Green synthesis of GeO2/graphene composites as anode material for lithium-ion batteries with high capacity

A facile green solution route using only GeO2 powder, graphene oxide and purified water has been developed to prepare a GeO2/graphene composite, in which the GeO2 particles are wrapped in graphene nanosheets. When utilized as an anode material for lithium-ion batteries (LIBs), the composite electrode exhibits a high initial reversible charge capacity of 1637 mA h g(-1), while bare GeO2 particles only show a capacity of 150 mA h g(-1). The high capacity of the GeO2/graphene composites was ascribed to the reversible utilization of Li2O, which was confirmed by X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV) techniques. It is noteworthy that the solvent, reagents, as well as instruments we used in the preparation process of the composites are innocuous and inexpensive. Thus, the GeO2/graphene composite electrode can be used as a promising high capacity anodic material for LIBs.