Amorphous Vanadium Oxide Matrixes Supporting Hierarchical Porous Fe sub(3)O sub(4)/Graphene Nanowires as a High-Rate Lithium Storage Anode

Developing electrode materials with both high energy and power densities holds the key for satisfying the urgent demand of energy storage worldwide. In order to realize the fast and efficient transport of ions/electrons and the stable structure during the charge/discharge process, hierarchical porous Fe sub(3)O sub(4)/graphene nanowires supported by amorphous vanadium oxide matrixes have been rationally synthesized through a facile phase separation process. The porous structure is directly in situ constructed from the FeVO sub(4).1.1H sub(2)Oraphene nanowires along with the crystallization of Fe sub(3)O sub(4) and the amorphization of vanadium oxide without using any hard templates. The hierarchical porous Fe sub(3)O sub(4)/VO sub(x)/graphene nanowires exhibit a high Coulombic efficiency and outstanding reversible specific capacity (1146 mAh g super(-1)). Even at the high current density of 5 A g super(-1), the porous nanowires maintain a reversible capacity of similar to 500 mAh g super(-1). Moreover, the amorphization and conversion reactions between Fe and Fe sub(3)O sub(4) of the hierarchical porous Fe sub(3)O sub(4)/VO sub(x)/graphene nanowires were also investigated by in situ X-ray diffraction and X-ray photoelectron spectroscopy. Our work demonstrates that the amorphous vanadium oxides matrixes supporting hierarchical porous Fe sub(3)O sub(4)/graphene nanowires are one of the most attractive anodes in energy storage applications. Keywords: Iron oxides; vanadium oxides; graphene; hierarchical porous nanowires; lithium ion battery