New promising hydride based on the Cu-Li-Mg system

We investigated the ternary Cu-Li-Mg system, in particular the CuLi _xMg_2-x (x = 0.08) for hydrogen storage. Instead of crystallizing in an orthorhombic phase, as CuMg2, this phase presents a hexagonal structure very similar to that of NiMg₂ and NiMg ₂H_0.3. In this work we will discuss the structure of CuLi_xMg_2-x by the analysis of the neutron scattering data and first principles calculations. The first results for a hydride (deuteride) phase will also mentioned since preliminary studies at LANSCE showed that CuLi_xMg_2-x might absorb approximately 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 CuLi _xMg_2-x absorbs a considerable amount of hydrogen (close to DOE's expectations for hydrogen storage materials), but also will probably release it at a temperature in the range of 50 to 150 ^oC, where applications are easier to develop. Hence it should be possible to use this alloy with fuel cells or in batteries. Another important observation is that cycling has a strong effect on the structure of the hydride.