State Key Laboratory of Chemical Resource Engineering, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, PR China.
Phys Chem Chem Phys. 2011 Oct 21;13(39):17818-24. doi: 10.1039/c1cp22378j. Epub 2011 Sep 9.
Graphene nanosheets (GNSs) loading graphene-encapsulated iron microspheres (GEIMs) were fabricated by heat treatment of graphene oxide nanosheets (GONs) with ferric trichloride (FeCl(3)). The special pentagon-hexagonal graphene shells have been produced by precipitation of carbon from metal carbide solutions, thanks to the high reactivity of GONs and ferric nanoparticles dispersing homogeneously between graphene layers. The morphology, structure and elemental composition of GEIMs were investigated by scanning electron microscope, X-ray diffraction and electron energy disperse spectroscope, respectively. The formation mechanism of GEIMs was proposed. Hollow graphene microspheres (HGMs) on the GNSs were obtained with the removal of ferric species in GEIMs. When used as the anode materials for lithium-ion batteries, the almost graphitic HGMs exhibit stable voltage platform at ca. 0.2 V, excellent cycle capability and higher reversible capacity of about 440 mAh g(-1) after 50 cycles and possess great potential application in lithium-ion batteries.
石墨烯纳米片（GNSs）负载石墨烯封装的铁微球（GEIMs）是通过热处理氧化石墨烯纳米片（GONs）与三氯化铁（FeCl（3））制备的。特殊的五边形-六边形石墨烯壳是通过从金属碳化物溶液中沉淀碳而产生的，这要归功于 GONs 的高反应性和铁纳米颗粒在石墨烯层之间均匀分散。通过扫描电子显微镜、X 射线衍射和电子能量色散谱分别研究了 GEIMs 的形貌、结构和元素组成。提出了 GEIMs 的形成机制。通过去除 GEIMs 中的铁物种，在 GNSs 上获得了空心石墨烯微球（HGMs）。当用作锂离子电池的阳极材料时，近乎石墨的 HGMs 在约 0.2 V 时表现出稳定的电压平台，经过 50 次循环后具有优异的循环性能和更高的可逆容量约为 440 mAh g（-1），在锂离子电池中具有很大的潜在应用。
