Structural, thermodynamic and electrochemical properties of over-stoichiometric La_1-y(Ni_1-zSn_z) _5+2y hydride forming compounds

The structural properties of four tin substituted La_1-y(Ni _1-zSn_z)_5+2y compounds have been investigated by X-ray powder diffraction (XRD) and microprobe analysis as a function of both tin amount (z) and over-stoichiometry (y). Their thermodynamic behaviour toward hydrogen gas absorption/desorption has been measured up to 1MPa. Their electrochemical capacities and cycle lives have been determined. From these analyses, the different behaviour observed for these materials have been correlated to their structural and thermodynamic properties.