Rational engineering NiMoO4 nanosheets or Mn3O4 nanowires on Fe2O3 microdiscs as novel hierarchical anodes for high-performance lithium-ion batteries.

Since current graphite-based lithium-ion battery anode has a low theoretical capacity, the development of high-performance lithium-ion battery is severely restricted. Here, novel hierarchical composites composing of microdisc and the secondarily grown nanosheets and nanowires are developed, taking NiMoO4 nanosheets and Mn3O4 nanowires growing on Fe2O3 microdiscs as demonstrating examples. The growth processes of the hierarchical structures have been investigated by adjusting a series of preparation conditions. The morphologies and structures have been characterized by using scanning electron microscopy, transmission electron microscope and X-ray diffraction. Fe2O3@Mn3O4 composite-based anode displays a capacity of 713 mAh g-1 after 100 cycles at 0.5 A g-1 with a high Coulombic efficiency. A good rate-performance is also achieved. Fe2O3@NiMoO4 anode delivers 539 mAh g-1 after 100 cycles at 0.5 A g-1, which is obviously higher than that of pure Fe2O3. The hierarchical structure is conducive to improve the transport of electrons and ions, and provide numerous active sites, thus significantly enhancing the electrochemical performance. Moreover, the electron transfer performance is investigated by using density functional theory calculations. It is expected the findings presented here and the rational engineering of nanosheets/nanowires on microdiscs would be applicable for developing many other high-performance energy-storage composites.