Facile and large-scale fabrication of hierarchical ZnFe2O4/graphene hybrid films as advanced binder-free anodes for lithium-ion batteries

Abstract

Hierarchical ZnFe₂O₄/graphene (ZFO/GN) hybrid films have been successfully fabricated by a facile one-step cathodic electrophoretic deposition (EPD) of graphene oxide, Fe(NO₃)₃, and Zn(NO₃)₂ colloidal suspension on copper foils and subsequent thermal annealing. The obtained ZnFe₂O₄ nanoparticles are homogeneously dispersed and anchored between the graphene sheets, forming a unique sheet-like hybrid nanostructure. It was found that different ZnFe₂O₄ morphologies and their mass content in the hybrid films could be easily controlled by varying the concentration of the precursor. The resulting binder-free ZFO/GN hybrid films were directly evaluated as anodes for rechargeable lithium half-cells without adding any polymer binder or conductive additives. Among these, the ZFO/GN hybrid film with 55.88 wt% graphene exhibits superior lithium storage performance with a high specific reversible capacity (910.21 mA h g⁻¹ at a high current density of 200 mA g⁻¹), excellent rate capability (more than 510 mA h g⁻¹ even at the specific current of 3200 mA g⁻¹), and good electrochemical cyclic stability (stable at ∼881 mA h g⁻¹ after 200 cycles).