Published March 21, 2018 | Version Final version
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Design of a Nanometric AlTi Additive for MgB2‑Based Reactive Hydride Composites with Superior Kinetic Properties

Authors/Creators

  • 1. Institute of Materials Research, Materials Technology, Helmholtz-Zentrum Geesthacht GmbH, Max-Planck-Strasse 1, D-21502 Geesthacht, Schleswig-Holstein, Germany
  • 2. Institute of Materials Research, Materials Technology, Helmholtz-Zentrum Geesthacht GmbH, Max-Planck-Strasse 1, D-21502 Geesthacht, Schleswig-Holstein, Germany and Department of Physicochemistry of Materials, Consejo Nacional de Investigaciones Científicasy Técnicas (CONICET), Centro Atómico Bariloche, Av. Bustillo km 9500 S.C. de Beriloche, Argentina
  • 3. Department of Metalphysics, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Centro Atómico Bariloche, Av. Bustillo km 9500, S.C. de Bariloche, Argentina
  • 4. Department of Chemistry and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
  • 5. Institute of Materials Research, Helmholtz-Zentrum Geesthacht, 21502 Geesthacht, Germany
  • 6. Pavia H2 Lab, C.S.G.I. & Department of Chemistry, Physical Chemistry Section, University of Pavia, 27100 Pavia, Italy
  • 7. Institute for Nanospectroscopy, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, Berlin 14109, Germany
  • 8. Department of Mechanical Engineering, Kyushu University, 744 Motooka Nishi-ku, Fukuoka 819-0395, Japan

Description

Solid-state hydride compounds are a promising option for efficient and safe hydrogen-storage systems. Lithiumreactive hydride composite system 2LiBH4 + MgH2/2LiH + MgB2(Li-RHC) has been widely investigated owing to its high theoretical hydrogen-storage capacity and low calculated reaction enthalpy(11.5 wt % H2 and 45.9 kJ/mol H2). In this paper, a thorough investigation into the effect of the formation of nano-TiAl alloys on the hydrogen-storage properties of Li-RHC is presented. The additive 3TiCl3·AlCl3 is used as the nanoparticle precursor. For the investigated temperatures and hydrogen pressures, the addition of ∼5 wt % 3TiCl3·AlCl3 leads to hydrogenation/dehydrogenation times of only 30 min and a reversible hydrogen-storage capacity of 9.5 wt %. The material containing 3TiCl3·AlCl3 possesses superior hydrogen-storage properties in terms of rates and a stable hydrogen capacity during several hydrogenation/dehydrogenation cycles. These enhancements are attributed to an in situ nanostructure and a hexagonal AlTi3 phase observed by high-resolution transmission electron microscopy. This phase acts in a 2-fold manner, first promoting the nucleation of MgB2 upon dehydrogenation and second suppressing the formation of Li2B12H12 upon hydrogenation/dehydrogenation cycling.

Notes

This research was supported by the European Marie Curie Actions under the ECOSTORE grant agreement number 607040 and by ANPCyT(Agencia Nacional de Promoción Cientifí ca y Tecnoloǵ ica)PICT 2015 1865. The authors gratefully acknowledge the support from The Danish National Research Foundation, Center for Materials Crystallography (DNRF93), The Innovation Fund Denmark (HyFill-Fast), and the Danish Research Council for Nature and Universe (Danscatt). The authors also thank CONICET (Consejo Nacional de Invetigaciones Cientifí cas y Teć nicas), ANPCy-T-(Agencia Nacional de Promoción Cientifica y Tecnologíica), CNEA (Comisión Nacional de Energía Atómica), HZBBESSY II Laboratory (Proposal ID: 20140433), and Dr. Anna- Lisa Chaudhary (Helmholtz-Zentrum Geesthacht).

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