Dehydrogenation properties of the LiNH2BH3/MgH2 and LiNH2BH3/LiBH4 bi-component hydride systems for hydrogen storage applications

Lithium amidoborane (LiAB) is known as an efficient hydrogen storage material. The dehydrogenation reaction of LiAB was studied employing temperature-programmed desorption methods at varying temperature and H2 pressure. As the dehydrogenation products are in amorphous form, the XRD technique is not useful for their identification. The two-step decomposition temperatures (74 and 118 °C) were found to hardly change in the 1–80 bar pressure range. This is related either to kinetic effects or to thermal dependence of the reaction enthalpy. Further, the possible joint decomposition of LiNH2BH3 with LiBH4 or MgH2 was investigated. Indeed LiBH4 proved to destabilize LiAB, producing a 10 °C decrease of the first-step decomposition temperature, whereas no significant effect was observed by the addition of MgH2. The 5LiNH2BH3 + LiBH4 assemblage shows improved hydrogen storage properties with respect to pure lithium amidoborane.