基于共价键作用的四氧化三铁-还原氧化石墨烯复合材料的合成及其储锂性能

Ferric Oxide-reduced Graphene Oxide Composite Material: Synthesis Based on Covalent Binding and Its Lithium-storage Property

采用溶剂热法制备单分散的Fe_3O_4微球,对其表面进行包覆SiO_2和氨基化处理,再与氧化石墨烯复合,化学还原后得到Fe_3O_4-W-RGO复合材料。SEM和TEM照片显示,SiO_2均匀包覆在Fe_3O_4微球(直径~440 nm)表面形成Fe_3O_4@SiO_2核壳微球,紧密束缚于RGO纳米片表面。XRD测试结果表明Fe_3O_4微球结晶度好、纯度高。电化学性能测试结果表明:在0.01~3.00 V电压范围和0.1C倍率下,Fe_3O_4-W-RGO复合材料的首次放电容量为1246 m Ah/g,100次循环后保持830 m Ah/g;在2C倍率下放电容量达到484 m Ah/g,具有较好的倍率性能和循环性能。

Monodispersed ferroferric oxide（Fe3O4） microspheres were prepared by a solvo-thermal method at first. They were coated with a thin layer of silica, and modified with amino groups. These updated microspheres were mixed with graphene oxide（GO） followed by a chemical reduction to yield Fe3O4-W-RGO. The sample was characterized with scanning electron microscopy（SEM） and transition electron microscopy（TEM）. Fe3O4 microspheres（-440 nm in diameter） are proved to be surface-coated by a SiO2 layer homogeneously to afford Fe3O4@SiO2 core-shell microspheres, tightly bound to reduced graphene oxide（RGO） nanosheets. From X-ray diffraction（XRD） patterns, Fe3O4 microspheres display good crystallinity and high purity. Results of electrochemical measurements indicate that Fe3O4-W-RGO sample can deliver an initial capacity of 1246 m Ah/g at 0.1 C rate over 0.01 V-3.00 V（vs. Li＋/Li）, and retain 830 m Ah/g after 100 cycles. Even at 2 C rate, it can still deliver a capacity of 484 m Ah/g. All results suggest that Fe3O4-W-RGO composite material possesses good rate capability and cycling performance when used as anode material for lithium-ion batteries.