LiBH4 is a promising material to store hydrogen because of its interesting characteristics. It has high hydrogen gravimetric capacity (18.4 wt%) which is far above of the target established by the International Energy Agency (5.0 wt% of hydrogen) and low weight [1–3]. However, the main constraint of LiBH4 is its high thermodynamic stability (ΔHLiBH4= 74 kJ.mol−1 H2) wich consequently results in an elevated dehydrogenation temperature (Tdesorption= 370 ºC at 1 bar) and harsh hydrogenation

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... ons (600 ºC and 155 bar of hydrogen) [4]. Thus, the physicochemistry of LiBH4 precludes its practical application, for example as a medium to store hydrogen for vehicular purposes. One of the applied concepts to reduce the stability of LiBH4 is the combination with other compunds such as binary hydrides as for example MgH2. This approach leads to the reduction of the enthalpy of the overall reaction (2LiBH4 + MgH2 ↔ MgB2 + 2LiH + 4 H2, ΔH = 40.5 kJ.mol-1 H2) and reversible decomposition of the borohydride via boride compounds formation [5, 6]. Nonetheless, the reacction between LiBH4 and MgH2 may have kinetic restrictions that do not permit to operate at temperatures below 400 ºC as predicted by thermodynamic reaction (T(1 bar) = 225ºC). In order to improve the operative conditions at wich the 2LiBH4 + MgH2 reactive hydride composite uptake/release hydrogen, we add Fe and F3Fe as catalyist. We assess the microestructural and thermal properties before and after hydrogen cycling and the rate of absorption/desorption of hydrogen as well as the hydrogen cycling of 2LiBH4 + MgH2 doped with Fe and F3Fe. Experimental results show that the kinetics of 2LiBH4 + MgH2 is improved by the catalyst addition, reaching reversible capacities of abo [...]