Hierarchical porous Fe 2 O 3 assisted with graphene-like carbon as high-performance lithium battery anodes

Abstract Compared with bottom-up method of self-assembly, top-down technology (such as surface-protected etching strategy) is much more efficient and high-yield to build a stable hierarchical electrode for lithium battery. Herein, a water-soluble polymer of polyethyleneimine (PEI) is used as structure protector to achieve Fe 2 O 3 hierarchical microcube. Due to the cross-link between PEI and iron ions, the formed Fe 2 O 3 nanorods tightly connect with each other and form hierarchical structure. After the carbonization of PEI, hierarchical porous Fe 2 O 3 microcube assisted with graphene-like carbon can be prepared, which shows very good electrochemical performance. In short, the hybrid electrode possesses high reversible capacitance of 892 mA h/g at 0.5 A/g, good rate capability (the capacity robustly recovered after 710 cycles at various current rates), and cycling stability (96.2% capacity retention after 550 cycles at 3 A/g, trivial 0.007% capacity decay per cycle). This strategy can be widely used in the synthesis of other hierarchical structure materials with excellent performance.