Low electrical conductivity severely limits the application of Fe₂O₃ in lithium- and sodium-ion batteries. In respect of this, we design and fabricate Fe₂O₃/Fe₃O₄ nano-aggregates anchored on nitrogen-doped graphene as an anode for sodium-ion batteries with the assistance of microwave plasma. The highly conductive Fe₃O₄ in the composite can function as a highway of electron transport, and the voids and phase boundaries in the Fe₂O₃/Fe₃O₄ heterostructure facilitate Na⁺ ion diffusion into the nano-aggregates. Furthermore, the Fe–O–C bonds between the nano-aggregates and graphene not only stabilize the structural integrity, but also enhance the charge transfer. Consequently, the Fe₂O₃/Fe₃O₄/NG anode exhibits specific capacity up to 362 mAh g⁻¹ at 100 mA g⁻¹, excellent rate capability, and stable long-term cycling performance. This multi-component-based heterostructure design can be used in anode materials for lithium- and sodium-ion batteries, and potential opens a new path for energy storage electrodes.