Structural Analysis of LaNi_4.25Al_0.75 Hydride

The lanthanum (La)-nickel (Ni)-aluminum (Al) hydrides (LANA: LaNi_5−xAl_x, x < 1.0) have been extensively studied for their high volumetric storage capacity and improved durability to maintain a single-phase CaCu₅ structure through multiple absorption and desorption cycles. Pressure composition temperature (PCT) isotherms obtained for LANA have allowed for an understanding of the hydrogen sorption properties and the tunability of the PCT plateau region via doping. At the Savannah River Site, LaNi_4.25Al_0.75 (LANA0.75) has been utilized as a hydrogen storage material in the tritium facilities for decades. However, the structure characterization of the LANA0.75 hydride by X-ray diffraction has not yet been reported. This study examines LANA0.75 loaded to different hydrogen-to-metal atom ratios to elucidate both the position of hydrogen sites in the lattice and the structure of a fully hydrided β phase.