Facile synthesis of three-dimensional Cu/Fe3O4 nanowires as binder-free anode for lithium-ion batteries

A three-dimensional (3D) Cu/Fe3O4 anode material was synthesized successfully via a simple and flexible route. Cu nanowires grew on Cu sheet directly by oxidation and reduction as 3D current collector, Fe3O4 nanosheets were coated on the collector surface by electrodeposition to form 3D Cu/Fe3O4 nanocomposite. The characterization results showed that oxidation time affects the morphology of Cu nanowires greatly, the collector has optimum 3D nanostructure at 200 s oxidation with high performance. The 3D Cu/Fe3O4 anode possessed high cycling capability, the capacity reached 700 mAh/g after 300 cycles at 0.5 A/g. And it exhibited high rate performance, the capacity reached 482 mAh/g at 2 A/g and it recovered to 853.5 mAh/g at 0.2 A/g after 100 cycles of different rate tests. The high performance is ascribed to the unique 3D nanostructure of current collector, which provides sufficient space for large volume change and stress release, and reduces the distance for transporting lithium ions and electrons.