Fabrication of Fe3 O4 Dots Embedded in 3D Honeycomb-Like Carbon Based on Metallo-Organic Molecule with Superior Lithium Storage Performance

Abstract

A novel metallo-organic molecule, ferrocene, is selected as building block to construct Fe₃ O₄ dots embedded in 3D honeycomb-like carbon (Fe₃ O₄ dots/3DHC) by using SiO₂ nanospheres as template. Unlike previously used inorganic Fe₃ O₄ sources, ferrocene simultaneously contains organic cyclopentadienyl groups and inorganic Fe atoms, which can be converted to carbon and Fe₃ O₄ , respectively. Atomic-scale Fe distribution in started building block leads to the formation of ultrasmall Fe₃ O₄ dots (≈3 nm). In addition, by well controlling the feed amount of ferrocene, Fe₃ O₄ dots/3DHC with well-defined honeycomb-like meso/macropore structure and ultrathin carbon wall can be obtained. Owing to unique structural features, Fe₃ O₄ dots/3DHC presents impressive lithium storage performance. The initial discharge and reversible capacities can reach 2047 and 1280 mAh g^-1 at 0.05 A g^-1 . With increasing the current density to 1 and 3 A g^-1 , remarkable capacities of 963 and 731 mAh g^-1 remain. Moreover, Fe₃ O₄ dots/3DHC also has superior cycling stability, after a long-term charge/discharge for 200 times, a high capacity of 1082 mAh g^-1 can be maintained (80% against the capacity of the 2nd cycle).

Keywords: Fe3O4 dot; crosslink; ferrocene; honeycomb-like carbon; lithium ion battery.