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.
Keywords: graphene; iron oxide; phase boundary; plasma; sodium-ion battery.