Fabrication of Core–Shell α-Fe2O3@ Li4Ti5O12 Composite and Its Application in the Lithium Ion Batteries

In this work, a novel carbon-free core-shell α-iron oxide (α-Fe2O3)@ spinel lithium titanate (Li4Ti5O12, LTO) composite has been synthesized via a facile hydrothermal process. Element mapping confirmed the core-shell structure of α-Fe2O3@LTO. The effects of various experimental parameters, including thickness of TiO2 coating, reaction temperature, and time on the morphologies of the resulted products, were systematically investigated. The electrochemical measurements demonstrate that uniform α-Fe2O3 ellipsoids are coated with LTO to avoid forming a solid electrolyte interface (SEI) layer, to reduce initial capacity loss, and to improve the reversibility of α-Fe2O3 for Li ion storage. Compared with naked α-Fe2O3 ellipsoids, the α-Fe2O3@LTO composites exhibit lower initial capacity loss, higher reversible capacity, and better cycling performance for lithium storage. The electrochemical performance of α-Fe2O3@LTO composite heavily depends on the thickness and density of LTO coating shells. The carbon-free coating of LTO is highly effective in improving the electrochemical performance of α-Fe2O3, promising advanced batteries with high surface stability and excellent security.