Mg
2Ge/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 Mg
2Ge/Si composite electrodes increased in comparison with that of Mg
2Ge GD-film electrode. Among them, the Mg
2Ge/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 Mg
2Ge layer, and the Mg
2Ge layer appears to be easy to release the stress generated in the Si particle at Li insertion-extraction because Mg
2Ge 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 Mg
2Ge.
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