Magnetite/graphene nanosheet composites: Interfacial interaction and its impact on the durable high-rate performance in lithium-ion batteries

Abstract

We explore in-depth the interfacial interaction between Fe 3 O 4 nanoparticles and graphene nanosheets as well as its impact on the electrochemical performance of Fe 3 O 4 / graphene anode materials for lithium-ion batteries. Fe 3 O 4 /graphene hybrid materials are prepared by direct pyrolysis of Fe(NO 3) 3 ·9H 2 O on graphene sheets. The interfacial interaction between Fe 3 O 4 and graphene nanosheets is investigated in detail by thermogravimetric and differential scanning calorimetry analysis, Raman spectrum, X-ray photoelectron energy spectrum and Fourier transform infrared spectroscopy. It was found that Fe 3 O 4 nanoparticles disperse homogeneously on graphene sheets, and form strong covalent bond interactions (Fe-O-C bond) with graphene basal plane. The strong covalent links ensure the high specific capacity and long-period cyclic stability of Fe 3 O 4 /graphene hybrid electrodes for lithium-ion batteries at high current density. The capacity keeps as high as 796 mAhg -1 after 200 cycles without any fading in comparison with the first reversible capacity at the current density of 500 mAg -1 (ca. 0.6 C). At 1 Ag -1 (ca. 1.3 C), the reversible capacity attains ca. 550 mAhg -1 and 97% of initial capacity is maintained after 300 cycles. This work reveals an important factor affecting the high-rate and cyclic stability of metal oxide anode, and provides an effective way to the design of new anode materials for lithium-ion batteries. © The Royal Society of Chemistry 2011.