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Ball milled (30 h) MgH 2 is impregnated on the pores/grooves of activated charcoal scaffold using a programmed heat treatment at 550 °C under 5 bar pure hydrogen ambient. The result obtained by this approach is better and more consistent than the materials prepared by metal infiltration at 650 °C or vacuum heated samples under 550 °C. The activation energy value (88 kJ/mol) obtained in the case of impregnated catalyst free material is far better than the activation energy value of the unconfined material (149 kJ/mol). The impregnated material can absorb hydrogen almost closer to its actual capacity at ∼1 bar under 170 °C. The low temperature desorption characteristics and ab/desorption behaviors are extensively analyzed and described. [ABSTRACT FROM AUTHOR]

In this work, the possibility of creating a polymer-based adaptive scaffold for improving the hydrogen storage properties of the system 2LiH+MgB2+7.5(3TiCl3·AlCl3) was studied. Because of its chemical stability toward the hydrogen storage material, poly(4-methyl-1-pentene) or in-short TPXTM was chosen as the candidate for the scaffolding structure. The composite system was obtained after ball milling of 2LiH+MgB2+7.5(3TiCl3·AlCl3) and a solution of TPXTM in cyclohexane. The investigations carried out over the span of ten hydrogenation/de-hydrogenation cycles indicate that the material containing TPXTM possesses a higher degree of hydrogen storage stability. [ABSTRACT FROM AUTHOR]

Abstract: Hydrogenation properties and mechanical stability of pellets made starting from compressed ball-milled MgH2 powders mixed with catalysts (Nb2O5 and graphite) and a binding agent (aluminium powder) have been investigated. Structural characterization with X-ray diffraction and gas–solid reaction kinetic and thermodynamic tests with a Sievert''s apparatus have been done on the samples up to 50 hydrogen absorption/desorption (a/d) cycles. The best cycling behaviour and mechanical strength stability have been observed for pellets of catalysed MgH2 powders added with 5 wt% aluminium annealed in vacuum at 450°C before starting the a/d cycles. This mechanical stability to cycles has been attributed to the formation of a solid solution of aluminium in magnesium. [Copyright &y& Elsevier]