Synthesis and Electrochemical Property of Lithium Storage Intermetallic Compounds

On the research for anode materials of rechargeable lithium battery, there have been interests in some kinds of intermetallic compounds. In the present study, some compounds such as Mg₂Ge and Mg₂Sn were synthesized by mechanical alloying (MA), and the structural analysis was carried out to Mg₂Ge by X-ray diffraction and neutron scattering to investigate the lithium insertion mechanism and the electrochemical properties were evaluated for Mg₂Sn having two types of crystal phases, cubic and orthorhombic. Furthermore, CeSn₃ was synthesized as a new anode material and the electrochemical properties were investigated.

As a result, it was found that, for Mg₂Ge, lithium atoms accommodate at the interstitial sites on lithiation without any degradation of the lattice and that, for Mg₂Sn, the orthorhombic phase with a loose lattice space has a larger charge-discharge capacity than the cubic one with a little tight lattice space. CeSn₃ was found to be an anode material with a high volumetric capacity and its cycling performance can be enhanced by initial mixing with lithium metal.