Facile synthesis of iron-based compounds as high performance anode materials for Li-ion batteries

Abstract

Iron oxide@C composites and lithium ferrites were synthesized by a cotton-template method as anode materials for Li-ion batteries. α-Fe₂O₃@C composites with 3-D porous hollow secondary structures were prepared by directly burning the cotton containing the iron salt (FeCl₃ or Fe(NO₃)₃) in air, and the Fe₃O₄@C composites with similar structures were obtained by annealing α-Fe₂O₃@C under a N₂ atmosphere. α-LiFeO₂ and α-LiFe₅O₈ particles with sizes of 100–500 nm were also prepared using a similar method. Electrochemical measurements showed that all these samples demonstrated good electrochemical performances as Li-ion battery anodes, especially α-Fe₂O₃@C derived from Fe(NO₃)₃, which delivers a high reversible capacity of 990 mA h g⁻¹ at 100 mA g⁻¹ after 50 cycles. Both the porous hollow secondary structure and the suitable amount of amorphous carbon are significant for the electrochemical performances of the iron oxide@C composites. Such a method is simple, rapid and inexpensive and may facilitate the preparation of other high performance electrode materials with porous hollow structures.