【摘要】 将柠檬酸和Super P （SP）作为碳源用喷雾干燥技术制备出具有分级结构的类球形MgFe₂O₄/C （MFO/C）复合材料,使用场发射扫描电子显微镜（FESEM）、透射电子显微镜（TEM）、X射线粉末衍射仪（XRD）、X射线光电子能谱仪（XPS）和电化学测试等手段表征了样品的形貌、结构和电化学性能。结果表明,在电流密度为0.5 C (500 mA·g^-1)的条件下这种复合材料的首次放电比容量为1162.7 mAh·g^-1,200次循环后比容量稳定在约734.5 mAh·g^-1。在电流密度为1C (1000 mA·g^-1)条件下,200次循环后比容量仍保持在约580.4 mAh·g^-1。具有优异的循环和倍率性能的原因,可能是SP和柠檬酸分解生成的晶粒间碳形成了良好的导电网络,使材料的导电性提高并缓解了在连续充放电过程中活性物质的团聚和体积膨胀。更多还原

【Abstract】 The spherical composite of MgFe2 O4/C（MFO/C） with hierarchical structure was prepared via spray drying technology with citric acid and Super P（SP） as carbon source. The morphology, structure and electrochemical performance of the MFO/C were characterized by field emission scanning electron microscopy（FESEM）, transmission electron microscopy（TEM）, X-ray powder diffractometer（XRD）,X-ray photoelectron spectrometer（XPS） and electrochemical measurements. Results show that the first discharge capacity of the material is 1162.7 mA·g^-1 and the reversible specific capacity stabilizes at about 734.5 mA·g^-1 after 200 cycles when the current density is 0.5 C(500 mA·g^-1). Even at a higher current density of 1 C(1000 mA·g^-1), the reversible specific capacity stabilizes at about 580.4 mA·g^-1 after200 cycles. The excellent cycling stability and rate performance can be attributed to the emerging of a su-perior conductive network, which composed of SP and the intergranular carbon formed due to the decomposition of citric acid, as a result, the conductivity of the spherical composite of MgFe2 O4/C could be effectively enhanced, while the aggregation and volumetric expansion of the active particles could also be alleviated in the continuous charge and discharge process.更多还原