In-situ synthesis of magnetite/expanded graphite composite material as high rate negative electrode for rechargeable lithium batteries

Magnetite (Fe3O4)/expanded graphite (EG) composite material is prepared through the oxidation progress of ferrocene-graphite intercalation compound in acetone solution. The reactions occur in this system and lead to in-situ synthesis of the composite with nanosized magnetite and expanded graphite. Due to the lithium insertion/extraction experiment, the Fe3O4/EG composite material shows high reversible capacities (ca. 720 mA h g(-1) at 120 mA g(-1) charge current) and excellent rate performances (ca. 630 mA h g(-1) at 600 rnA g(-1), 420 mA he at 6000 mA g(-1) and 360 mA h g(-1) at 9000 mA g(-1) charge current). Owning to the strong interaction between Fe3O4 and EG from in-situ synthesis, it is demonstrated that these properties of this novel Fe3O4/EG composite material will be an idea candidate for the negative electrode material of high-current lithium ion battery. (C) 2012 Elsevier B.V. All rights reserved.