Study On The Hydrogen Storage Characteristics And Electrochemical Performances Of La-Mg Based Hydrogen Storage Compounds

AB₃-type La-Mg-based hydrogen storage alloys are promising candidates for reversible hydrogen storage because of their high discharge capacities, easy activation and good hydrogen pressure. In this paper, a set of La-Mg-Ni-Co-Al alloys are prepared in high frequency induction furnace under Ar atmosphere. The influences of replacing element in La-Mg based hydrogen storage alloys on the electrochemical properties and the hydrogen storage properties have been studied.1. La_0.7Mg_0.3Ni_2.75-xAl_xCo_0.75 (x=0.0-0.4) hydrogen storage alloys were prepared and the effects of partial substitution Al for Ni on the structure, electrochemical properties of the alloys were investigated systematically. In the alloys, Mg₂Ni phase appears in all alloys and La(Ni, Co, Al)₅ phase with the hexagonal CaCu₅-type structure replaces La(Ni, Co)₅ phase with Al substituting for Ni. The plateau pressure declines gradually and the hysteresis between the hydrogen absorption and desorption decreases with the amount of substitution Al for Ni increasing. The substitution Al for Ni can improve thermal stability for La_0.7Mg_0.3Ni_2.75-xAl_xCo_0.75 (x=0.0-0.4) alloy hydrides, slow...