Effect of synthesis route on the hydrogen storage properties of 2MgH2–Fe compound doped with LiBH4

•Hydrogen storage properties of MgH2 and Fe doped with LiBH4 were investigated.•Hydrogenation reversibility was enhanced with the LiBH4.•Formation of MgH2 precludes the formation of Mg2FeH6.

The hydrogen storage properties of a 2:1 mol ratio of MgH2 and Fe with or without 10 wt.% of LiBH4 were investigated. Two doping methods were used: the first one consisted of two steps: first the 2MgH2 + Fe mixture was ball milled for 10 h and subsequently LiBH4 was added and milling resumed for 1 more hour. In the second method all materials were mixed and ball milled for 10 h. The first method produced materials with an hydrogen dehydrogenation capacity of 2.69 wt.% at 623 K and that could re-absorb 2.93 wt.% H2. The materials made by the second method presented a hydrogen dehydrogenation capacity of 2.98 wt.% at 623 K and re-absorbed 3.10 wt.% H2. For both methods, the rehydrided sample consisted only of MgH2. The reversibility of the reaction was enhanced with the LiBH4, but this additive, by acting as a catalyst for the formation of MgH2, precludes the formation of Mg2FeH6.