Porous 2D Silicon/CNTs/Graphene free-standing composites were prepared via a solution-based self-assembly process with vapor post-treatment and applied as anodes for lithium-ion batteries. Silicon nanoparti-cles (~50 nm) as active materials were uniformly embedded between graphene sheets without agglomeration. Gra-phene was used as electrical conductive carbon matrix to form a 2D conductive network for electrons. CNTs, with high electrical conductivity and mechanical strength, formed into a scaffold along with graphene to enhance the conductivity and mechanical properties of the carbon matrix. After vapor post-treatment, CNTs supported graphene film transferred from a tightly stacked film to a loose packed porous film. The porous structure of this free-standing composite anode provides large internal space to accommodate volumetric changes and provide abundant channels for diffusion of Li+, fast electron transport and easy penetration of electrolyte. The composites exhibite an outstanding rate performance and cyclic stability, delivering a capacity of 600 mAh/g at 4/A g and 1010 mAh/g after 100 cycles at 0.1 A/g. They also show high structure and mechanical stability after cycle test. It provides an exciting pathway to the rational design and fabrication of silicon anode and 2D graphene matrix for applications in lithium-ion batteries.%通过真空驱动自组装法及蒸汽处理得到结构疏松的硅/碳纳米管/石墨烯自支撑负极材料(Si/CNTs/GP).纳米硅颗粒(50 nm)为活性物质,均匀分布在石墨烯片层结构中间;石墨烯作为碳基体,通过自组装构筑形成二维导电网络;碳纳米管(CNTs)具有超高导电性和良好的力学强度,它通过吸附作用均匀分布在石墨烯基体上形成导电的支撑网络结构.经过蒸汽处理后,石墨烯层间距明显增大,层与层之间不再是紧密堆叠的结构,而是形成一种疏松、褶皱、内部空隙丰富的片层结构.Si/CNTs/GP负极材料中丰富的内部空穴和贯穿孔洞,提供了材料很高的比表面积,能有效提高电解液对材料的浸润性,极大缩短了离子传输距离.同时这些内部空穴也有效缓冲硅充放电时的体积膨胀,提高了材料的结构稳定性和电化学性能.该负极材料在4 A/g的大电流密度下容量维持在600 mAh/g,表现出良好的大电流循环稳定性能.
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