三维纳米硅/多孔碳的储锂性能

摘要

Three-dimensional(3D) silicon/porous carbon composite was synthesized via a one-step facile approach assisted by chemical vapor deposition (CVD),using nano-silicon as active material and acetylene as carbon source.The porous amorphous carbon coated nano-silicon composite with 3D electrical conducting network was characterized by transmission electron microscopy (TEM) and thermogravimetric analysis (TGA).The composite used for lithium storage kept a reversible capacity of 1 270 mAh/g (0.01-1.00 V,200 mA/g) after 100 cycles calculated based on silicon.The improved energy density and cycling performance could be mainly attributed to the in-situ formed porous amorphous carbon layer of the 3D network with better buffering and electron/ion conductivity properties.%以纳米硅粉为活性材料,乙炔为碳源,通过化学气相沉积(CVD)一步法原位制得核壳结构可控的三维硅/多孔碳纳米复合材料.透射电子显微镜(TEM)和热重分析(TGA)结果表明,制备了厚度可控的无定形碳包覆纳米硅颗粒核壳结构,并形成串珠状三维导电网络.以200 mA/g在0.01～1.00 V循环100次,复合材料中硅的可逆比容量保持在1 270 mAh/g.这主要是因为:原位生成的无定形碳可缓冲纳米硅颗粒的体积变化,Li+扩散通道更好;三维网络改善了电子传输性能.