State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, WUT-Harvard Joint Nano Key Laboratory, Wuhan University of Technology , Wuhan 430070, China.
Nano Lett. 2014 Nov 12;14(11):6250-6. doi: 10.1021/nl5025694. Epub 2014 Oct 20.
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 Fe3O4/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 FeVO4·1.1H2O@graphene nanowires along with the crystallization of Fe3O4 and the amorphization of vanadium oxide without using any hard templates. The hierarchical porous Fe3O4/VOx/graphene nanowires exhibit a high Coulombic efficiency and outstanding reversible specific capacity (1146 mAh g(-1)). Even at the high current density of 5 A g(-1), the porous nanowires maintain a reversible capacity of ∼500 mAh g(-1). Moreover, the amorphization and conversion reactions between Fe and Fe3O4 of the hierarchical porous Fe3O4/VOx/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 Fe3O4/graphene nanowires are one of the most attractive anodes in energy storage applications.
开发兼具高能量密度和功率密度的电极材料是满足全球储能迫切需求的关键。为了实现离子/电子的快速高效传输以及在充放电过程中的稳定结构，通过简便的相分离过程，合理合成了由无定形氧化钒基体支撑的分级多孔 Fe3O4/石墨烯纳米线。多孔结构是直接从 FeVO4·1.1H2O@石墨烯纳米线原位构建的，伴随着 Fe3O4 的结晶和氧化钒的非晶化，而无需使用任何硬模板。分级多孔 Fe3O4/VOx/石墨烯纳米线表现出高库仑效率和出色的可逆比容量（1146 mAh g-1）。即使在 5 A g-1 的高电流密度下，多孔纳米线仍保持约 500 mAh g-1 的可逆容量。此外，通过原位 X 射线衍射和 X 射线光电子能谱研究了分级多孔 Fe3O4/VOx/石墨烯纳米线中 Fe 和 Fe3O4 之间的非晶化和转化反应。我们的工作表明，支撑分级多孔 Fe3O4/石墨烯纳米线的无定形氧化钒基体是储能应用中最具吸引力的阳极之一。
