Dehydrogenation properties of doped LiAlH4 compacts for hydrogen generator applications

• Transition metal (TM) doped LiAlH4 can be compacted into stable compacts.
• At 80 °C, the H2 capacity of compacted LiAlH4 reaches up to 6.64 wt.% and 53.88 g l−1.
• Higher compaction pressure improves dehydrogenation kinetics of ZrCl4-doped LiAlH4.
• Storability of TM-doped LiAlH4 compacts is fairly good (<0.5 wt.%-H2 within 8 days).

Lithium aluminum hydride (LiAlH4) is an attractive hydrogen source for fuel cell systems due to its high hydrogen storage capacity and the moderate dehydrogenation conditions. In this contribution, TiCl3- and ZrCl4-doped LiAlH4 powders are prepared and pelletized under different compaction pressures in a uniaxial press. At constant 80 °C and a hydrogen partial pressure of 0.1 MPa, the maximal hydrogen release of suchlike LiAlH4 compacts amounts to 6.64 wt.%-H2 (gravimetric capacity) and 53.88 g-H2 l−1 (volumetric capacity). The hydrogen release properties of the doped LiAlH4 compacts are studied systematically under variation of the compaction pressure, temperature and hydrogen partial pressure. Furthermore, the volume change of doped LiAlH4 compacts during dehydrogenation as well as their short-term storability are investigated (shelf life).