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. - Highlights: • Three-dimensional ordered macroporous (3DOM) Cu/Fe₃O₄ binder-free anode was prepared. • A layer of nanosized Fe₃O₄ grew on the surface of 3DOM Cu framework. • 3DOM Cu/Fe3O4 anode delivered capacity of 800 mAh/g up to 400 cycles. • 3DOM structure accommodated volume change and reduced Li⁺ diffusion path.