Preparation and Hydrogen Storage Properties of La<sub>0.4</sub>Y<sub>0.6</sub>Ni<sub>4</sub> Superlattice Alloy with Single AB<sub>4</sub>-type Structure

In the context of low-pressure solid-state hydrogen storage applications, research has been conducted to address the issue of structural degradation during the hydrogen absorption and desorption cycles of AB₄-type La-Y-Ni-based superlattice alloys. The La_0.4Y_0.6Ni₄ superlattice alloy with single AB₄-type structure is obtained by arc melting and quenching at 1170 ℃. The alloy has a rhombohedral 3R-La₅MgNi₂₄-type superlattice structure composed of [(La_0.42Y_0.58)Ni₅] and [(La_0.36Y_0.64)₂Ni₄] subunits with a ratio of 4 ∶ 1. At a temperature of 0 ℃, the La_0.4Y_0.6Ni₄ single-phase alloy exhibits a maximum hydrogen absorption capacity of 1.54wt%. Hydrogen-induced amorphization of the [(La_0.36Y_0.64)₂Ni₄ ] sub-unit leads to a reversible hydrogen desorption capacity of 0.95wt%. The relatively high hydrogen desorption plateau pressure (0.45 MPa) confers significant potential for application in low-pressure solid-state hydrogen storage.