Three-dimensional ordered macroporous Cu/Fe3O4 composite as binder-free anode for lithium-ion batteries

A novel three-dimensional ordered macroporous (3DOM) Cu/Fe3O4 composite film was prepared by electrodepositing ferroferric oxide (Fe3O4) on the 3DOM Cu current collector. Characterizations via electron microscopies and X-ray diffractions confirmed that achieved 3DOM Cu/Fe3O4 composite inherited originally ordered porous structure, but has a layer of nanosized Fe3O4 on the surface of the 3DOM Cu framework. The obtained 3DOM Cu/Fe3O4 composite films were directly used as anodes of lithium ion batteries in the absence of conducting additives or binders. Results from electrochemical evaluations exhibited that the 3DOM Cu/Fe3O4 anode could deliver a stable capacity of 800 mAh g−1 up to 400 cycles, while fast capacity degradation with 200 mAh g−1 retained after 100 cycles was observed on Fe3O4 deposited on plane Cu substrate. The superior behavior of the 3DOM Cu/Fe3O4 composite anode is ascribed to its unique porous structure, which provides sufficient space for large volume change of Fe3O4 and greatly reduces the diffusion distance for Li-ion in the active material.