静电纺丝法制备Si/C复合负极材料及其性能表征

Synthesis and Characterization of Si/C Composite Anode by Electrostatic Spinning Method

以聚乙烯吡咯烷酮（PVP）作为高分子聚合物配体，采用静电纺丝法制备了Si／C复合负极材料。利用PVP高温烧结形成的碳作为体积缓冲骨架，有效地解决了硅在循环过程中的体积膨胀和粉化问题。采用x射线衍射rXRD）、拉曼光谱（Raman）和扫描电子显微镜（SEM）对复合材料的晶体结构及微观形貌进行了研究。结果表明，材料整体呈纤维状分布，纤维直径300～400nm，Si粒子以“麦穗状”均匀地分布在由无定形碳构成的纤维上。电化学测试结果表明，复合材料首次充放电的不可逆容量为294．9mAh／g，是由于电极与电解液界面间固态电解质（SEI）膜的形成所致。另外，复合材料在低倍率（0．1c、0．2C和0．50和高倍率（1．0C和2．0℃）下均具有较高的库伦效率及较好的循环稳定性。

Si/C composite anode material was successfully fabricated by an electrospinning method using PVP as macromolecule polymer collocation. The carbon derived from sintering PVP at high temperature plays a role in buff- eting size skeleton of silicon, which can effectively improve the volume expansion and pulverization problem of sili- con at charge-discharge. The structure and morphology of the as-prepared samples were characterized by X-ray dif- fraction （XRD）, Raman spectrum （Raman） and scanning electron microscope （SEM）. The results show that the distri- bution of composite material is fibrous with diameter in the range of 300-400 nm. A ＂wheat like＂ structure is formed by Si particles distributed on the amorphous carbon fibers. The electrochemical test demonstrates that the irreversible capacity at first charge-discharge process is 294.9 mAh/g, which is due to the formation of solid electrolyte interface （SEI） film between the electrode and electrolyte. In addition, this composite material has very high columbic effi- ciency and excellent cycle stability, both at a low （0.1C, 0.2C and 0.5C） and high （1.0C and 2.0C） rates.