Reversible hydrogen storage in LiBH4/Ca(AlH4)2 systems

• Published in: International journal of hydrogen energy Vol. 38; no. 8; pp. 3291 - 3296
• Main Authors: Liu, D.M., Gao, C., Qian, Z.X., Si, T.Z., Zhang, Q.A.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 19.03.2013; Elsevier
• Subjects: Alternative fuels. Production and utilization; Applied sciences; Calcium alanate; Chemistry; Energy; Exact sciences and technology; Fuels; Hydrogen; Hydrogen storage materials; Hydrogen storage properties; Inorganic chemistry and origins of life; Lithium borohydride; Miscellaneous; Preparations and properties; Reactive hydride system; Hydrogen storage materials; Lithium borohydride; Reactive hydride system; Hydrogen storage properties; Calcium alanate; Hydrogen storage; Hydrogen; Hydrides; Lithium Tetrahydroborates; X ray diffraction; Calcium Tetrahydroaluminates; Reactive system; Dehydrogenation; Reversibility
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2013.01.033

To improve the hydrogen storage property of LiBH4, the LiBH4/Ca(AlH4)2 reactive systems with various ratios were constructed, and their de-/hydrogenation properties as well as the reaction mechanisms were investigated experimentally. It was found that the sample with the LiBH4 to Ca(AlH4)2 molar ratio of 6:1 exhibits the best comprehensive hydrogen storage properties, desorbing hydrogen completely (8.2 wt.%) within 35 min at 450 °C and reversibly absorbing 4.5 wt.% of hydrogen at 450 °C under a hydrogen pressure as low as 4.0 MPa. During the first dehydrogenation process of the LiBH4/Ca(AlH4)2 systems, the CaH2 and Al particles were in situ precipitated via the self-decomposition of Ca(AlH4)2, and then reacted with LiBH4 to form CaB6, AlB2 and LiH. Whereafter, the sample can cycle between LiBH4 + Ca(BH4)2 + Al in the hydrogenated state and CaB6 + AlB2 + LiH in the dehydrogenated state. ► The hydrogen storage property of LiBH4 can be improved by combining with Ca(AlH4)2. ► The LiBH4/Ca(AlH4)2 (6:1) system exhibits the best comprehensive property. ► 4.5 wt.% of hydrogen can be reabsorbed at 450 °C under 4.0 MPa hydrogen pressure. ► LiBH4 and Ca(BH4)2 can be formed upon hydrogenation.