Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063, China.
Nanoscale. 2013 Oct 21;5(20):9684-9. doi: 10.1039/c3nr03484d.
Novel hematite@graphene composites have been successfully synthesized by a one-pot surfactant governed approach under mild wet-chemical conditions. A series of characterizations including X-ray diffraction (XRD), Raman spectrum, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicated that the hematite nanoparticles with relatively uniform size were encapsulated by graphene layers and were able to form core-shell nanostructures. The electrochemical properties of hematite@graphene core-shell nanostructures as anodes for lithium-ion batteries were evaluated by galvanostatic charge-discharge and AC impedance spectroscopy techniques. The as-prepared hematite@graphene core-shell nanostructures exhibited a high reversible specific capacity of 1040 mA h g(-1) at a current density of 200 mA g(-1) (0.2 C) after 180 cycles and excellent rate capability and long cycle life. Furthermore, a reversible capacity as high as 500 mA h g(-1) was still achieved after 200 cycles even at a high rate of 6 C. The electrochemical test results show that the hematite@graphene composites prepared by the one-pot wet chemical method are promising anode materials for lithium-ion batteries.
通过在温和的湿化学条件下采用一锅表面活性剂控制的方法，成功合成了新型赤铁矿@石墨烯复合材料。一系列的表征包括 X 射线衍射（XRD）、拉曼光谱、扫描电子显微镜（SEM）和透射电子显微镜（TEM）表明，相对均匀尺寸的赤铁矿纳米颗粒被石墨烯层包裹，并能够形成核壳纳米结构。通过恒电流充放电和交流阻抗谱技术评估了作为锂离子电池负极的赤铁矿@石墨烯核壳纳米结构的电化学性能。在 180 次循环后，在 200 mA g(-1)（0.2 C）的电流密度下，所制备的赤铁矿@石墨烯核壳纳米结构表现出高达 1040 mA h g(-1)的高可逆比容量，并且具有优异的倍率性能和长循环寿命。此外，即使在 6 C 的高倍率下，经过 200 次循环后仍可获得高达 500 mA h g(-1)的可逆容量。电化学测试结果表明，通过一锅湿化学法制备的赤铁矿@石墨烯复合材料是锂离子电池有前途的负极材料。
