High-pressure synthesis of lithium hydride

By compressing elemental lithium and hydrogen in a diamond anvil cell, we have synthesized lithium hydride (LiH) at pressures as low as 50 MPa at room temperature. Combined Raman spectroscopy and synchrotron x-ray diffraction measurements reveal that, once synthesized, LiH remains stable at 300 K up to 160 GPa in the presence of molecular hydrogen. The mixture of lithium hydride and molecular hydrogen and application of pressure alone cannot form a higher H-2 content hydride (LiHx, x > 1) as was suggested from the theoretical ab initio calculations and therefore, cannot be considered as a route to low-pressure hydrogen rich material metallization.