(65i) Facile Preparation of Mesoporous ?-Fe2O3 With Unique Cocoon-Like Hollow Nanostructure for Reversible Lithium Ion Storage

After 20 years of development since the first commercialization of rechargeable lithium ion batteries by Sony in 1991, carbon is still exclusively used as anode materials for lithium ion batteries. However, the theoretical capacity (372mAh g^-1) of graphite is almost achieved now and it becomes a bottleneck to further increase lithium-ion storage capacity using carbon. Carbon-alternative materials with higher capacity are currently being extensively explored to meet the increasing demand for energy in mobile electronic devices, electric vehicles and energy storage in grid. Transition metal oxides receive increasing attention as carbon-alternatives because of their much higher theoretical capacity. For example, α-Fe₂O₃ with a theoretical capacity of 1007 mAh g^-1 is a promising candidate. Compared to other transition metal oxides, α-Fe₂O₃ is outstanding in terms of low cost, abundance, ease of fabrication, and environmental benignity. However, the poor cyclability caused by volume change during the insertion /extraction of Li ions and poor conductivity is the main challenge. Our strategy is to design and tailor α-Fe₂O₃ at nanoscale with structure control to improve their electrochemical performance. In this presentation, the strategy to facilely prepare mesoporous α-Fe2O3 with unique cocoon-like hollow nanostructure as anode materials will be reported. The formation mechanism is revealed by extensive characterization by FESEM, TEM and XRD for samples prepared under different controlled conditions. The improved electrochemical performance in reversible lithium ion storage will be discussed.