alpha-Fe(2)o(3) Submicron Spheres with Hollow and Macroporous Structures as High-Performance Anode Materials for Lithium Ion Batteries

Abstract

alpha-Fe2O3 submicron spheres with different internal structures were prepared as anode materials for lithium ion batteries (LIBs). Using sulfonated polystyrene (SPS) microspheres as a template, we designed a hollow and macroporous alpha-Fe2O3 particle structure. The sulfonation degree of polystyrene (SPS) microspheres was controlled by sulfonation reaction time in the range of 24-36 h. After introducing Fe metal precursors by adsorption of ferrous ions into the SPS particles and adding a reduction agent, alpha-Fe2O3 submicron spheres with hollow and macroporous structures were obtained by heat treatment in an air atmosphere. The internal structure of particles was characterized by scanning electron microscopy, transmission electron microscopy, focused ion beam-scanning electron microscopy, and X-ray diffraction. The electrochemical properties of the hollow and macroporous alpha-Fe2O3 composite electrodes were investigated by galvanostatic cycling at both constant and variable current rates. The alpha-Fe2O3 submicron spheres with hollow and macroporous structures exhibited excellent cyclability and rate capability. Electrical impedance spectroscopy was employed to prove the structural effects on the cell performances.