静电自组装方法合成的具有多孔三维网络结构的Fe_3O_4/石墨烯复合材料作为高性能锂离子电池负极材料(英文)

Fe_3O_4/Graphene Composites with a Porous 3D Network Structure Synthesized through Self-Assembly under Electrostatic Interactions as Anode Materials of High-Performance Li-Ion Batteries

采用静电自组装方法,分两步合成Fe(OH)3/GO前驱体(GO:氧化石墨烯),再通过水热反应和600°C高纯氮气气氛下煅烧,获得了Fe3O4/石墨烯复合材料.通过X射线衍射(XRD)、扫描电镜(SEM)、高分辨透射电镜(HRTEM)、拉曼(Raman)光谱等多种分析,发现该复合材料具有三维多孔石墨烯网络结构.把合成的这种Fe3O4/石墨烯复合材料作为锂离子电池负极材料,电化学测试结果表明其具有优良的电化学性能:首次放电容量为1390 mAh·g-1,50次循环后容量为819 mAh·g-1.通过对比实验表明,三维石墨烯网络结构的形成对复合材料的电化学循环稳定性起着关键作用.

Fe3O4/graphene composites with a conductive, porous three-dimensional （3D） graphene network were synthesized through a facile method. In the preparation process, Fe（OH）3 colloid was formed in situ by adding FeCI3 solution to a boiling graphene oxide （GO） suspension, with Fe（OH）JGO precipitated because of the electrostatic interaction between the two components. The precipitate was separated and added to a second GO suspension to achieve additional GO encapsulation. This self-assembled Fe（OH）JGO precursor was then hydrothermally and heat treated, resulting in the formation of Fe3O4/graphene composites. X-ray diffraction （XRD）, scanning electron microscopy （SEM）, high-resolution transmission electron microscopy （HRTEM）, and Raman spectroscopy results revealed that the Fe30,/graphene composites possess a favorable 3D porous graphene network embedding 50- to 100-nm-sized Fe30, nanoparticles. The Fe3O4/graphene composites exhibit good electrochemical performance as an anode material for Li-ion batteries. The electrode composed of the Fe3O4/graphene composite delivered a capacity of 1390 mAh·g^-1 for the first lithiation and retained a capacity of 819 mAh·g^-1 after 50 cycles. The electrodes also exhibited good rate capability. The present results demonstrate that the electrochemical performance of the Fe3O4/graphene composite is highly sensitive to its preparation procedure and to the resulting nanostructure. Each of the four preparation procedures was experimentally shown to be important for achieving the final nanostructure and good electrochemical performance. A formation mechanism for the Fe3O4/graphene composite is also proposed.