Electrochemical deposition of Fe₃O₄ nanoparticles and flower-like hierarchical porous nanoflakes on 3D Cu-cone arrays for rechargeable lithium battery anodes

A novel 3D nanostructured Fe₃O₄/Cu-cone arrays (Cu-CAs) anode is prepared by template-free chemical deposition of Cu-CAs on a flat Cu current collector followed by galvanostatic electrodeposition of polycrystalline Fe₃O₄ nanoparticles (NPs) and Fe₃O₄ nanoflakes (NFs) from electrolyte containing 0.1 M tri-ethanol-amine (TEA) and 0.2 M TEA, respectively. The developed anodes are characterized by X-ray diffraction, field emission scanning electron microscope, transmission electron microscopy and X-ray photoelectron spectroscopy. Galvanostatic charge/discharge tests are carried out to evaluate the cycling performance of all the anodes at a constant current density of 680 mA g^− 1 and cyclic voltammetry measurements are performed to characterize the charge/discharge potentials. The Fe₃O₄ NPs/Cu-CAs anode fabricated by 90 s electrodeposition exhibits the best performance with a reversible discharge capacity of 442.96 mAh g^− 1 after 100 cycles at 1 C-rate due to the optimal synergistic effect of crystallinity and reinforcement effect of Cu-CAs substrate. While the better performance of Fe₃O₄ NFs/Cu-CAs anode fabricated by 120 s electrodeposition is attributable to the enhanced surface porosity and reinforcement effect of Cu-CAs. However, the comparison between anodes electrodeposited with 0.1 M and 0.2 M TEA indicates that the reinforcement effect of Cu-CAs plays the dominant role in determining the cycling performance of developed Fe₃O₄/Cu-CAs anodes.