Rationally designed layer-by-layer structure of Fe^sub 3^O^sub 4^ nanospheres@MWCNTs/graphene as electrode for lithium ion batteries with enhanced electrochemical performance

Ferroferric oxide (Fe3O4), a potential anode material, has been limited by the intrinsically low electrical conductivity and dramatic volume variations resulting in significant capacity decay. Here, the Fe3O4 nanospheres (Fe3O4NS) integrated with multiwalled carbon nanotubes (MWCNTs) and reduced graphene oxide (r-GO) are used to construct a novel layer-by-layer structure via electrostatic interaction self-assembly and vacuum filtration processes. The Fe3O4 NS are closely attracted to the MWCNTs network, and the r-GO layer likes a scaffold enabling to obtain a paper-like electrode. The multilayer electrode exhibits impressive capacity of 720 mAh g-1 after 100 cycles at a current density 0.2 A g-1, even after 300 cycles, the capacity is still above 420 mAh g-1 at 3.2 A g-1. The multilayer structure can accommodate the volume change that occurs during cycling, and maintain the structural stability during long-term cycling, which result in their superior electrochemical properties.