New Promising Hydride Based on the Cu-Li-Mg System

Abstract

We investigated the ternary Cu-Li-Mg system, in particular the CuLixMg2-x (x =0.08) for hydrogen storage. Instead of crystallizing in an orthorhombic phase, as CuMg2, thisphase presents a hexagonal structure very similar to that of NiMg2 and NiMg2H0.3. In this workwe will discuss the structure of CuLixMg2-x by the analysis of the neutron scattering data andfirst principles calculations. The first results for a hydride (deuteride) phase will alsomentioned since preliminary studies at LANSCE showed that CuLixMg2-x might absorbapproximately 5.3 to 6 wt% of H at an equilibrium pressure of approximately 27 bar at 200 oC.If these results are confirmed in future work, this will mean that, not only CuLixMg2-x absorbs aconsiderable amount of hydrogen (close to DOEs expectations for hydrogen storagematerials), but also will probably release it at a temperature in the range of 50 to 150 oC, whereapplications are easier to develop. Hence it should be possible to use this alloy with fuel cellsor in batteries. Another important observation is that cycling has a strong effect on the structureof the hydride.