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

摘要

Magnetite (Fe_3O_4)/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 Fe_3O_4/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 mA g~(-1),420 mA h g~(-1) at 6000 mA g~(-1) and 360 mA h g~(-1) at 9000 mA g~(-1) charge current). Owning to the strong interaction between Fe_3O_4 and EG from in-situ synthesis, it is demonstrated that these properties of this novel Fe_3O_4/EG composite material will be an idea candidate for the negative electrode material of high-current lithium ion battery.