Neutron diffraction study on local structure of lithium storage intermetallic compound

The local structure of LixMg2Ge, which is a candidate for anode materials of lithium secondary batteries, was investigated using both X-ray diffraction (XRD) and neutron diffraction. It was found that the nearest interatomic distance of the Ge-Mg increases slightly in electrochemically lithiated Mg2Ge, (or LixMg2Ge), although any other large structural change was not obvious. The evidences suggest that lithium atoms (or ions) accommodate at interstitial sites of the Mg2Ge lattice to form a solid solution. From the Li-Ge correlation factors observed in the radial distribution functions, furthermore, lithium atoms in the lithiated Mg2Ge were supposed to occupy the sites equivalent to those of hydrogen atoms in Mg2NiH3.9 with an anti-fluorite structure.