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

Abstract

We investigated the ternary Cu-Li-Mg system, in particular the CuLi xMg2-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 2H0.3. In this work we will discuss the structure of CuLixMg2-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 CuLixMg2-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 xMg2-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. © 2010 IOP Publishing Ltd.