Facile synthesis of Ge@C core-shell nanocomposites for high-performance lithium storage in lithium-ion batteries.

Herein, we report a facile and "green" synthetic route for the preparation of Ge@C core-shell nanocomposites by using a low-cost Ge precursor. Field-emission scanning electron microscopy and transmission electron microscopy analyses confirmed the core-shell nanoarchitecture of the Ge@C nanocomposites, with particle sizes ranging from 60 to 100 nm. Individual Ge nanocrystals were coated by a continuous carbon layer, which had an average thickness of 2 nm. When applied as an anode materials for lithium-ion batteries, the Ge@C nanocomposites exhibited a high initial discharge capacity of 1670 mAh g(-1) and superior rate capability. In particular, Ge@C nanocomposite electrodes maintained a reversible capacity of 734 mAh g(-1) after repeated cycling at a current density of 800 mA g(-1) over 100 cycles.