锂离子电池硅/碳复合网状整体电极的制备与性能

A binder-free web-like silicon-carbon nanofiber-graphene hybrid membrane for use as the anode of a lithium-ion battery

  • 摘要: 基于静电喷雾沉积技术制备了硅-纳米炭纤维-石墨烯杂化膜(Si/CNF/G),其中纳米硅颗粒包覆在多孔炭基体中,由纳米硅和多孔炭组成的二次结构被镶嵌在由纳米炭纤维和石墨烯组成的三维交联炭网络中,最终构成无粘结剂的硅/碳复合整体电极。Si/CNF/G三维杂化膜用作锂离子电池电极时,表现高的可逆比容量、长的循环寿命和良好的倍率性能。0.2 A·g-1恒定电流密度下,首次可逆比容量为957 mAh·g-1,经100圈循环容量保持率为74.4%;2 A·g-1恒定电流密度下,可逆比容量为539 mAh·g-1。多孔炭基体可有效缓冲硅的体积变化,促进形成稳定的固态电解质界面;纳米炭纤维和石墨烯构建的三维炭网络既稳定了电极的整体结构,又可为电子和离子提供快速传输通道。

     

    Abstract: A binder-free silicon-carbon nanofiber-graphene (Si-CNF-G) hybrid membrane was prepared by embedding Si particles encapsulated in a porous carbon in a cobweb-like carbon scaffold composed of CNFs and G nanosheetsproduced using the coaxial electrospraying method. The binder-free Si-CNF-G electrode delivered an initial reversible specific capacity of 957 mAh·g-1 with a retention of 74.4% after 100 cycles at 0.2 A·g-1, and a rate capability of 539 mAh·g-1 at 2 A·g-1, which was much better than that of a Si electrode. This can be attributed to the fact that the porous carbon matrix was able to buffer the large volume expansion and contraction of Si during charging and discharging, and that the interconnected carbon scaffold not only created efficient pathways for electron conduction and ion transfer, but also improved the structural stability of the whole electrode.

     

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