Investigation on Crystal Structure and Thermodynamic Properties of La0.6Nd0.4Ni4.8Mn0.2Cux (x=0∼0.4) Hydrogen Storage Alloys

The influences of Cu content on the crystal structure, thermodynamic properties and hydrogen storage performance of La0.6Nd0.4Ni4.8Mn0.2Cux (x=0, 0.1, 0.2, 0.3, 0.4) alloys were investigated and the relationships among the lattice parameter, plateau pressure and Gibbs free energy were analyzed. It was found that with the increase of the Cu content, the lattice parameter a shrunk and c expanded while the cell volume increased when x <= 0.2 and then decreased when x >= 0.3. The plateau pressure linearly decreased with the increase of a. The Seitz radius decreased with the increase of the Cu content and showed a clear linear relationship with Delta S-d/Delta H-d and an obvious hyperbolic relationship with Delta S-a/Delta H-a.