A magnetite nanocrystal/graphene composite as high performance anode for lithium-ion batteries

Highlights: ► Single step solvothermal route to Fe3O4/graphene nanocomposites. ► Nanocomposites can act as anode materials in lithium-ion batteries. ► Electrochemical performances are affected by graphene contents. Optimized graphene additive ratio leads to excellent cycling stability and total capacity. - Abstract: A facile single step solvothermal route has been developed to prepare a composite of Fe3O4 nanoparticles and graphene nanosheets. The synthetic protocol takes advantage of the ethylene glycol assisted partial reduction of Fe3+ species to form Fe3O4, the reduction of graphene oxide into graphene, and the preferential attachment of fine Fe3O4 nanoparticles onto graphene sheets in one step. No additional reductive agent or calcination step is needed, which favors an effective, operationally simple and low-cost preparation process. The cycling properties of Fe3O4/graphene nanocomposite have been evaluated by galvanostatic charge–discharge measurements. The effect of graphene additive ratios on electrochemical performance has been investigated. The results show that the nanocomposite with a moderate graphene content of 18.5 wt% integrates high reversible capacity and good cyclic stability, delivering a capacity of 750 mAh/g after 40 cycles at 50 mA/g.