Facile synthesis of germanium-reduced graphene oxide composite as anode for high performance lithium-ion batteries

Germanium is a promising anode material for lithium ion batteries (LIBs) due to its high specific capacity, but it still suffers from poor cyclability. A simple method was developed to synthesize Ge-reduced graphene oxide nanocomposites using organic germanium as a precursor. The nanocomposites exhibit improved electrochemical performance with a reversible specific capacity of 814 mA h g(-1) after 50 cycles at a current density of 0.1 A g(-1). When cycled at a high current density of 2 A g (1), they still deliver a reversible specific capacity of 690 mA h g(-1) after 150 cycles. The improved electrochemical performance is attributed to the unique nanostructure (0D electro-active particles in 2D mixed conducting matrix), which conferred a variety of advantages: high flexibility of the graphene sheets for accommodating the volume change, good electrochemical coupling and short transport length for ions and electrons, enabling lowcontact resistances.