SiFe@C负极复合材料的结构及性能

《复合材料学报》优先在线发表论文。

摘  要：以SiFe合金、沥青为原料，采用机械球磨和高温热解法制备了SiFe@C负极复合材料，并对SiFe及一系列不同热解温度下制备的SiFe@C复合材料进行对比研究。利用XRD、SEM、TEM、X射线能谱仪（EDS）和恒流充放电测试仪对SiFe@C复合材料的物相、颗粒形貌及电化学性能进行表征，结果表明，在850℃热解温度下制得的SiFe@C负极复合材料首次放电比容量达到1376.25mAh/g，首次库仑效率为86.35%，经过70次循环后放电比容量为940.33mAh/g，库仑效率达到98.78%，容量保持率为76.32%，循环性能远高于SiFe和其他热解温度下的SiFe@C复合材料，而且具有良好的倍率性能。

关键词：锂离子电池；SiFe@C负极复合材料；机械球磨；热解温度；碳包覆

Abstract: SiFe@C anode materials were prepared by mechanical ball milling and high-temperature pyrolysis method with SiFe and pitch as the raw materials, and the characteristics of a series of SiFe@C composites prepared at different pyrolysis temperatures were compared with those of uncoated SiFe. The phase composition, morphology and electrochemical performance of SiFe@C anode composites were detected by XRD, SEM, TEM, energy disperse spectroscopy (EDS) and constant current charge-discharge test. The results reveal that the initial discharge specific capacity of SiFe@C composite electrode prepared at 850℃ is 1376.25mAh/g with the initial coulombic efficiency of 86.35%. After 70 cycles, the discharge specific capacity is 940.33mAh/g, the coulombic efficiency is 98.78% and the capacity retention rate is 76.32%, which indicates that its cycling stability and rate capability is much higher than the SiFe and other SiFe@C electrode composites obtained at other temperatures.

Keywords: lithium ion battery; SiFe@C anode composites; mechanical ball milling; pyrolysis temperature; carbon-coating

作者：程成等，昆明理工大学 材料科学与工程学院，云南昆明

通讯作者：肖方明，广东省稀土开发及应用重点实验室，广东广州

全文详见中国知网学术期刊优先数字出版。