TiO2 modified α-Fe2O3 pompon-like hollow sphere as the anode material for lithium-ion batteries with mixed lithiation mechanisms

Abstract

By using a self-sacrificing template method, TiO2/α-Fe2O3 pompon-like hollow sphere composite can be produced. The morphology, composition, valence state, and the lithiation mechanism of the composite have been carefully investigated. As a new anode material for lithium-ion batteries (LIBs), it shows a specific capacity of above 970 mAh g−1 after 120 cycles at a current rate of 200 mA g−1, which is much better than bulk α-Fe2O3 or α-Fe2O3 microspheres. The obviously amelioration may be attribute to the incorporation of a small amount of TiO2 (~ 5%) in the composite and the morphology of the TiO2/α-Fe2O3 heterostructure, which may be associated with the synergetic effects between two kinds of lithium storage mechanism. By using NMR to characterize lithiated sample with different charge-discharge states, a mixed mechanism has been proved. The strategy above is expected to be extended to improve the electrochemical properties of other metal oxides with various lithiation mechanisms for LIBs applications.