A facile route to dually protected Ge@GeO2 composites as anode materials for lithium ion battery

A facile route has been adopted to yield amorphous carbon@graphene nanosheets@Ge@GeO2 (a-C@GNs@Ge@GeO2) composites, which were utilized as advanced anode materials for Li-ion battery. The rationally designed dual-protection for Ge@GeO2, i.e. encapsulation of amorphous carbon and cover of graphene nanosheets, has been successfully formed by magnesiothermic reduction and hydrothermal reaction followed by heat treatment. As a consequence, the designed composite electrode delivered a remarkable capacity of 729 mAh g−1 at a current density of 800 mA g−1 after 50 cycles at low temperature of 10 °C, with low capacity fading of 0.12% per cycle and excellent rate capability. Of special note is that high thermosensitivity of electrochemical performance of a-C@GNs@Ge@GeO2 has been observed. These advantages make a-C@GNs@Ge@GeO2 promising anode materials of advanced Li-ion battery for electric vehicle.