Chen Demin

Hydrogen Storage Properties of La1-xYxNi5-yAly Alloys

Abstract The feasibilities of La 1- x Y x Ni 5-y Al y alloys ( x =0.6, 0.7; y =0.1, 0.2) applied in metal hydride high-pressure compressor were investigated systematically in terms of the crystal structure, hydrogen absorption/desorption properties and pulverization resistance. XRD analyses show that all the investigated alloys present CaCu 5 type hexagonal structure and the unit cell volume decreases with the increase of Y, but increases with the increase of Al content. The pressure-composition isotherms and absorption kinetics were measured at 20, 30 and 40 °C by the volumetric method. Hydrogen absorption/desorption measurement reveals that Y and Al could effectively increase and decrease the equilibrium hydrogen pressure, respectively. They are ideal elements to adjust the equilibrium hydrogen pressure of LaNi 5 -based alloys without other remarkable negative influences. We think that the alloys could be matched as ‘alloy pairs’ and applied in a double-stage metal hydride compressor; the compressor could boost the feed hydrogen gas at room temperature from 2 MPa to 35∼40 MPa at 135∼155 °C.