Mg2Ge/Si Composite Electrodes Prepared by Gas-Deposition as Anodes for Lithium Rechargeable Battery

Mg2Ge/Si composite electrodes were prepared by a gas-deposition (GD) method and evaluated their electrochemical properties of anodes for Li rechargeable battery. The discharge capacity of the Mg2Ge/Si composite electrodes increased in comparison with that of Mg2Ge GD-film electrode. Among them, the Mg2Ge/Si composite electrode with 30 wt% Si content exhibited good cycle stability, which is 603 mAh g-1 after 200 cycles. At this composition of composite, each Si particle was surrounded with Mg2Ge layer, and the Mg2Ge layer appears to be easy to release the stress generated in the Si particle at Li insertion-extraction because Mg2Ge is more ductile than Si. Thus, we succeeded to develop the electrode which can take advantage of both high capacity of Si and good cyclability of Mg2Ge.