LAUSR

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 Fe2O3 hierarchical microcube. Due to the cross-link between PEI and iron ions, the formed Fe2O3 nanorods tightly connect with each other and form hierarchical structure. After the carbonization of PEI, hierarchical porous Fe2O3 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.