Reaction Mechanisms in the Li3AIH6/LiBH4 and AI/LiBH4 Systems for Reversible Hydrogen Storage. Part 1: H Capacity and Role of Al

摘要

Lithium-based complex hydrides, including lithium aluminum hydrides (LiAlH4, Li3AlH6) and lithium borohydride (LiBH4), are some of the most attractive materials for hydrogen storage due to their high hydrogen contents. In the present work, we investigated the hydrogen storage properties of combined systems of Li3AlH6/LiBH4 and Al/LiBH4, both of which exhibit favorable storage properties owing to the formation of AlB2 during dehydrogenation. TGA data showed that TiCl3-doped Li3AlH6/2LiBH4 and 0.5Al/LiBH4 release ～8.8 and ～8.4 wt 96 H2, respectively, with ～3.8 and ～5.8 wt % release after rehydro-genation of the dehydrogenation product. XRD results identified LiH and AlB2 phases in the dehydrogenated products, which suggests a mechanism by which Al contributes to the remarkable improvement of the reversible storage properties of LiBH4 in terms of temperature and pressure for H2 release and uptake,