Facile synthesis of Fe₃O₄/NiFe₂O₄ nanosheets with enhanced Lithium-ion storage by one-step chemical dealloying

Fe₃O₄/NiFe₂O₄ nanosheets as anode materials for lithium-ion batteries have been successfully prepared by a facile one-step dealloying method of Al–Fe–Ni alloy precursor. Herein, the XRD results and XPS spectra indicated that the product consists of cubic NiFe₂O₄ and Fe₃O₄. Scanning electronic microscopy and transmission electron microscopy images showed the homogenous distribution of Fe₃O₄/NiFe₂O₄ in the quasi-hexagonal nanosheets rather than irregular clusters. Besides nanostructures, their electrochemical performances were also enhanced due to the doping of nickel when comparing with the Fe₃O₄ obtained by dealloying Al–Fe precursor. Cycling and rate tests elicited the DAFN has the Fe₃O₄/NiFe₂O₄ product exhibit a higher initial capacity of ~ 1437 mAh g⁻¹ at 200 mA g⁻¹ and modified rate performances, especially they hold a doubled reversible capacity over 500 mAh g⁻¹ after 750 times cycling at 200 mA g⁻¹. Cyclic voltammetry, charge–discharge tests and electrochemical impedance spectra measurements further demonstrated the reinforced initial capacity and cycling stability of the DAFN could be associated with the shortened diffusion pathways and synergistic effect of Fe₃O₄ and NiFe₂O₄. The facile and low-cost processing method accompanied with the well-performed product exhibit a promising prospect in the application of lithium-ion storage.