石墨烯
材料科学
阳极
扫描电子显微镜
硅
复合数
化学工程
多孔硅
法拉第效率
化学气相沉积
氧化物
碳纤维
锂(药物)
拉曼光谱
透射电子显微镜
复合材料
纳米技术
多孔性
电极
化学
光电子学
冶金
物理化学
内分泌学
医学
工程类
物理
光学
作者
Yuehua Huang,Jing Luo,Jiao Peng,Minhao Shi,Xingxing Li,Xianyou Wang,Baobao Chang
标识
DOI:10.1016/j.est.2019.101075
摘要
The porous silicon-graphene-carbon (SGC) composite is prepared by freeze-drying and chemical vapor deposition (CVD) process with commercially available nano-silicon, phenolic resin and graphene oxide as raw materials. The self-assembly process makes the nano-silicon into a porous structure and uniform recombination with the graphene oxide, and finally a nano-carbon layer is coated on the surface of the SGC composite by a CVD process. The composition, morphology and pore properties of SGC composite are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and pore size analysis. The nano-carbon layer on the surface of the SGC is examined by transmission electron microscopy (TEM) and Raman spectrometer. The contents of C, Si and O in precursor and SGC are analyzed by X-Ray Fluorescence (XRF), and the electrochemical performances of composite material are analyzed by half-cell and full-cell experiments. The results show that the SGC composite is porous structure with the average pore size of 20–30 nm, and the surface of the porous silicon-graphene is coated by a thickness of 5 nm carbon layers. The reversible capacity and initial coulombic efficiency (ICE) of the SGC are 2180 mAh g−1 and 79.3%. The capacity retention is higher than 70.1% after 100 charge/discharge cycles by the half-cell experiment; and the capacity of the composite anode is still as high as 550 m Ah g−1 after 820 charge/discharge cycles by full-cell experiment. Therefore, the structure design strategy of the composite is beneficial to buffer the volume effect of nano-silicon, prevent iterative growth of the SEI film and boost the electrochemical performances.
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