ball milling. The ball milled
n = 1 composite stored under Ar at 80 °C slowly discharges large quantities of H
2 approaching 3.5 wt.% after 8 days of storage.
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