Self-assembly of hierarchical Fe3O4 microsphere/graphene nanosheet composite: towards a promising high-performance anode for Li-ion batteries

Abstract

A hierarchical Fe₃O₄ microsphere/graphene nanosheet (H-Fe₃O₄-MS/GNS) composite has been synthesized by a facile one-pot solvothermal route. The Fe₃O₄ microspheres uniformly decorated the surface of the two dimensional GNS. Each Fe₃O₄ microsphere possesses a hierarchical and porous structure, which is composed of Fe₃O₄ nanoparticles with a diameter of about 10 nm. As an anode material for Li-ion batteries, the H-Fe₃O₄-MS/GNS composite shows high specific capacity and good cycling stability (1171.6 mA h g⁻¹ at 200 mA g⁻¹ and 940.4 mA h g⁻¹ at 500 mA g⁻¹ up to 70 cycles), reduced voltage hysteresis, as well as enhanced rate capability. The improved electrochemical performance can be attributed to the combination of the conductivity, confinement and dispersion effects of GNS and the porous hierarchical structure of the Fe₃O₄ microsphere.