Structural and Hydrogen Storage Properties of Y2Ni7 Deuterides Studied by Neutron Powder Diffraction

Véronique Charbonnier (1) , Junxian Zhang (1) , Judith Monnier (1) , Lionel Goubault (2) , Patrick Bernard (2) , Cesar Magén (3) , Virginie Serin (4) , Michel Latroche (1)

1 ICMPE - Institut de Chimie et des Matériaux Paris-Est
2 SAFT, Direction de la Recherche
3 University of Zaragoza - Universidad de Zaragoza [Zaragoza]
4 CEMES - Centre d'élaboration de matériaux et d'études structurales

The crystal structure and hydrogenation properties of Gd2Co7-type Y2Ni7 were investigated by X-ray diffraction (XRD), Sievert's method, and neutron powder diffraction. Unlike Nd2Ni7 and La2Ni7, Y2Ni7 exhibits three plateau pressures and forms three hydrides at room temperature. The maximum hydrogen capacity reaches 8.9 H/fu at 10 MPa at the first absorption cycle. The compound can be cycled by a solid-gas route, and structural properties are fully recovered after dehydrogenation. For the first time, the structural properties of rhombohedral A2B7Dx deuterides were studied. They were investigated by neutron powder diffraction at three different states of charge (x = 2.1, 4.1, and 8.8). Deuterium positions as well as variation of unit cell parameters are given and discussed in this paper. (Figure Presented).

Mots clés: Cobalt; Crystal structure; Deuterium compounds; Hydrogen storage; Neutron powder diffraction; Neutrons; Nickel; X ray diffraction; Absorption cycles; Hydrogen capacities; Hydrogen storage properties; Hydrogenation properties; Plateau pressures; Room temperature; States of charges; Unit cell parameters; Structural properties

Domaines: Physique [physics]

Véronique Charbonnier, Junxian Zhang, Judith Monnier, Lionel Goubault, Patrick Bernard, et al.. Structural and Hydrogen Storage Properties of Y2Ni7 Deuterides Studied by Neutron Powder Diffraction. Journal of Physical Chemistry C, 2015, 119 (22), pp.12218-12225. ⟨10.1021/acs.jpcc.5b03096⟩. ⟨hal-01760671⟩