Structure and property of SiFe@C anode composites
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摘要: 以SiFe合金和沥青为原料,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、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1 376.25 mAh/g,首次库仑效率为86.35%,经过70次循环后放电比容量为940.33 mAh/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。 Abstract: The 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, 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 1 376.25 mAh/g with the initial coulombic efficiency of 86.35%. After 70 cycles, the discharge specific capacity is 940.33 mAh/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.-
Key words:
- lithium ion battery /
- SiFe@C /
- anode composites /
- mechanical ball milling /
- pyrolysis temperature /
- carbon-coating
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