Reversible hydrogen storage in the lithium borohydride—calcium hydride coupled system

We report large reversible hydrogen storage in a new coupled system, LiBH4/CaH2, via the reaction 6LiBH4 + CaH2 ↔ 6LiH + CaB6 + 10H2 having a theoretical hydrogen capacity of 11.7 wt% and an estimated reaction enthalpy of ΔH = 59 kJ/mol H2. Samples that include 0.25 mol (18.2 wt%) TiCl3 reproducibly store 9.1 wt% hydrogen, corresponding to 95% of the available hydrogen. H2 is the only evolved gas detected by mass spectrometry. X-ray diffraction confirms that the sample cycles between LiBH4 and CaH2 in the hydrogenated state and LiH and CaB6 in the dehydrogenated state.